Laboratory Apparatus And Their Uses

Lab apparatus is an important part of chemistry and science in general. In this page you will learn about lab equipment and its uses.

Name	Description	Picture
Beaker	Used to hold and heat liquids. Multipurpose and essential in the lab.
Bottle	Bottles can be ued for storage, for mixing and for displaying.
Bunsen Burner	Bunsen burners are used for heating and exposing items to flame. They have many more uses than a hot plate, but do not replace a hot plate.
Buret	The buret is used in titrations to measure precisely how much liquid is used.
Crucible	Crucibles are used to heat small quantities to very high temperatures.
Erlenmeyer Flask	The Erlenmeyer Flask is used to heat and store liquids. The advantage to the Erlenmeyer Flask is that the bottom is wider than the top so it will heat quicker because of the greater surface area exposed to the heat.
Evaporating Dish	The Evaporating Dish is used to heat and evaporate liquids.
Florence Flask	The Florence Flask is used for heating subtances that need to be heated evenly. The bulbed bottom allows the heat to distribute through the liquid more evenly. The Florence Flask is mostly used in distillation experiments.
Food Coloring	Food Coloring is used in many experiments to show color change and to make the experiment more exciting.
Funnel	The Funnel is a piece of eqipment that is used in the lab but is not confined to the lab. The funnel can be used to target liguids into any container so they will not be lost or spilled.
Microspatula	The Microspatula, commonly called a spatula, is used for moving small amounts of solid from place to place.
Mortar and Pestle	The Mortar and Pestle are used to crush solids into powders for experiments, usually to better dissolve the solids.
Paper Towels	Paper Towels are essential to the lab environment. They will be used in almost every lab.
Pipet	The pipet is used for moving small amounts of liquid from place to place. They are usually made of plastic and are disposable
Ring Stand	Ring stands are used to hold items being heated. Clamps or rings can be used so that items may be placed above the lab table for heating by bunsen burners or other items.
Stir Rod	The stir rods are used to stir things. They are usually made of glass. Stir Rods are very useful in the lab setting.
Stopper	Stoppers come in many different sizes. The sizes are from 0 to 8. Stoppers can have holes for thermometers and for other probes that may be used.
Test tube Brush	The test tube brush is used to easily clean the inside of a test tube.
Test tube Holder	The holder is used to hold test tubes when they are hot and untouchable.
Test tube Rack	The testtube rack is used to hold testtubes while reactions happen in them or while they are not needed.
Thermometer	The thermometer is used to take temperature of solids, liquids, and gases. They are usually in oC, but can also be in oF
Tongs	Tongs are used to hold many different things such as flasks, crucibles, and evaporating dishes when they are hot.
Triangle	The triangle is used to hold crucibles when they are being heated. They usually sit on a ring stand
Volumetric Flask	The Volumetric flask is used to measure one specific volume. They are mostly used in mixing solutions where a one liter or one half a liter is needed.
Watch Glass	The watch glass is used to hold solids when being weighed or transported. They should never be heated.

COMPOUND MICROSCOPE PARTS

A high power or compound microscope achieves higher levels of magnification than a stereo or low power microscope. It is used to view smaller specimens such as cell structures which cannot be seen at lower levels of magnification.

Essentially, a compound microscope consists of structural and optical components. However, within these two basic systems, there are some essential components that every microscopist should know and understand.

These key microscope parts are illustrated and explained below.

STRUCTURAL COMPONENTS

The three basic structural components of a compound microscope are the head, base and arm.

• Head/Body houses the optical parts in the upper part of the microscope
• Base of the microscope supports the microscope and houses the illuminator
• Arm connects to the base and supports the microscope head. It is also used to carry the microscope.

When carrying a compound microscope always take care to lift it by both the arm and base, simultaneously.

OPTICAL COMPONENTS

There are two optical systems in a compound microscope: Eyepiece Lenses and Objective Lenses:

Eyepiece or Ocular is what you look through at the top of the microscope. Typically, standard eyepieces have a magnifying power of 10x. Optional eyepieces of varying powers are available, typically from 5x-30x.

Eyepiece tube holds the eyepieces in place above the objective lens. Binocular microscope heads typically incorporate a diopter adjustment ring that allows for the possible inconsistencies of our eyesight in one or both eyes. The monocular (single eye usage) microscope does not need a diopter. Binocular microscopes also swivel (Interpupillary Adjustment) to allow for different distances between the eyes of different individuals.

Objective Lenses are the primary optical lenses on a microscope. They range from 4x-100x and typically, include, three, four or five on lens on most microscopes. Objectives can be forward or rear-facing.

Nosepiece houses the objectives. The objectives are exposed and are mounted on a rotating turret so that different objectives can be conveniently selected. Standard objectives include 4x, 10x, 40x and 100x although different power objectives are available.

Coarse and Fine Focus knobs are used to focus the microscope. Increasingly, they are coaxial knobs - that is to say they are built on the same axis with the fine focus knob on the outside. Coaxial focus knobs are more convenient since the viewer does not have to grope for a different knob.

Stage is where the specimen to be viewed is placed. A mechanical stage is used when working at higher magnifications where delicate movements of the specimen slide are required.

Stage Clips are used when there is no mechanical stage. The viewer is required to move the slide manually to view different sections of the specimen.

Aperture is the hole in the stage through which the base (transmitted) light reaches the stage.

Illuminator is the light source for a microscope, typically located in the base of the microscope. Most light microscopes use low voltage, halogen bulbs with continuous variable lighting control located within the base.

Condenser is used to collect and focus the light from the illuminator on to the specimen. It is located under the stage often in conjunction with an iris diaphragm.

Iris Diaphragm controls the amount of light reaching the specimen. It is located above the condenser and below the stage. Most high quality microscopes include an Abbe condenser with an iris diaphragm. Combined, they control both the focus and quantity of light applied to the specimen.

Condenser Focus Knob moves the condenser up or down to control the lighting focus on the specimen.

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CONSTELLATION

Andromeda, the Chained Princess	Lepus, the Hare
Aquarius, the Water Bearer	Libra, the Scales
Aquila, the Eagle	Lyra, the Lyre
Ara, the Altar	Boötes, the Bear Driver
Aries, the Ram	Microscopium, the Microscope
Auriga, the Charioteer	Monoceros, the Unicorn
Camelopardalis, the Giraffe	Orion, the Hunter
Canes Venatici, the Hunting Dogs	Pegasus, the Winged Horse
Canis Major, the Great Dog	Perseus, the Hero
Carina, The Keel	Pisces, the Fishes
Cancer, the Crab	Canis Minor, the Lesser Dog
Caelum, the Sculptor’s Cheasel	Pisces, the Fish
Capricornus, the Sea Goat	Piscis Austrinus, the Southern Fish
Cassiopeia, the Queen	Puppis, the Stern
Cepheus, the King	Pyxis, the Compass
Cetus, the Whale or Sea Monster	Sagitta, the Arrow
Columba, the Dove	Sagittarius, the Archer
Corona Borealis, the Crown	Scorpius, the Scorpion
Cygnus, the Swan	Sculptor, the Sculptor
Delphinus, the Dolphin	Scutum, the Shield
Draco, the Dragon	Serpens Caput, the Serpent's Head
Equuleus, the Little Horse	Taurus, the Bull
Gemini, the Twins	Triangulum, the Triangle
Hercules	Ursa Major, the Great Bear
Lacerta, the Lizard	Ursa Minor, the Little Bear
Leo Minor, the Little Lion	Vulpecula, the Fox

Black Holes

JUPITER'S MOON EUROPA HELPS SOLVE STRIPEY MYSTERY

Last year, something strange happened to Jupiter.

Not only was the gas giant recovering from an asteroid smash, it also underwent a... change. Jupiter lost one of its trademark stripes -- a.k.a. the South Equatorial Belt (SEB) -- for no apparent reason.

Although astronomers at the time theorized that there were perhaps some high-altitude clouds blocking our view of the SEB, it wasn't until the keen infrared eyes of Keck Observatory on Mauna Kea, Hawaii, zoomed in on the planet that the SEB came into focus again.

What's more, Jupiter's moon Europa helped astronomers unravel the mystery as to where the belt has been hiding.

Using the Keck II telescope’s Adaptive Optics system, astronomers would normally point a powerful laser above the observatory to create a "guide star." This artificial point of light can then be used to detect turbulence in the Earth's atmosphere; the shimmering laser signal feeds back into the adaptive optics, allowing the telescope to slightly deform its mirror (in real-time) to compensate for the distortion.

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The result is a sharper image of an astronomical target, as atmospheric distortions can be removed from observations. It's these same distortions that can cause stars to "twinkle" at night.

So, with a little help from a little moon, an amazing infrared picture of Jupiter's inner turmoil came into focus.But there was a problem when observing Jupiter. As the planet is so bright, the laser guide star was overwhelmed and couldn't be used for Jovian observations. But all was not lost, Europa was there to lend a hand and on Nov. 30, 2010, it was very bright, right next to Jupiter in the sky. Europa became the "guide star" for the adaptive optics to sense atmospheric distortions.

Thermal infrared radiation (with a wavelength of 5 microns) was detected by Keck leaking from Jupiter's interior. When combining the thermal radiation data with near-infrared solar radiation being reflected by the upper clouds in the Jovian atmosphere, the churning detail in the cloaked SEB was revealed (pictured top).

As the SEB slowly begins to reveal itself once more, icy clouds in the upper atmosphere gradually dissipating, only the Keck infrared telescope could cut through the Jovian atmosphere to reveal the hidden trademark stripe we've been missing out on for these last few months.

About Stars: Wolf-Rayet Stars

Spectral class: WN, WC

These are very hot and blue stars with surface temperatures of 25 000 - 50 000 kelvin and a mass in the beginning of 25 times solar. Only a few hundred are known in our galaxy. WR stars cast away quickly large parts of their hull into space. Therefore in very big telecsopes they look similar to planetary nebulae.
Before the Wolf-Rayet phase they have been red supergiants or LBV which now expose their core. Supposably every star with enough mass goes through the Wolf-Rayet stadium. These stars are short before an explosion as supernova (astronomically that is. Those stars can as well still live for another several thousand years).

The very strong stellar wind is caused by a heightened accumulation of heavy elements on the surface. These block the light on its way out and therefore heat up the star, which powers the wind. The stellar wind can blow away up to one solar mass every 10 000 years.

Example: WR 124

Red Supergiant Stars

They are the largest stars in the universe in terms of volume, although they are not the most massive. 


Red supergiants (RSGs) are supergiant stars (luminosity class I) of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive. Betelgeuse and Antares are the best known examples of a red supergiant.

Stars with more than about 10 solar masses after burning their hydrogen become red supergiants during their helium-burning phase. These stars have very cool surface temperatures (3500–4500 K), and enormous radii. The five largest known red supergiants in the Galaxy are VY Canis Majoris, Mu Cephei, KW Sagitarii, V354 Cephei, and KY Cygni, which all have radii about 1500 times that of the sun (about 7 astronomical units, or 7 times as far as the Earth is from the sun). The radius of most red giants is between 200 and 800 times that of the sun, which is still enough to reach from the sun to Earth and beyond.

These massively large stars are little more than "hot vacuums", having no distinct photosphere and simply "tailing off" into interstellar space. They have a slow, dense, stellar wind and if their core's nuclear reactions slow for any reason (such as transitioning between shell fuels) they may shrink into a blue supergiant. A blue supergiant has a fast but sparse stellar wind and causes the material already expelled from the red supergiant phase to compress into an expanding shell.

The mass of many red supergiants allow them to eventually fuse elements up to iron. Near the end of their lifetimes, they will develop layers of heavier and heavier elements with the heaviest at the core.

The red supergiant phase is relatively short, lasting only a few hundred thousand to a million or so years. The most massive of the red supergiants are thought to evolve to Wolf-Rayet stars, while lower mass red supergiants will likely end their lives as a type II supernova.

The red sun around which the fictitious planet Krypton orbits in both Superman and Superman Returns is also a red supergiant (as opposed to that of a red dwarf star in the comics) that undergoes a supernova explosion, causing Krypton's destruction by means of the shockwaves emitted by the dying star (in the comic series, Krypton was destroyed by the planet's unstable cores).

About Stars: Red Supergiants

A red supergiant is the bigger version of a red giant - so far no surprise. But with these stars with more than 8 to 10 solar masses (the exact value is still uncertain) the production of energy doesn't stop at helium or carbon.
A red supergiant is made of several layers. The outer hull of red glowing hydrogen and helium is inactive. Below this is a layer in which hydrogen is fusioned to helium. In the next layer helium is fusioned to carbon. So it goes on until in the core iron is made. The supergiant shines extremely bright, but only for a short time (still several hundred thousand to million years). In the end the phase in which the star fusions sulfur and silicon to iron only lasts a few days to weeks.
From iron no more energy can be made. The core cools down and implodes. The following supernova (of type II) disrupts the star and leaves a tiny neutron star or a black hole behind.

Red supergiants are frequently very unstable, pulsate and often have a strong stellar wind which blows away their hull.

Example: Betelgeuse

Life Cycle of Stars

The Birth of a Star

In space, there exists huge clouds of gas and dust. These clouds consist of hydrogen and helium, and are the birthplaces of new stars. Gravity causes these clouds to shrink and become warmer. The body starts to collapse under its own gravity, and the temperature inside rises. After the temperature reaches several thousand degrees, the hydrogen molecules are ionized (electrons are stripped from them), and they become single protons. The contraction of the gas and the rise in temperature continue until the temperature of the star reaches about 10,000,000 degrees Celsius (18,000,000 degrees Fahrenheit). At this point, nuclear fusion occurs in a process called proton-proton reaction. Briefly, proton-proton reaction is when four protons join together and two are converted into neutrons; an 4He nucleus is formed. During this process, some matter is lost and converted to energy as dictated by Einstein's equation. At this point, the star stops collapsing because the outward force of heat balances the gravity.

The Hydrogen Burning Stage

The proton-proton reaction occurs during a period called the hydrogen-burning state, and its length depends on the star's weight. In heavy stars, the great amount of weight puts a large amount of pressure on the core, raising the temperature and speeding up the fusion process. These heavy stars are very bright, but only live for a short amount of time. After the energy from this deuteron-hydrogen fusion process ends, the star begins to contract again, and the temperature and pressure subsequently increase. Nuclear fusion occurs between the hydrogen and lithium & other light metals in the star, but this process soon ends. Contraction starts again, and the extreme high temperature and pressure cause the hydrogen to transform into helium through the carbon-nitrogen-oxygen cycle. When all the hydrogen has been used up, the star is at its largest size, and it is called a red giant. Different things can happen to the star now.

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Scenario 1:

Planetary Nebulas One scenario is that the star will continue to make energy by using hydrogen and helium outside of the core; its surface will rise and fall and the star will become a variable star. After it gets out of control, the layers of gas will pull away, forming a shell of gas known as a planetary nebula.

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Scenario 2:

White dwarf The other scenario is that the star will continue to shine through the fusion of helium nuclei, in thetriple alpha process. The star is now a white dwarf, and further contraction is prevented by the repulsion of electrons in the core.

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Supernova Very heavy stars will continue to fuse heavy elements in order to produce more energy. However, once iron is formed, it cannot be fused to make more energy since it has such a high binding energyand is therefore very stable. The core will collapse under gravity and huge amounts of gas on the surface of the star will explode out. This star is now called a supernova.

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Neutron Star After a supernova explosion, the iron core of the star may be extremely heavy, and the force of gravity may be extremely large. It then becomes a neutron star, where the repulsion between neutrons stops the contraction caused by gravity. Neutron stars consist of matter that is 100 million times denser than white dwarf matter.

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Pulsars

A neutron star may spin rapidly after a supernova explosion, and it may emit two beams of radio waves, light, and X-rays. These beams radiate in a circle because the star is spinning, and it appears that the star is pulsing on and off. Thus, it is given the name Pulsar.

Black Holes

Neutron-neutron repulsion can only counteract the force of gravity if the core of the dead star weighs less than three times the weight of the sun. In an extremely heavy core, no force can stop the matter from being squeezed into a smaller and smaller space. Nothing can escape these black holes; not even light.

The Nebula Theory

In the Beginning

The whole Solar System developed from a cloud of dust and gas called a nebula. Scientists believe that  all the stars in the Universe formed from a nebula that collects together through the force of gravity.

Astronomers believe that at the beginning of the Universe most of the matter that existed was in the form of hydrogen.

 

The hydrogen atom is the simplest atom that exists: it has one proton and one electron .

Element Factory

If most of the matter that existed was once hydrogen how did oxygen, nitrogen, iron, calcium and the rest of the elements develop? Good question!

Astronomers believe stars are the factories that made all of the other elements and that they use hydrogen as the fuel and the raw material to make them.

Stars may not be alive in the same way that we are, but they do have a beginning, a middle and an end to their existence. It just happens that a star’s lifetime is measured in many millions or billions of years. Since we tend to hang out around in life for less than a century, stars seem unchanging to us.

The Power of Attraction

In the beginning, the universe was a bunch of gas and dust spreading out in space. Over a very long time, this gas and dust started gathering together into clumps, or clouds through the force of gravity. In everything that exists, every atom has a gravitational pull that wants to attract something to it. As matter collects together, its gravitational pull gets stronger and it can reach out farther to grab more matter. That increases its gravitational pull even more.  This process continues until there is nothing more to grab.

A Star is Born

This image from the Hubble Telescope is of the Eagle Nebula. The large pillars are called "elephant trunks." They are light-years in length and are so dense that the gas in them contracts gravitationally and forms stars!  (Click on the image for a closer look.) Image Credit: J. Hester, P. Scowen (ASU), HST, NASA

Supernova 1987a

In February 1987, light reached Earth from a star more than 170 thousand  light yearsfrom Earth. The light was from a star that exploded in the nearby Large Magellanic Cloud galaxy. Named Supernova 1987a, it is the closest supernova since the invention of the telescope. The exlposion of the star shot huge amouts of gas, light, and neutrinos out into space. (Click on the image for a closer look.) Image Credit: C. S. J. Pun (GSFC) & R. Kirshner (CfA), WFPC2,HST, NASA

Let's Get Together

If the blob of stuff gets big enough, it forms a sphere or ball. The center of gravity of the sphere is in the middle. Everything is being pulled towards the very center of the sphere. If enough material is pulled toward the center, the weight of the outer parts crush the inner parts and cause the atoms to fuse, or join together to become newer, more complex atoms. This process is called fusion.

What About the Leftovers?

Whatever parts are not used to make the new atom are released as heat and light energy. Whenever atoms are fused or split, they release a lot of energy. That is how atom bombs work. That is also how stars works. Stars are not on fire in space, they are constantly having nuclear explosions. This is what makes them shine.

Here Comes the Sun

When our Sun formed from a nebula in this region of space, it gobbled up nearly all of the material for itself. The key word here is “nearly”, which means that some material was left over after the Sun was created. However, if the mass of the solar system was converted into one dollar, the Sun would be worth more than 99 cents, and all the planets, moons, asteroids and comets put together would total less than one penny!

Solar Winds

As the Sun shines, it generates what is called a solar wind. It is not wind as we know it where air moves around – because there is no air in space. It is a flow of energy outward from the Sun that acts like a wind and pushs things outward.

When the Sun grew large enough and started shining through nuclear fusion, the solar wind it created blew the remaining nebular material outward. The planets, moons asteroids and comets condensed from this leftover material in much the same way that the Sun formed – from gravitational attraction pulling nearby available material together. Heavier elements remained closer to the Sun and lighter elements were blown further out.

Density of the Planets

This explains why the inner planets of Mercury, Venus, Earth and Mars are dense, rocky planets and the outer planets of Jupiter, Saturn, Uranus (which, by the way, is properly pronounced ’YUR-uh-nis’) and Neptune are gas giants. Pluto, while still called a planet, resembles more closely the body of objects being classified as Kuiper Belt Objects. These distant objects are more like giant comets and are apparently made of materials light enough to be blown out past Neptune’s orbit.

Pluto and Beyond

This image shows the newly discovered planet-like object, "Sedna," in relation to other bodies in the solar system, including Earth and its Moon; Pluto; and Quaoar, a planetoid beyond Pluto that was until now the largest known object beyond Pluto. Sedna is bigger than an asteriod, but smaller than a planet. It is three times farther away from Earth than Pluto and is the reddest object in the Solar System, after Mars.       Not in this picture is the more recently discovered "tenth planet", 2003ub313, that is estimated to be larger than Pluto, perhaps around the size of the Moon.  See the "Big Bang Theory" page for more about this discovery. (Click on the image for a closer look.) Image Credit: NASA/JPL-Caltech

Formation of the Earth

Seeing that New Hampshire is located on Earth, let’s concentrate now on our planet’s development. Earth is one of the inner planets and is made up of the denser (heavier) elements that were left over after the Sun was formed. The current accepted theory for planet development is known as theAccretion Theory. To accrete is to gather together or add on to. Sometimes it is easier for some people to think of the Accretion Theory as the ‘Snowball Theory’. Smaller lumps of planet building material were gravitationally attracted to larger chunks of planet building material and they collided; much like gathering a bunch of smaller snowballs together to make a larger snowball.

Collision Course

Very early on in our Solar System’s history, there were many more planets than there are today, though they were all smaller than today’s planets. The nine planets (and their moons) are the bodies that ‘won’ the collision contest. The collisions haven’t stopped, they have just slowed down and most of the larger planet-sized chunks have been swallowed up (thank goodness, as you will see).

Meteors

Approximately ten tons of new material enter the Earth's atmosphere every day. Most of this debris is the size of a grain of sand or a small pebble and burns up harmlessly in the atmosphere. At night the debris is often visible as shooting stars. Scientists call these pieces of planet building material that burn up in our atmosphere, meteors. After they burn up on entry into the earth’s atmosphere, their dust settles on the surface of the Earth.

Leonid Meteor Showers

The Leonid Meteor Showers happen when the Earth passes through the tail of Comet Temple-Tuttle. When the Earth passes through the comet's tail, all the dust and debris of the comet burns up in our atmosphere and is visible as meteor showers in the night sky. The Comet Tempel-Tuttle has an eliptical orbit around the sun. Most of its orbit is in the outer solar system. It enters the inner solar system and passes by Earth every 33 years. The next pass-by of the comet will occur in 2033. (Click on the image for a closer look.) Picture Credit: NASA, Hubble Space Telescope

Meteorites

Sometimes larger chunks survive the burning trip through the atmosphere and hit the surface of the Earth. These are called meteorites. Fortunately, most of our planet’s surface is ocean, so meteorites tend to land harmlessly out at sea. On rare occasions, city sized chunks of rock and/or ice slam into Earth and cause massive destruction. Scientists believe a large meteorite that hit the Yucatan Peninsula in the Gulf of Mexico 65 million years ago at the end of the Cretaceous period led to the extinction of the dinosaurs. They think that when the meteorite hit the Earth, it sent huge quantities of dust, smoke and debris into the atmosphere all over the world. The dust, smoke and debris blocked the Sun for many weeks or months.  This caused temperatures to drop all over the planet, causing winter like conditions everywhere. Plants and animals that couldn't adapt to the sudden changes in light and temperature died, and animals that depended on these organisms for food, like the dinosaurs, eventually died as well.

Friction

The friction of huge impacts creates heat. The relentless pounding the early Earth took generated so much heat that it melted the entire planet into liquid rock.  Yup, the Earth was a floating ball of lava in space!

Feel the Heat

Try the simple experiment of rubbing your hands together briskly for ten to twenty seconds and feel the heat generated from this relatively miniscule amount of friction.

Forming Layers

While the Earth was molten, it separated into layers, like oil and vinegar salad dressing does when it is undisturbed. The heavier elements settled towards the center of the planet, the lighter materials floated on top         (Click on the image for a closer look.)
and those           Image Courtesy of Windows to the Universe, at:
materials whose        http://www.windows.ucar.edu/
densities lay
between these two extremes were settled between the heaviest and lightest two layers.

The core separated into a solid inner core consisting mainly of iron and nickel. The inner core is surrounded by a liquid metal outer core that generates an electrical current as the Earth rotates. This spinning electrical current is responsible for the magnetic field that surrounds our planet. This magnetic field protects us from some of the more deadly forms of solar radiation by deflecting those harmful rays towards the North and South Magnetic Poles and in doing so, create the Northern and Southern Lights.

As the bombardment of larger chunks slowed down, the exterior of the earth had a chance to cool and harden into a crust as it was exposed to the coldness of outer space (there was no atmosphere in the early part of the Earth formation).

The mantle stayed molten because the crust served as insulation retained the heat generated from radioactive materials in the Earth’s interior.

The mantle doesn’t just sit there, it is in constant roiling motion due to convection of the liquid rock. The term ‘liquid’ here is slightly misleading. A more accurate description of the consistency of the earth’s mantle just below the crust is more like that of a taffy that is sticky enough to grab a hold of the rough and uneven underside of the crust and pull the crust along with it. This constant tugging at the underside of the crust by a thick, sticky substance sometimes results in separation or rupturing of the crust which might allow for the liquid rock to ooze through to the surface. But that story belongs in the  section onPlate Tectonics.

 

Creation of the Moon

Fitting right in with the Accretion Theory, the Giant Impactor Theory suggests that an object the size of Mars hit the still- forming Earth 4.5 billion years ago. When this object hit, it sent large abounts of superheated       material from          (Click on the image for a closer look.)
the outer layers       Image Credit: William K. Hartmann
of both bodies into
orbit around the Earth. This molten debris formed a ring around the Earth. The debris in the ring eventually stuck together to form the Moon. Supporting evidence for this theory includes:

• a lunar orbit that is slightly tilted in respect to Earth’s equator (An Earth and Moon that developed together side by side would most likely have had the Moon orbiting right over the earth’s equator.  Actually, this would have been cool because there would have been a lunar and a solar eclipse every month!  However, due to the slight orbital tilt of the Moon, most times the Moon travels above or below the Sun as seen from Earth – so no solar eclipses, or it travels above or below Earth's shadow in space - so no lunar eclipses each month either.  As a result, eclipses only happen once in a while when the Earth, Moon and Sun line up just right, as opposed to every month.);

• the Moon is moving away from the Earth at the rate of about an inch a year. As a result, the Moon is about a yard farther away from the Earth now than when Neil Armstrong walked on its surface;

Lunar rocks are very similar to some Earth rocks.  This is most likely the result of some material from both bodies in the collision mixing together.