Things you need to know about Science

Subject: Things you need to know about Science Mon Feb 16, 2009 11:04 pm

Facts about Earth

1. The speedy Space ball

* The Earth is a huge ball of rock moving through space at early 3000 metres per second. it weighs 6000 million, million tonnes. Up to two-thirds of the earth's rocky surface is covered by water - this makes the seas and oceans. Rock that is not covered by water makes the land. Surrounding the Earth is a layer gases called the atmosphere (air). This reaches about 700 kilometres from the Earth's surface - then space begins.

2. Where did the Earth came from?

* The Earth came from a cloud in space. Scientists think that Earth are formed from a huge cloud of gas and dust around 4500 million years ago. A star near the cloud exploded, making the cloud spin. As the cloud spun aroundthe sun and stuck together to form lumps of rock. In time the rocks crashed into each other to make planets. The Earth is one of these planets.

(Clouds of gas and dust are made by the remains of old stars that have exploded or simply stopped shining. It is here that new stars and their planets are form.)

* At first the Earth was very hot. as the rocks crashed together they warmed each other up. Later, as the Earth formed, the rocks inside it melted. The new Earth was a ball of liquid rock with a thin, solid shell.

* Huge numbers of large rocks called meteorites crashed into Earth. they made round hollows on the surface. These hollows are called craters. The moon was hit with rocks at the same time. look at the Moon with binoculars - you can see that were made long ago.

(Erupting volcanoes and fierce storms helped form the atmosphere and oceans. these provided energy that was needed for life on Earth to begin.)

* The oceans and seas formed as the Earth cooled down. Volcanoes erupted, letting our steam, gases and rocks from inside the Earth. As the Earth cooled, the steam changed to water droplets and made clouds. As the Earth cooled further, rain fell from the clouds. It rained for millions of years to make the seas and oceans.

(Millions of rocks crash into Earth as it speeds through space. Some larger ones may reach the ground as meteorites.)

3. In a Spin

* The Earth is like a huge spinning top. In continues to spin because it was formed from a spinning cloud of gas and dust. it does not spin straight up like a top but leans a little to one side. The Earth takes 24 hours to spin around once. We call this period of time a day.

* The Earth's spinning makes day and night.. each part of the Earth spins towards the Sun, and then away from it every day. When a part of the Earth is facing the Sun it is night-time.

(If you were in space and looked down on Earth from the North Pole, it would seem to be moving anticlockwise.)

* The Earth spins around its Poles. The Earth spins around two points on its surface. They are atopposite ends of the Earth. One is on top of the Earth. It is called the North Pole. The other is at the bottom of the Earth. It is called the South Poles are so cold, they are covered by ice and snow.

(The Earth moves around the Sun in a path called an orbit. it takes a year to make this journey. in that time it spins round 365 and a quarter times.)

* The Spinning Earth acts like a magnet. At the centre of the Earth is a liquid iron. As the Earth spins, it makes the iron behave like a magnet with a North and South Pole. These act on the magnet in a compass to make the needle point to the North and South Poles.

4. Inside the Earth

* There are different parts of the Earth. There is a thin, rocky crust, a solid middle called the mantle and a center called the core. The outer part of the core is a liquid but the inner core is made of solid metal.

* At the centre of the Earth is a huge metal ball called the inner core. It is 2500 kilometres wide and is made mainly from iron, with some nickel. the ball has an incredible temperature of 6000 (degree) celsius - hot enough to make the metals melt. They stay solid because other parts of the Earth push down heavily on them.

* Around the centre of the Earth flows a hot, liquid layer of the Earth flows a hot, liquid layer of iron and nickel. this layer is the outer core and is about 2200 kilometres thick. As the Earth spins, the metal ball and liquid layer move at different speeds.

* The largest part of Earth is a layer called the mantle, which is 2900 kilometres thick. It lies between the core and the crust. Near the crust, the mantle is made of slow-moving rock. When you squeeze an open tube of toothpaste moves a little like the rocks in the upper mantle.

* The Earth's surface is covered bythe crust. Land is made of continental crust between 20 and 70 kilometres thick. Most of this is made from a rock called granite. The ocean bed is made of oceanic crust about 8 kilometres thick. It is made mainly from a rock called basalt.

* The crust is divided into huge slabs of rock called plates. Most planets have land and seas on top of them but some , like the Pcific Plate, are mostly covered by water. The large areas of land on the plates are called continents. There are seven continents - Africa, Asia, Europe North America, South America, Oceania, and Antarctica.

* Very very slowly, the continents are moving. Slow-flowing mantle under the crust moves the plates across the Earth's surface As the plates move, so do the continents. In some places, the planets push into each other. In others, they move apart. North America is moving 3 centimetres away from Europe every year!

Subject: Re: Things you need to know about Science Mon Feb 16, 2009 11:05 pm

Facts about Weather

* The Earth is wrapped in layers of gases called atmosphere. The
weather takes place in the lowest layer, the troposphere. The layer
above is the stratosphere. Aeroplanes fly here to avoid bad weather.
The mesosphere is the middle layer and above it is the thermosphere.
The exosphere is about 700 kilometres above your head.

* Clouds are maid in the air above the oceans.When
the Sun shines on the water's surface, some evaporates. A gas called
water vapour rises into the air. As the vapour cools, it forms clouds
which are blown all over the Earth's surface. the clouds cool as they
move inland, and produce rain. Rain falls on the land, then flows away
in rivers back to the oceans. We call this process the water cycle.

* A hurricane is a destructive storm which gathers over a warm part of the ocean.
Water evaporating from the ocean forms a cast cloud. As cool air rushes
in below the cloud , it turns like a huge spinning wheel. The centre of
the hurricane (the eye) is completely still. But all around, winds gust
at speeds of 300 kilometres an hour. If it reaches land the hurricane
can blow buildings into pieces.

* A tornado is the fastest wind on Earth - it can spin at speeds 500 kilometres an hour. Tornadoes
form over ground taht has become very warm . Fast-rising air makes a
spinning funnel which acts as a vacuum cleaner. it can devastate
buildings and lift up cars and traffic, flinging them to the ground.

*Snowflakes form in the tops of clouds. It
is so cold here taht water freezes to make ice crystals. As the
snowflakes get larger, they fall through the cloud. If the cloud is in
warm air, the snowflakes melt and form raindrops. If teh cloud is in
cold air, the snowflakes reach the ground and begin to settle.

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Subject: Re: Things you need to know about Science Mon Feb 16, 2009 11:39 pm

Facts about the Power of Lasers

* Laser Light is a special kind of light. Like ordinary light, it is made of waves, but there are three main differences. First, ordinary white light is a mixture of colors. Laser light is just one pure color. Second,ordinary light waves have peaks (highs) and troughs (lows), which do not line up with each other - laser light waves line up perfectly. Third, an ordinary light beam spreads and fades. A laser beam does not. It can travel for thousands of kilometres as a strong, straight beam.

* To make a laser beam, energy is fed in short bursts into a substance called the active medium. The energy might be electricity, heat or ordinary light. In a red ruby laser, the active medium is a rod of ruby crystal. A strong lamp makes the tiny particles in the crystal vibrate.They give off energy, which bounces to and fro inside the crystal, off the mirrors at at each end. eventually, the rays vibrate with each other and they are all the same length. The energy becomes so strong that it bursts through a mirror at the end of the crystal.

* Lasers were invented in 1960. They are used to play CDs and DVDs for music and movies, and in computers. They cut through thick metal in factories, and carry out delicate eye operations. They carry phone calls and television programmers along cables. they even measure movements of the Earth to warn volcanoes or earthquakes.

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Subject: Re: Things you need to know about Science Tue Feb 17, 2009 12:00 am

Facts about Riding the Waves

*The first sea sport was surfing. it took off in the 1950's but was invented centuries earlier in Hawaii. Hawaii is still one of the best places to surf - at Waimea Bay, surfers catch waves that are up to 11 meters high. The record for the longest rides, though, are made off the coast of Mexico, where it is possible to surf for more than one-and a half kilometers.

(Modern surfboards are made of super-light materials. This means they create little drag in the water - and the surfer can reach high speeds!)

* A single boat towed 100 waterskiers! This record was made off the coast of Australian in 1986 and no one has beaten it yet. The drag boat was a cruiser called Reef Cat.

* Three hulls are sometimes better than one. Powerboating is an exciting, dangerous sport. Competitors are always trying out new boat designs that will race even faster. Multi-hulled boats minimize drag, but keep the boat steady. Trimarans have three slender, streamlined hulls that cut through the water.

* Jetskiers can travel at nearly 100 kilometres per hour. Jetskis were developed in the 1960s. Their inventor was an American called Clayton Jacobsen who wanted to combine his two favourite hobbies, motorbikes and waterskiing. Today, some jetskiers are professional sportspeople.

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Subject: Re: Things you need to know about Science Fri Feb 20, 2009 9:31 am

miss ko na sineskwela.

Subject: Re: Things you need to know about Science Fri Feb 20, 2009 2:59 pm

holyshred wrote:

miss ko na sineskwela.

. . .ako din. . . miss ko na mag-aral sa undergrad. . . . . .

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