Magma is the
hot liquid rock under the surface of the Earth, it is known as lava after it
comes out of a volcano.
Natural gas
doesn't have an odour, strong smells are added to it by humans so it can be
detected when there are leaks.
Hawaii is moving
towards Japan at the speed of 10cm a year. This is because they are on
different tectonic plates.
The worlds
largest desert is the Sahara, it covers about one third of Africa!
Stretching
out to an impressive length of 6696 kilometres (4160 miles) long, the Nile
River is the longest river on earth.
The volcanic
rock known as pumice is the only rock that can float in water.
Mt Everest
is the highest mountain on earth, its peak reaches 8,848 metres (29028 feet)
above sea level.
On average
the Atlantic Ocean is the saltiest of Earth’s major oceans.
Earthquakes
that occur out at sea can cause huge tsunamis capable of reaching land and
endangering people.
The earth
isn't perfectly round, it is slightly fattened at the north and south poles.
Scared of
the Bermuda Triangle? Despite its reputation it is actually part of a common
sailed shipping route.
Scientists
have the dated the Earth as being between 4 and 5 billion years old!
Talc is the
softest mineral found on Earth, reaching just 1 on Mohs scale of hardness, it
is often used to make talcum powder.
Although
earthquakes can be deadly, most are very small and not even felt by humans.
Volcanoes
Volcanoes
are openings in the Earth’s surface. When they are active they can let ash, gas
and hot magma escape in sometimes violent and spectacular eruptions.
The word
volcano originally comes from the name of the Roman god of fire, Vulcan.
Volcanoes
are usually located where tectonic plates meet. This is especially true for the
Pacific Ring of Fire, an area around the Pacific Ocean where over 75% of the
volcanoes on Earth are found.
While most
volcanoes form near tectonic boundaries, they can also form in areas that
contain abnormally hot rock inside the Earth. Known as mantle plumes, these
hotspots are found at a number of locations around the globe with the most
notable being in Hawaii.
Hot liquid
rock under the Earth’s surface is known as magma, it is called lava after it
comes out of a volcano.
Some famous
volcanic eruptions of modern times include Mount Krakatoa in 1883, Novarupta in
1912, Mount St Helens in 1980 and Mt Pinatubo in 1991.
While we
certainly have some big volcanoes here on Earth, the biggest known volcano in
our solar system is actually on Mars. Its name is Olympus Mons and it measures
a whooping 600km (373 miles) wide and 21km (13 miles) high.
The object
with the most volcanic activity in our solar system is Io, one of Jupiter’s
moons. Covered in volcanoes, its surface is constantly changing to the large
amount of volcanic activity.
Most people
think of volcanoes as large cone shaped mountains but that is just one type,
others feature wide plateaus, fissure vents (cracks were lava emerges) and
bulging dome shapes.
There are
also volcanoes found on the ocean floor and even under icecaps, such as those
found in Iceland.
Volcanoes
can be active (regular activity), dormant (recent historical activity but now
quiet) or extinct (no activity in historical times and unlikely to erupt
again). While these terms are useful, scientists are more likely to describe
volcanoes by characteristics such a how they formed, how they erupt and what
their shape is.
Common
volcanic gases include water vapor, carbon dioxide, sulfur dioxide, hydrogen
chloride, hydrogen fluoride and hydrogen sulfide.
Volcanic
eruptions can send ash high into the air, over 30km (17 miles) above the
Earth’s surface.
Large
volcanic eruptions can reflect radiation from the Sun and drop average
temperatures on Earth by around half a degree. There have been several examples
of this over the last century.
Pumice is a
unique volcanic rock that can float in water. It can also be used as an
abrasive and is sometimes used in beauty salons for removing dry skin.
Gases
Like solids
and liquids, gas is a common state of matter.
Pure gases
are made up of just one atom. Neon is an example of a pure gas.
Elemental
gases are made up of two or more of the same atoms joined together. Hydrogen
gas (H2) is an example an elemental gas.
Compound
gases contain a combination of different atoms. Carbon monoxide (CO) is an
example of a compound gas.
The air we
breathe here on Earth is made up of different gases. It contains around 78%
nitrogen, 21% oxygen, 1% argon and a small amount of other gases.
Natural gas
contains mostly methane, it is used as a fuel to generate electricity and is
common in the home where it can be used for heating, cooking and other
purposes.
Gas pressure
is measured in pascals.
The helium
balloons you get at parties and carnivals float because helium is lighter than
the air surrounding it.
Noble gases
are a group of chemical elements that are very stable under normal conditions.
Naturally occurring noble gases include helium, neon, argon, krypton, xenon and
radon.
The ozone
layer that protects Earth from the Sun’s potentially damaging UV light is made
up of ozone (O3), an oxygen allotrope containing 3 oxygen atoms bound together.
Nitrous
oxide (N20) is a gas with interesting properties that allow it to be used in a
variety of different ways, these include as an anesthetic in hospitals (you may
have heard it referred to as laughing gas) and to increase the power of engines
in motor racing (often called nitrous or just NOS).
Hydrogen
The chemical
symbol of hydrogen is H. It is an element with atomic number 1, this means that
1 proton is found in the nucleus of hydrogen.
Hydrogen is
the lightest, simplest and most commonly found chemical element in the
Universe, making up around 75% of its elemental mass.
Hydrogen is
found in large amounts in giant gas planets and stars, it plays a key role in
powering stars through fusion reactions.
Hydrogen is
one of two important elements found in water (H2O). Each molecule of water is
made up of two hydrogen atoms bonded to one oxygen atom.
In 1766,
during an acid metal reaction, Henry Cavendish first formally recognized
hydrogen. In 1781 he also found that hydrogen produces water when burned. While
Cavendish is usually given credit for the discovery of hydrogen as an element,
it had been produced by earlier scientists who were unaware of hydrogen as a
unique chemical element.
It wasn’t
until a few years later (1783) that hydrogen was given its name. The word
hydrogen comes from the Greek word hydro (meaning water) and genes (meaning
creator).
Hydrogen gas
has the molecular formula H2. At room temperature and under standard pressure
conditions, hydrogen is a gas that is tasteless, odorless and colorless.
Hydrogen can
exist as a liquid under high pressure and an extremely low temperature of 20.28
kelvin (−252.87°C, −423.17 °F). Hydrogen is often stored in this way as liquid
hydrogen takes up less space than hydrogen in its normal gas form. Liquid
hydrogen is also used as a rocket fuel.
Under
extreme compression hydrogen can also make a transition to a state known as
metallic hydrogen. Laboratory research into this area is ongoing as scientists
continue efforts to produce metallic hydrogen at low temperature and static
compression.
Hydrogen is
used to power a range of new alternate fuel vehicles. The chemical energy of
hydrogen is converted by a combustion method similar to current engines or in a
fuel cell which produces water and electricity by reacting hydrogen with
oxygen.
Engineers
and car manufacturers are researching the possibility of using hydrogen gas as
an efficient and viable car fuel. One of the possibilities involves storing
hydrogen as a solid state in car fuel tanks. While there are many challenges
involved in this process it would allow for greater hydrogen storage in
vehicles, allowing them to travel for longer before refueling.
Hydrogen
peroxide is a chemical compound with the molecular formula H2O2. It is often
used as a hair bleach or cleaner. At certain concentrations it can also be used
to clean wounds.
Hydrogen was
used for air travel from 1852 when the first hydrogen lifted airship was
created by Henri Giffard. Later airships that used hydrogen were called
zeppelins and while they were reliable and safe for the majority of the time
their use was stopped soon after the Hindenburg disaster in 1937. The
Hindenburg airship was destroyed in a midair fire over New Jersey that was both
filmed and broadcast live on radio.
Hydrogen is
commonly used in the petroleum and chemical industries and is also widely used
for many physics and engineering applications such as welding or as a coolant.
Hydrogen can
be potentially dangerous to humans due to fires that can start when it is mixed
with air, our inability to breathe it in its pure oxygen free form and also in
its extremely cold liquid state.
Nitrogen is fascinating element with many unique properties
and uses related to fertilizer, dynamite, medical anesthetic and even car
racing
Nitrogen is
a chemical element with the symbol N and atomic number of 7.
Under normal
conditions nitrogen is a colorless, odorless and tasteless gas.
Nitrogen
makes up around 78% of the air you breathe.
Nitrogen is
present in all living things, including the human body and plants.
Nitrogen gas
is used in food storage to keep packaged or bulk foods fresh. It is also used
in the making of electronic parts, for industrial purposes and has many other
useful applications.
Nitrogen gas
is often used as an alternative to carbon dioxide for storing beer in
pressurized kegs. The smaller bubbles it produces is preferred for some types
of beer.
Titan, the
largest moon of Saturn, has an atmosphere nearly entirely made of nitrogen
(over 98%). It is the only moon in our solar system known to have a dense
atmosphere.
Nitrogen is
in a liquid state when at a very low temperature. Liquid nitrogen boils at 77
kelvin (−196 °C, −321 °F). It is easily transported and has many useful
applications including storing items at cold temperatures, in the field of
cryogenics (how materials behave at very low temperatures), as a computer
coolant (a fluid used to prevent overheating), removing warts and much more.
Decompression
sickness (also known as the bends) involves nitrogen bubbles forming in the
bloodstream and other important areas of the body when people depressurize too
quickly from scuba diving. Similar situations can occur for astronauts and
those working in unpressurized aircraft.
Nitrous
oxide (also known as laughing gas or by its chemical formula N2O) is used in
hospitals and dental clinics as an anesthetic (removing or reducing pain and
general awareness for various surgeries).
Nitrous
oxide is also used in motor racing to increase the power of engine and speed of
the vehicle. When used for this purpose it is often referred to as nitrous or
NOS.
Nitrous
oxide is a considerable greenhouse gas and air pollutant. By weight is has
nearly 300 times more impact than carbon dioxide.
Nitroglycerin
is a liquid used to create explosives such as dynamite. It is often used in the
demolition and construction industries as well as by the military.
Nitric acid
(HNO3) is a strong acid often used in the production of fertilizers.
Ammonia
(NH3) is another nitrogen compound commonly used in fertilizers.
Oxygen is an element with the chemical symbol O and atomic
number 8.
Oxygen is a
very reactive element that easily forms compounds such as oxides.
Under
standard temperature and pressure conditions two oxygen atoms join to form
dioxygen (O2), a colorless, tasteless and odorless gas.
Oxygen is
essential to human life, it is found in the air we breathe and the water we
drink (H20).
Oxygen makes
up around 21% of the air you breathe. It is also the most common element in the
Earth’s crust (around 47%) and the third most common element in the Universe
(but far less than hydrogen and helium, the two most common).
The large
amount of oxygen on Earth is supported by the oxygen cycle which involves the
movement of oxygen between the air, living things and the Earth’s crust.
Photosynthesis (a process that converts carbon dioxide into organic compounds
using sunlight) plays a major role in this cycle.
Ozone (O3)
is an allotrope (different form) of oxygen that combines three oxygen atoms
together. While ground level ozone is an air pollutant, the ozone layer in the
Earth’s upper atmosphere provides protection from the suns harmful rays by
filtering UV light.
The sun’s
mass is made up of around 1% oxygen.
Between 1770
and 1780, Swedish pharmacist Carl Wilhelm Scheele, British clergyman Joseph
Priestley and French chemist Antoine Laurent Lavoisier researched, documented
and helped discover oxygen. The name oxygen was first used by Lavoisier in
1777.
Oxygen
therapy is used as a common medical treatment. You may have seen patients on TV
or in real life using an oxygen mask or nasal cannula (a plastic tube that fits
behind the ears and delivers oxygen through the nostrils).
Oxygen has a
number of other practical uses such as smelting metal from ore, water
treatment, as an oxidizer for rocket fuel and a number of other industrial,
chemical and scientific applications.
Concentrated
oxygen promotes fast combustion. While a spark or heat is still needed to start
a fire, having concentrated oxygen near various fuels can be very dangerous.
Helium is a chemical element with the symbol He and atomic
number 2.
Helium is a
colorless, tasteless and odorless gas.
Helium is
the second most common element in the Universe (after hydrogen), making up
around 24% of its mass.
Helium is
part of a group of chemical elements called noble gases, the other five that
occur naturally are neon, argon, krypton, xenon and radon. Under normal
conditions they share similar properties, including being less likely to
participate in chemical reactions due to their outer shell of electrons being
full. Helium is the second least reactive element after neon.
French and English
astronomers Pierre Janssen and Norman Lockyer are jointly credited with
discovering helium after spectral analysis of sunlight following a solar
eclipse in 1868.
The word
helium comes from the Greek word meaning sun (helios). It was named by Lockyer
and English chemist Edward Frankland.
The USA is
the world’s largest supplier of helium, with many reserves found in large
natural gas fields.
The rate at
which helium is currently being used by humans is much faster than the rate at
which the reserves are being replenished. New technologies for obtaining or
recycling helium are one way for gas companies to help slow this problem.
Because
helium is lighter than air it is commonly used to fill airships, blimps and
balloons. As it doesn’t burn or react with other chemicals, helium is
relatively safe to use for this purpose.
While
hydrogen is 7% more buoyant than helium it has a much higher fire risk.
You might
notice the helium balloon you got from the amusement park slowly falling to the
ground after a few days, this happens as the helium gradually leaks from the
balloon.
Helium has a
lifting force of around one gram per liter. A balloon that holds 10 liters of
helium should therefore lift an object weighing 10 grams. Unfortunately you’ll
need around 5000 of these balloons if you weigh around 50kgs and want to get
off the ground.
The balloon
boy hoax from October 15, 2009 led people to believe that a six year old boy
had floated away in a home made helium balloon when in fact he was hiding at
his house the whole time.
Because
helium is less dense than normal air, when inhaled from a source such as a
helium balloon it briefly changes the sound of a person’s voice, making it much
sound much higher. However, breathing in too much helium can be very dangerous,
potentially choking people due to a lack of oxygen.
Helium can
be in a liquid and even solid state but they can only occur at temperatures
near absolute zero.
Liquid
helium is used to cool metals for superconductivity use. The European
Organization for Nuclear Research’s (CERN) Large Hadron Collider uses liquid
helium to maintain an extremely low temperature.
Helium is
often used in space programs, displacing fuel in storage tanks and having other
rocket fuel applications.
Carbon is a chemical element with the symbol C and atomic
number 6.
The word
carbon comes from the Latin word carbo, meaning coal.
Carbon forms
a large number of compounds, more than any other element. Because of its
willingness to bond to other nonmetallic elements it is often referred to as
the building block of life.
While carbon
forms many different compounds it is a relatively unreactive element.
There are
several allotropes (different forms) of carbon with the three most well known
being amorphous carbon (coal, soot etc), diamond and graphite.
The
properties of diamond and graphite are very different with diamond being
transparent and very hard while graphite is black and soft (soft enough to
write on paper).
Graphite is
used for its thermal insulation (lower rate of heat transfer) properties. It is
also a very good conductor or electricity.
The carbon
atoms in graphite are bonded in flat hexagonal lattices and layered in sheets.
Carbon is
the 4th most common element in the Universe (after hydrogen, helium and
oxygen). It is the 15th most common element in the Earth’s crust while it is
the second most common element in the human body (behind oxygen).
Carbon has
the highest melting point of all elements, around 3500 °C (3773 K, 6332 °F).
Hydrocarbons
are organic compounds made entirely of molecules featuring just hydrogen and
carbon. Organic chemistry involves the study of hydrocarbons.
The simplest
hydrocarbon compound is methane (CH4).
Carbon was
discovered by early human civilizations in the form charcoal and soot.
The term
carbon footprint refers to the amount of greenhouse gas emissions caused by a
country, organization or individual person.
The carbon
cycle is the process in which carbon is exchanged between all parts of Earth
and its living organisms. It is of vital importance to life on Earth, allowing
carbon to be continually reused and recycled.
Carbon is
found in the Earth’s atmosphere in the form of carbon dioxide (CO2). Although
it only makes up a small percentage of the atmosphere it plays an important
role, including being used by plants during photosynthesis.
Carbon
monoxide (CO) is very toxic to both humans and animals. It forms in conditions
when there is not enough oxygen to form carbon dioxide (CO2). In many countries
around the world, carbon monoxide poisoning is the most common kind of fatal
poisoning.
Carbon fiber
is a strong material that consists of thin fibers made up largely of carbon
atoms which are bonded together in microscopic crystals. It is very useful for
applications needing high strength and low eight.
Fossil fuels
such as methane gas and crude oil (petrol) play a large role in modern
economies.
Plastics are
made from carbon polymers. Carbon is used to form alloys with iron such as
carbon steel.
Graphite and
clay are combined to make the lead used in pencils.
Charcoal is
commonly used for grilling food on barbeques
Coal is made largely of carbon
but also features other elements such as hydrogen, oxygen, sulfur and nitrogen.
Coal starts
off as plant matter at the bottom of water. It is eventually covered and deeply
buried by sediments where over time metamorphosis (a change in form) takes
place.
Different
types of coal contain different amounts of carbon. Lignite contains only around
60 to 75%, while anthracite contains more than 92%.
Anthracite
is a hard, shiny, black coal that burns with a blue, smokeless flame. While
most forms of coal are associated with sedimentary rock, anthracite undergoes
metamorphism and is linked to metamorphic rocks.
Coal has
long been burned to create electricity and heat. The use of coal is increasing
every year, in 2006 the world consumed over 6,000,000,000,000 kilograms of
coal!
Coal is the
world’s largest source of energy for the production of electricity.
Coal is
converted to electricity by being burned in a furnace with a boiler. The boiler
water is heated until it becomes steam, with the steam then spinning turbines
and generators to create the electricity.
Nearly 70%
of China’s electricity comes from coal. In total, coal produces around 40% of
the world’s electricity.
Coal mining
and the subsequent burning of coal can have many bad effects on both humans and
the environment. Examples of this include waste products, acid rain,
contaminated water, poisonous emissions, high levels of carbon dioxide and
increased risks of lung cancer for coal plant workers.
A popular
saying among many cultures is that if you behave badly during the year, Santa
will deliver you a lump of coal for Christmas.
Diamond is an allotrope (different form) of carbon.
The word
diamond comes from the Greek word meaning unbreakable.
The carbon
atoms in diamonds are arranged in a strong, tetrahedral structure.
Diamond is
the hardest natural material known and is often used for industrial cutting and
polishing tools.
Diamond has
a hardness of 10 on Mohs scale of mineral hardness, with 1 being the softest
(talc) and 10 being the hardest.
Diamond is
the best known thermal conductor (heat transfer) among naturally occurring
substances.
Under the
normal pressures and temperatures we experience on the Earth’s surface,
diamonds are actually thermodynamically unstable, slowly transforming into
graphite. Yes, you read that correctly, diamonds are indeed turning into
graphite, but thankfully for all those diamond owners out there it’s a process
that is far too slow for humans to notice.
Most of the
Earth’s natural diamond deposits are found in Africa.
Around
26,000 kilograms (57,000 lb) of diamonds are mined around the world every year.
They are worth billions of dollars to the powerful companies that control their
production.
Diamonds
have often been a source of conflict and controversy, the term blood diamond
refers to a diamond mined in an unstable area and sold to finance war. This
issue was brought to public attention in the 2006 movie named Blood Diamond
(starring Leonardo DiCaprio and Jennifer Connelly).
Diamond is
the world’s most popular and sought after gemstone. They are frequently worn as
part of jewelry such as rings and necklaces. As well as their rarity, they are
also well suited to jewelry because they polish well and can only be scratched
by other diamonds.
Diamonds are
cut with considerable precision to optimize the luster and attention gathering
shine of each specific diamond.
Diamonds are
valued according to their cut, color, carat and clarity.
Over the years
there have been many famous (and very expensive) diamonds. The following are
four well known examples:
The
Koh-i-Noor diamond was found in India and once thought of as the largest
diamond in the world. It is now part of the British Crown Jewels in the Tower
of London.
The 45.52
carat Hope Diamond appears blue because of boron in its crystal structure and
is famous for supposedly being cursed.
Discovered
in the Kimberley Mine in South Africa, the Tiffany Yellow Diamond weighed an
amazing 287.42 carats (57.484 g) when discovered. It was later sold to a New
York jeweler named Charles Tiffany who had it cut into a cushion shape of
128.54 carats (25.708 g) with 90 facets to show off its beauty.
After being
originally found by a slave in an Indian mine, the now 140.64 carat (28.1 g)
Regent Diamond has been through an epic history including an English sea
merchant and French royalty. It is now on display at the Louvre, where it has
been on display since 1887.
Naturally
occurring diamonds are formed over billions of years under intense pressure and
heat. They are often brought to the Earth’s surface by deep volcanic eruptions.
The
technology for synthetic diamonds was researched in the 1940’s and the first
synthetically created diamond was produced in the 1950’s.
There are a
number of techniques for producing synthetic diamonds, these include
high-pressure high-temperature synthesis, chemical vapor deposition and
detonation synthesis (literally blowing up carbon with explosives to create
extremely small diamond grains).
The
synthesized material known as cubic zirconia is a crystalline form of zirconium
dioxide (ZrO2). It is at times in competition with diamond because as well as
being hard, optically flawless and colorless, it is also durable and cheap.
Water is made up of two elements, hydrogen and oxygen. Its
chemical formula is H2O.
Each
molecule of water is made up of two hydrogen atoms bonded to a single oxygen
atom.
The
existence of water is essential for life on Earth.
Water has
three different states, liquid, solid and gas.
The word
water usually refers to water in its liquid state. The solid state of water is
known as ice while the gas state of water is known as steam or water vapor.
Water covers
around 70% of the Earth’s surface.
The three
largest oceans on Earth are the Pacific Ocean (largest), the Atlantic Ocean
(second largest) and the Indian Ocean (third largest). More ocean facts.
Found in the
Pacific Ocean, the Mariana Trench is the deepest known point in the world’s
oceans.
Ocean tides
are caused by the rotation of the Earth and the gravitational pull of the Moon
and Sun acting on ocean water.
Water from a
sea or ocean is known as seawater. On average, every kilogram (2.2lb) of
seawater contains around 35 grams (1.2 oz) of dissolved salt.
The freezing
point of water lowers as the amount of salt dissolved in at increases. With
average levels of salt, seawater freezes at -2 °C (28.4 °F).
The longest
river in the world is the Nile River, it reaches 6650 kilometers in length
(4132 miles).
The second
longest river in the world is the Amazon River, it reaches 6400 kilometres
(4000 miles) in length.
The longest
river in the USA is the Mississippi River, it reaches 6275 kilometers in length
(3902 miles).
Water makes
a good solvent with many sugar, salts and acids easily dissolving in it. On the
other hand oils and fats don’t mix well with water.
The water
cycle involves water evaporating (turning into a gas), rising to the sky,
cooling and condensing into tiny drops of water or ice crystals that we see as
clouds, falling back to Earth as rain, snow or hail before evaporating again
and continuing the cycle.
Water in the
form of ice is found at the polar ice caps of the planet Mars, some scientists
have also suggested the possibility of liquid water on the red planet.
Pure water
has no smell and no taste, it also has a pH level around 7.
While most
people know that water boils at 100 °C (212 °F), this is at the normal
conditions of sea level. The boiling point of water actually changes relative
to the barometric pressure. For example, water boils at just 68 °C (154 °F) on
the top of Mount Everest while water deep in the ocean near geothermal vents
can remain in liquid form at temperatures much higher than 100 °C (212 °F).
Water
expands as it cools from 4 °C to 0 °C (above 4 °C it does the opposite). In
freezing conditions, water has been known to burst water pipes as it freezes to
ice.
Water can
move up narrow tubes against the force of gravity in what is known as capillary
action. Check out this capillary action experiment for more.
Most people
around the world have access to clean drinking water but it is a major problem
in poorer areas of the world. Water pollution and low quality water can lead to
dangerous bacteria, disease and viruses such as E coli and Cryptosporidium.
Drinking
water is needed for humans to avoid dehydration, the amount you need each day
depends on the temperature, how much activity you are involved in and other
factors.
An important
use for water is in agricultural irrigation, this is when water is artificially
added to soil in order to assist the growth of crops.
Water is
used frequently by firefighters to extinguish fires. Helicopters sometimes drop
large amount of water on wildfires and bushfires to stop fires spreading and
limit the damage they can cause.
The water
industry helps deliver water to homes in various cities and countries around
the world. This can involve services such as purification, sewage treatment,
filtering, distillation and plumbing.
Electricity
can be created from hydropower, a process that uses water to drive water
turbines connected to generators. There are many hydroelectric power stations
around the world.
Water also
plays a role in cooking. Steaming and boiling food are well known cooking
methods. You may have noticed this last time you made pasta or noodles.
Water is
also used for fun. Water sports are a very popular recreational activity and
include things like swimming, surfing and waterskiing. Ice and snow is also
used in ice skating, ice hockey, skiing and snowboarding.
Although it
is still debated, it is largely recognized that the word 'chemistry' comes from
an Egyptian word meaning 'earth'.
The use of
various forms of chemistry is believed to go back as long ago as the Ancient
Egyptians. By 1000 BC civilizations were using more complex forms of chemistry
such as using plants for medicine, extracting metal from ores, fermenting wine
and making cosmetics.
Things
invisible to the human eye can often be seen under UV light, which comes in
handy for both scientists and detectives.
Humans
breathe out carbon dioxide (CO2). Using energy from sunlight, plants convert
carbon dioxide into food during a process called photosynthesis.
Chemical
reactions occur all the time, including through everyday activities such as
cooking. Try adding an acid such as vinegar to a base such as baking soda and
see what happens!
Often formed
under intense pressure over time, a crystal is made up of molecules or atoms
that are repeated in a three dimensional repeating pattern. Quartz is a well
known example of a crystal.
Athletes at
the Olympic Games have to be careful how much coffee they drink. The caffeine
in coffee is a banned substance because it can enhance performance. One or two
cups are fine but they can go over the limit with more than five. (update - as
of 2004 caffeine has been taken back off the WADA banned list but its use will
be closely monitored to prevent future abuse by athletes.)
Nile River
The length
of the Nile River is approximately 6650 kilometres (4132 miles). It is believed
to be the longest river in the world.
Located in
Africa, the Nile River lies in the following countries: Kenya, Eritrea, Congo,
Burundi, Uganda, Tanzania, Rwanda, Egypt, Sudan and Ethiopia.
The Nile
River has huge significance in regards to Ancient Egypt. Most of Ancient
Egypt’s historical sites are located along the banks of the Nile River
including cities such as Luxor and Cairo.
In 2004, the
White Nile Expedition became the first to navigate the entire length of the
Nile River. The expedition began in Uganda and finished in Rosetta, taking four
months and two weeks to complete.
The Nile
Delta in Northern Egypt is where the Nile River drains in to the Mediterranean
Sea. It is around 160 kilometres (100 miles) in length and spreads out over 240
kilometres (149 miles) of coastline. It is rich in agriculture and has been
farmed for thousands of years.
Around 40
million people (half of Egypt’s population) live in the Nile Delta region.
In 1787, the
famous Rosetta stone was found in the Nile Delta in the city of Rosetta. This
Ancient Egyptian artifact played a key role in modern understanding of Egyptian
hieroglyphics.
The Aswan
High Dam was built in 1970 to help regulate flooding of the Nile River. Before
the Aswan Dam was built, years that featured high levels of water could wipe
out crops while years of low level water could produce famines and drought. The
dam helps control these water levels.
The Amazon River is located in
South America. It runs through Guyana, Ecuador, Venezuela, Bolivia, Brazil,
Colombia and Peru.
The length
of the Amazon River is approximately 6400 kilometres (4000 miles).
During the
wet season, the Amazon River can reach over 190 kilometres (120 miles) in
width.
There are no
bridges that cross the Amazon, mostly because there is no need, the majority of
the Amazon River runs through rainforests rather than roads or cities.
The largest
city along the Amazon River is Manaus. Located in Brazil it is home to over 1.7
million people.
There are
over 3000 known species of fish that live in the Amazon River, with more
constantly being discovered.
Anacondas
lurk in the shallow waters of the Amazon Basin, they are one of the largest
snakes in the world and occasionally attack larger animals such as goats that
get to close the water.
The Amazon
River is also home to the piranha, a meat eating type of fish! Being
carnivores, piranhas are known to attack in groups, preying on livestock that
strays into the water and possibly appearing in one or two of your own
nightmares
The length
of the Mississippi River is approximately 2,320 miles
(3,730 km), slightly shorter than the Missouri River.
The
Mississippi and Missouri Rivers combine to form the longest river system in the
USA and North America. It is also the fourth longest in the world.
At its
widest point, the Mississippi River stretches out over 7 miles (11 km) in
width.
The
Mississippi River lies in the following ten US states: Louisiana, Mississippi,
Arkansas, Tennessee, Kentucky, Missouri, Illinois, Iowa, Wisconsin and
Minnesota.
The Mississippi
River has had strong historical significance in the USA from Native American
tribes through to European explorers, the American Civil War, the Great
Mississippi Flood of 1927 and its modern commercial uses.
The first
bridge built across the Mississippi River was in 1855 with the first railroad
bridge finished a year later in 1856.
Martin
Strel, a Slovenian swimmer who is famous for swimming the length of entire
rivers conquered the Mississippi over 68 days in 2002.
Many of Mark
Twain’s famous stories are related to or take place near the Mississippi River,
this includes the well known ‘Adventures of Huckleberry Finn’.
The longest
river in the world is the Nile River, it reaches around 6650 kilometers in
length (4132 miles). The second longest river in the world is the Amazon River,
it reaches around 6400 kilometres in length (4000 miles).
The longest
river in the USA is the Missouri River, stretching around 2,340 miles (3,770
km) in length (slightly longer than the Mississippi River). The two combine to
form the longest river system in North America, reaching around 6275 kilometers
in length (3902 miles).
Small rivers
often have different names which include creek, stream and brook.
Rivers
normally contain freshwater.
The word
upriver (or upstream) refers to the direction of the river’s water source,
while downriver (or downstream) refers to the direction in which the water
flows, i.e. towards the end of the river.
Rivers have
many uses which include fishing, bathing, transport, rafting and swimming among
others.
Most of the
world’s major cities are located near the banks of rivers.
The Ganges,
Yangtze and Indus rivers are three of the most polluted on Earth.
The University
Boat Race is held every year on the Thames River in London between the Oxford
University Boat Club and the Cambridge University Boat Club. The crews feature
eight members who battle it out on the 6,779 m (4 miles and 374 yards) course.
The Colorado
River travels through the south western United States and north western Mexico,
it is home to the famous Hoover Dam.
On January
15 2009, a US Airways plane successfully made an emergency landing in the
Hudson River that runs through New York. After being hit by birds, the pilot of
flight 1549 managed to land the plane in the river with the loss of no lives.
Highest Mountains on each Continent
of the Earth
|
Mountain name
|
Metres
|
Feet
|
Country
|
Continent
|
|
Mount Everest
|
8848
|
29029
|
Nepal, China
|
Asia
|
|
Aconcagua
|
6962
|
22841
|
Argentina
|
South America
|
|
Mount McKinley
|
6194
|
20320
|
USA
|
North America
|
|
Mount Kilimanjaro
|
5892
|
19340
|
Tanzania
|
Africa
|
|
Mount Elbrus
|
5642
|
18510
|
Russia
|
Europe
|
|
Vinson Massif
|
4892
|
16050
|
NA
|
Antarctica
|
|
Mount Kosciuszko
|
2228
|
7310
|
Australia
|
Australasia
|
Highest
Mountains in the World
|
Number
|
Mountain name
|
Metres
|
Feet
|
Location
|
|
1.
|
Mount Everest
|
8848
|
29029
|
Border of Nepal and Tibet (China)
|
|
2.
|
K2
|
8611
|
28251
|
Border of Pakistan and China
|
|
3.
|
Kangchenjunga
|
8586
|
28169
|
Border of Nepal and India
|
|
4.
|
Lhotse
|
8516
|
27940
|
Border of Nepal and Tibet (China)
|
|
5.
|
Makalu
|
8485
|
27838
|
Border of Nepal and Tibet (China)
|
|
6.
|
Cho Oyu
|
8188
|
26864
|
Border of Nepal and Tibet (China)
|
|
7.
|
Dhaulagiri
|
8167
|
26795
|
Nepal
|
|
8.
|
Manaslu
|
8163
|
26781
|
Nepal
|
|
9.
|
Nanga Parbat
|
8126
|
26660
|
Pakistan
|
|
10.
|
Annapurna
|
8091
|
26545
|
Nepal
|
Ocean
Around 70% of the Earth’s surface is
covered by oceans.
The world’s oceans contain enough
water to fill a cube with edges over 1000 kilometres (621 miles) in length.
Ocean tides are caused by the Earth
rotating while the Moon and Sun’s gravitational pull acts on ocean water.
While there are hundreds of
thousands of known marine life forms, there are many that are yet to be
discovered, some scientists suggest that there could actually be millions of
marine life forms out there.
Oceans are frequently used as a
means of transport with various companies shipping their products across oceans
from one port to another.
The largest ocean on Earth is the
Pacific Ocean, it covers around 30% of the Earth’s surface.
The Pacific Ocean’s name has an
original meaning of ‘peaceful sea’.
Located to the east of the Mariana
Islands in the western Pacific Ocean, the Mariana Trench is the deepest known
area of Earth’s oceans. It has a deepest point of around 11000 metres (36000
feet).
The Pacific Ocean contains around
25000 different islands, many more than are found in Earth’s other oceans.
The Pacific Ocean is surrounded by
the Pacific Ring of Fire, a large number of active volcanoes.
The second largest ocean on Earth is
the Atlantic Ocean, it covers over 21% of the Earth’s surface.
The Atlantic Ocean’s name refers to
Atlas of Greek mythology.
The
Bermuda Triangle is located in the Atlantic Ocean,
Located in the Atlantic Ocean, the
Bermuda Triangle falls between Bermuda, Puerto Rico and Florida.
The Bermuda Triangle has long been
believed to be the site where a number of mysterious plane and boat incidents
have occurred.
While it has become part of popular
culture to link the Bermuda Triangle to paranormal activity, most
investigations indicate bad weather and human error are the more likely
culprits.
Research has suggested that many
original reports of strange incidents in the Bermuda Triangle were exaggerated
and that the actual number of incidents in the area is similar to that of other
parts of the ocean.
While its reputation may scare some
people, the Bermuda Triangle is actually part of a regularly sailed shipping
lane with cruise ships and other boats also frequently sailing through the
area.
Aircraft are also common in the
Bermuda Triangle with both private and commercial planes commonly flying
through the air space.
Stories of unexplained
disappearances in the Bermuda Triangle started to reach public awareness around
1950 and have been consistently reported since then.
Unverified supernatural explanations
for Bermuda Triangle incidents have included references to UFO’s and even the
mythical lost continent of Atlantis.
Other explanations have included
magnetic anomalies, pirates, deliberate sinkings, hurricanes, gas deposits,
rough weather, huge waves and human error.
Some famous reported incidents
involving the Bermuda Triangle include:
The USS Cyclops and its crew of 309
that went missing after leaving Barbados in 1918.
The TBM Avenger bombers that went
missing in 1945 during a training flight over the Atlantic.
A Douglas DC-3 aircraft containing
32 people that went missing in 1958, no trace of the aircraft was ever found.
A yacht was found in 1955 that had
survived three hurricanes but was missing all its crew.
Amelia Earhart became the first
female to fly solo across the Atlantic Ocean in 1932.
The third largest ocean on Earth is
the Indian Ocean, it covers around 14% of the Earth’s surface.
During winter the Arctic Ocean is
almost completely covered in sea ice.
While some disagree on whether it is
an ocean or just part of larger oceans, the Southern Ocean includes the area of
water that encircles Antarctica.
What
are fossils and what is paleontology?
Paleontology is the branch of
biology that studies the forms of life that existed in former geologic periods,
primarily by studying fossils.
The only direct way we have of
learning about dinosaurs is by studying fossils. Fossils are the remains of
ancient animals and plants, the traces or impressions of living things from
past geologic ages, or the traces of their activities. Fossils have been found
on every continent on Earth.
The word fossil comes from the Latin
word fossilis, which means, "dug up".
Most fossils are excavated from sedimentary rock layers (Sedimentary
rock is rock that has formed from sediment, like sand, mud, and small pieces of
rock).
Over long periods of time, these
small pieces of debris are compressed (squeezed) and are buried under more and
more layers of sediment that piles up on top of it. Eventually, they are
compressed into sedimentary rock.
The fossil of a bone doesn't have
any bone in it! A fossilized object has
the same shape as the original object, but is chemically more like a rock.
How are fossils formed?
Some animals were quickly buried
after their death (by sinking in mud, being buried in a sandstorm, etc). Over
time more and more sediment covered the remains. The parts of the animals that didn't rot
(usually the harder parts like bones and teeth) were encased in the newly
formed sediment. In the right
circumstances (when there is no scavengers, quick burial, not much weathering)
parts of the animal turned into fossils over time.
After a long time the chemicals in
the buried animals bodies underwent a series of changes. As the bone slowly
decayed, water infused with minerals seeped into the bone and replaced the
chemicals in the bone with rock-like minerals.
The process of fossilization involves the dissolving and replacement of
the original minerals in the object with other minerals (and or permineralization
- the filling up of spaces in fossils with minerals, and /or recrystallization
in which a mineral changes its form).
In the end we get a heavy, rock-like
copy of the original object - a fossil. The fossil has the same shape as the
original object, but is chemically more like a rock!
Other ways fossils form:
Petrification
Petrification can preserve hard and
soft parts and slowly replaces organic material with silica, calcite or pyrite,
forming a rock-like fossil. Wood is often found petrified.
Some organisms are embedded in Amber
(a hardened form of tree sap). This usually preserved insects or pieces of
plants.
Fossils of imprints may form, like
casts of dinosaur footprints. The impressions, in the right circumstances, fill
with sediments that fossilize.
Most animals did not fossilize, they
simply decayed and were lost from the fossil record. Paleontologist’s estimate that only a small
percentage of the dinosaurs that ever lived have been or will be found as
fossils.
Weather
Facts
The highest
temperature ever recorded in Antarctica is 14.6 °C (59 °F), recorded on January
5, 1974. More temperature facts.
The most
rain fall ever recorded in 24 hours is 182.5 centimetres (71.9 inches) in
Foc-Foc, La Réunion, during tropical cyclone Denise on January 8, 1966.
The most
rain fall ever recorded in one year is 25.4 meters (1000 inches) in
Cherrapunji, India.
The highest
snow fall ever recorded in a one year period was 31.1 meters (1224 inches) in
Mount Rainier, Washington State, United States, between February 19, 1971 and
February 18, 1972.
The fastest
wind speed ever recorded is 484±32 km/h (301±20 mph). This was a 3 second gust
recorded by a Doppler on Wheels (DOW) radar unit in Oklahoma City on May 3,
1999.
The heaviest
hailstone ever recorded weighed 1.0 kg (2.25 lb) and landed in Gopalganj
District, Bangladesh on April 14, 1986.
Clouds can
be categorized into a number of different types; these include cumulus,
stratus, cirrus and nimbus.
The Earth
experiences millions of lightning storms every year, they are incredible
discharges of electricity from the atmosphere that can reach temperatures close
to 54,000 °F (30,000 °C) and speeds of 60,000 m/s (130,000 mph).
The USA has
more tornadoes than any other country in the world, averaging around 1200 a
year. This is due largely to its unique geography which forms an area in
central USA called “Tornado Alley” which is frequently hit by tornadoes.
Tropical
cyclones (often referred to as hurricanes or typhoons) feature strong winds,
driving rain, rough seas and areas of low atmospheric pressure. They frequently
form in tropical areas of the globe and can do considerable damage to populated
areas. Examples of this include the 1970 Bhola cyclone, Typhoon Nina which hit
China in 1975 and more recently in 2005 when Hurricane Katrina which caused
great devastation and loss of life when it hit southern parts of the USA.
The
following are useful formulas for converting degrees Fahrenheit to Celsius
(Centigrade) and vice versa:
Temperature
in degrees Fahrenheit = (Temperature in degrees Celsius x 1.8) + 32
Temperature
in degrees Celsius = (Temperature in degrees Fahrenheit - 32) x (5 / 9)
An
interesting temperature related fact is that Fahrenheit and Celsius are equal
at -40 degrees.
Recent
increases in the Earth’s temperature have been linked to human activity such as
the burning of fossil fuels. Global warming has become an important issue for
governments around the world and a number of organizations have been created to
help deal with climate change.
The hottest
temperature ever recorded on Earth is 57.8 °C (136 °F), recorded in Al
'Aziziyah, Libya on September 13, 1922.
The coldest
temperature ever recorded on Earth is −89.2 °C (−128.6 °F), recorded at Vostok
Station, Antarctica on July 21, 1983.
The highest
temperature ever recorded in the USA is 56.7 °C (134 °F), recorded in Death
Valley, California on July 10, 1913.
The highest
temperature ever recorded in New Zealand is 42.4 °C (108.3 °F), recorded in
both Rangiora and Marlborough on February 7, 1973.
The lowest
temperature ever recorded in Africa is −24 °C (−11 °F), recorded in Ifrane,
Morocco on February 11, 1935.
light
·
In physics, light refers to electromagnetic radiation. The light
we normally talk about in everyday life refers to the visible spectrum (the
part of the electromagnetic spectrum that the human eye can see).
·
Other animals can see parts of the spectrum that humans can’t. For
example, a large number of insects can see ultraviolet (UV) light.
·
UV light can be used to show things the human eye can’t see,
coming in handy for forensic scientists.
·
The wavelength of infrared light is too long to be visible to the
human eye.
·
Scientists study the properties and behaviors of light in a branch
of physics known as optics.
·
Isaac Newton observed that a thin beam of sunlight hitting
a glass prism on an angle creates a band of visible colors that includes red,
orange, yellow, green, blue, indigo and violet (ROYGBIV). This occurred because
different colors travel through glass (and other mediums) at different speeds,
causing them to refract at different angles and separate from each other.
·
Light travels very, very fast. The speed of light in a vacuum (an
area empty of matter) is around 186,000 miles per second (300,000 kilometres
per second).
·
Light travels slower through different mediums such as glass, water and air. These mediums are given a refractive
index to describe by how much they slow the movement of light. Glass has a
refractive index of 1.5, meaning that lights travels through it at around
124,000 miles per second (200,000 kilometres per second). The refractive index
of water is 1.3 while the refractive index of air is 1.0003, meaning that air
only slightly slows down light.
·
Light takes 1.255 seconds to get from the Earth to the Moon.
·
Sunlight can reach a depth of around 80 metres (262 feet) in the
ocean.
·
One of the many things Italian scientist Galileo Galilei worked on was telescopes, producing
telescopes with around 30x magnification in some of his later work. These
telescopes helped him discover the four largest moons orbiting Jupiter (later named the Galilean satellites).
·
Photosynthesis is a process that involves plants using energy from sunlight to convert carbon dioxide into food.
·
The word energy comes
from the Greek word energeia.
·
Most types of energy are either a form of kinetic energy or
potential energy.
·
Common examples include heat energy, elastic potential energy,
chemical energy, sound energy, nuclear energy, geothermal energy and
gravitational potential energy.
·
Kinetic energy refers to the energy an object has because of its
movement. A car in motion has kinetic energy, as does a basketball when you
pass or shoot it.
·
Energy can be transformed from one form to another. In lightning,
electric potential energy transforms into light, heat
and sound energy.
·
The law of conservation of energy states that energy can only be
transformed, it can’t be created or destroyed.
·
You might have heard of Albert Einstein’s famous
formula E = mc² (energy equals mass multiplied by the speed of light squared).
·
Food contains chemical energy which is used by
living organisms such as animals to grow and reproduce. Food energy is usually
measured in calories or joules.
·
Wind farms contain large numbers of wind turbines which are used
to transform wind energy into a useful energy such as electricity. The use
of wind power to generate electricity doubled between the years 2005 and 2008.
·
A person standing on a diving board above a swimming pool has
gravitational potential energy.
·
During chemical reactions, chemical energy is often transformed
into light or heat.
·
Stretched rubber bands and compressed springs are examples of
elastic potential energy.
- Metals are usually solid, good conductors of electricity and
heat, shiny when clean, strong and malleable (meaning they can be bent and
shaped).
- Gold is shiny and doesn’t corrode, this means it is a
great metal for making jewelry. More gold facts.
- The chemical symbol used for silver is Ag, this comes
from the Latin word for silver, argentum. More silver facts.
- While aluminum is the most common metal found in the
Earth's crust, the most common metal found on Earth is iron, mostly
because it makes up such a large part of the Earth's core. More iron facts.
- Copper is a good conductor of electricity and is often
used for making wires.
- At room temperature, mercury is the only metal that is
in liquid form.
- Aluminum is a good conductor of heat and is often used
to make cooking pots.
- Alkali metals such as sodium, potassium, rubidium,
caesium and francium are extremely reactive elements, just putting them in
water can result in an explosion! They are carefully stored in oil to
prevent this happening. More alkali metals facts & properties.
- Tungsten has a very high melting point, after carbon it
has the second highest melting point of all elements.
- Metals are strong and are useful for making tools,
buildings, bridges and other structures where strength is important.
- Steel is an important alloy (combination of metals)
that is created from a mixture of metals, mostly iron. There are many
different types of steel including stainless steel, galvanized steel and carbon
steel. Steel is commonly used to make a number of products including
knives, machines, train rails, cars, motors and wires.
- Bronze is a metal alloy made from copper and tin.
Copper makes up the larger amount, usually between 80 to 95%.
|
·
Silver is a
chemical element. Its chemical symbol is Ag and atomic number is 47.
·
Silver is a soft, shiny metal that is a good conductor of
electricity.
·
Silver is precious metal that has been used for many years to make
fine pieces of jewelry, coins, utensils and various pieces of art.
·
In modern times silver is also used in dentistry, electronics,
photography, mirrors and in a number of industrial applications that make use
of its unique properties.
·
You may have heard of the term sterling sliver, this is the name
given to an alloy (combination of metals) that is at least 92.5% silver by
weight. The other 7.5% is made up of other metals, usually copper.
·
Silver is found naturally by itself, as an alloy with gold or in
an ore (a rock containing various metals and elements). Silver is often found
in copper and lead ores.
·
The price of silver has fluctuated dramatically over the last
century, climbing as demand increases but dropping when large silver deposits
are found.
·
As of November 2009, gold was valued at around 65 times the value
of silver by mass.
·
The word silver is one of the few words in the English language
that is nearly impossible to rhyme. Words such as orange, purple, breadth,
wolf, depth, angst, gulf, ninth and twelfth are also difficult or impossible to
rhyme. While there are some words that do actually rhyme with these examples
they are usually very rare or hardly used in the modern English language.
- Iron is a chemical element and metal. Its chemical symbol
is Fe and its atomic number is 26.
- When iron and oxygen react in the presence of water or
moisture, rust (iron oxide) is formed. You might have noticed your bike
chain (or other parts) rusting from time to time (especially if you
haven’t been taking care of it). Another word for rusting is corrosion,
which describes the disintegration of materials such as iron and steel.
- Because iron oxidizes so easily, it is rarely found in
a pure metal form on the Earth’s surface. It is instead removed from ores
(rocks containing important minerals and elements).
- Iron is the 4th most common element in the Earth’s
crust, making up around 5% of the total (usually found as iron oxide in
minerals like hematite).
- The Earth’s core is thought to be made up of an iron
and nickel alloy.
- Gas giant plants such as Saturn and Jupiter have cores
that are rich in iron.
- Iron is the 6th most common element found in the
Universe.
- Steel is a well known and commonly used alloy made from
iron and a small amount of carbon (or sometimes other elements). The
amount of carbon is small (usually between 0.2% and 2.0%) but it makes a
huge difference to the strength.
- Steel can be around 1000 times stronger than iron in
its pure form.
- The Eiffel Tower in Paris, France is made from puddle
iron. Puddle iron is a form of wrought iron, an iron alloy with a very low
level of carbon content. Wrought iron was used commonly throughout western
history but is no longer produced in large amounts due to the availability
of steel.
- The early wrought iron used in human history actually
came from meteors!
- Cast iron is a type of iron that contains carbon,
silicon and small amount of manganese. It was used in earlier times to
build structures like cast iron bridges. Like wrought iron however, most
of its uses have been replaced by steel.
- The Iron Age was a prehistoric time when useful tools
and weapons were first made from iron and steel. The dates this occurred
in various parts of the world varies, with historians suggesting around
12th century BC in ancient Greece and 6th century BC in Northern Europe.
- In 2006, China was the world’s largest producer of
iron, making up around 33% of the world’s total production.
- Iron is relatively cheap to produce and has a large
number of different uses.
- Machines, vehicles and building structures are commonly
built from iron (usually in the form of steel).
- To prevent iron and steel suffering from rust damage,
they can be painted, coated with plastic, galvanized (coated with zinc) or
by other methods that keep out water and oxygen.
- Iron in the human body has a number of important
functions including carrying oxygen to the body in the form of hemoglobin.
Iron deficiency can be quite common (especially among women), with a
number of possible symptoms including fatigue and weakness.
- Iron rich foods include red meat, fish, tofu, beans and
chickpeas.
|
·
Lithium (Li)
|
Atomic number 3
|
Under normal conditions lithium is
the lightest of all metals. Lithium only appears naturally as part of a
compound.
|
 |
|
Sodium (Na)
|
Atomic number 11
|
Sodium is a silvery white metal
that is soft enough to be cut with a knife at room temperature.
|
 |
|
Potassium (K)
|
Atomic number 19
|
Potassium only occurs in nature as
ionic salt. It is found as part of minerals and dissolved in sea water.
|
 |
|
Rubidium (Rb)
|
Atomic number 37
|
Rubidium was discovered in 1861.
It gives a reddish violet color when burned in a a flame.
|
 |
|
Caesium (Cs)
|
Atomic number 55
|
Caesium has a melting point of
28 °C (83 °F), is one of only five metals that are liquid at or
near room temperature (the others being mercury, francium, gallium and
rubidium).
|
 |
|
Francium (Fr)
|
Atomic number 87
|
Francium was the last element
discovered in nature and it is extremely rare, scientists predict that only
20 to 30 grams of it exists on Earth.
|
 |
Sports Science Facts
·
Olympic gold medals are actually made mostly of silver.
·
Dimples on a golf ball help reduce drag, allowing the ball to fly
further than a ball without dimples.
·
Anaerobic exercise refers to high intensity activities over a
short duration (e.g. sprinting) while aerobic exercise refers to physical
activity performed at a moderate level over longer periods of time (e.g.
jogging).
·
Regular exercise helps boost the immune system.
·
The string tension of most tennis racquets is around 50 to 70
pounds (220 to 310 newtons). With lower tension a tennis racquet produces less
control and more power while higher tension produces more control and less
power.
·
The official distance of a marathon is 42.195 kilometres (26.219
miles).
·
The tallest basketball players to ever play in the NBA were Manute
Bol (from Sudan) and Gheorghe Muresan (from Romania). They were both 7 ft 7 in
tall (231 cm).
·
Common sports injuries include muscle cramps, muscle pulls, back
strains, shin splints, tennis elbow (tendonitis), sprained ankles and plantar
fasciitis (foot pain).
·
The fastest recorded tennis serve was 155 mph (249 kph),
by Andy Roddick in 2004.
·
Regulation Major League baseballs feature exactly 108 stitches.
·
Snowboarders and ice skaters glide on a thin layer of water as
their skates and boards heat the snow beneath them.
·
Modern swimwear has developed to the point where the fabric and
designs are actually faster through the water than human skin. Controversial
neck to ankle suits have been one of the reasons behind the consistent breaking
of world record times since they were introduced around the year 2000.
·
Curling stones used in the Olympic sport of curling are made from
granite.
·
Astronaut Alan Shepard played golf on the Moon after he smuggled a
golf ball and club on to the NASA Apollo 14 mission to the Moon in 1971.
·
The diameter of a full sized basketball is half the diameter of a
basketball hoop.