My Science School

Using the Earth

People everywhere - including you and your family - are using the earth and its resources daily. Look around and see.

There is no question that Earth has been a giving planet. Everything humans have needed to survive, and thrive, was provided by the natural world around us: food, water, medicine, materials for shelter, and even natural cycles such as climate and nutrients. Scientists have come to term such gifts ‘ecosystem services’, however the recognition of such services goes back thousands of years, and perhaps even farther if one accepts the caves paintings at Lascaux as evidence. Yet we have so disconnected ourselves from the natural world that it is easy—and often convenient—to forget that nature remains as giving as ever, even as it vanishes bit-by-bit. The rise of technology and industry may have distanced us superficially from nature, but it has not changed our reliance on the natural world: most of what we use and consume on a daily basis remains the product of multitudes of interactions within nature, and many of those interactions are imperiled. Beyond such physical goods, the natural world provides less tangible, but just as important, gifts in terms of beauty, art, and spirituality.

Earth Day seems as good a day as any to remind ourselves what nature gives us free-of-charge. 

We all need water to survive. People use the earth’s water to drink and to wash. They use it to grow crops. They fish its oceans, lakes, and rivers.

People use the land. They farm the land to grow food. They clear land to build homes and roads. They mine the land for such minerals as coal, iron, and gold.

People enjoy the earth. They grow gardens and make parks. They go swimming and sailing.

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The earth is full of natural resources - water, air, and land. The earth is also full of life - plants, animals, and people.

We all depend on the water, air, land, plants, and animals to live. So, it is important for people to protect the earth and everything on it.

Our Earth is the only planet with the continuity of life so it becomes more and more important to generate a sense of urgency of saving our mother earth from all sorts of planet harming activities. Our mother earth needs to be saved as our survival depends completely on this planet. It is our responsibility to raise awareness about saving our mother earth.

Earth provides every resource for sustaining living things and inanimate things. Our planet harming activities are resulting in causing an irreversible damage to the environment which results in degrading the condition of this planet. By taking care of this planet, we can improve our well-being as healthy environment will help in improving the quality of our life. It is our collective responsibility to raise public responsibility regarding the well-being of our mother earth.

Saving our earth and its environment becomes highly important as it provide us food and water to sustain life. Our well-being solely depends on this planet it gives food and water to all living things to it is our responsibility to take care of it.

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Climate is important to people, plants, and animals. It makes a difference in where and how people live and work. It affects the amount of food that can be grown to eat. But did you know that there are things that can change the climate? Natural events and people can cause long-term changes in the climate.

One natural event that can change the climate is a volcano. When a volcano erupts, it throws huge amounts of dust into the atmosphere. The dust may stay in the air for many years, scattering the sun’s rays and blocking sunlight from the ground. So a volcanic eruption may actually cool parts of the earth.

The actions of people have also changed the climate. The climates of areas that are now cities have become warmer than nearby land. This is because large buildings, streets, and pavements hold heat. Also, pollution slows water vapour from rising into the atmosphere, so most cities have a slightly wetter climate, too.

Some places are warm almost every day of the year. Other places are mostly cool and rainy. Other places have changing seasons - spring, summer, autumn, and winter.

Climate is what the weather is like in the same area over a long period of time. Climate and weather are not the same thing. Weather is what happens in the atmosphere over a short period of time.

The sun, the ocean, and the land all help to make a climate. At the North and South poles, the climate is cold because the sun’s rays shine at an angle. Angled rays are not as strong as direct rays.

Near the equator, the sun’s rays shine almost straight down. So the climate of most countries near the equator is very warm or hot.

Warm parts of the ocean near the equator often have the wettest climate. This is because in these places the air absorbs the greatest amount of moisture, and it falls as rain.

Sometimes the climate of mountains is cooler than the land around them. In these higher places, warm air rises and cools rapidly. Some parts of mountains are also wetter because warm air is moist. As the warm air rises, it quickly cools. The cool air can’t hold a lot of water, so it falls as rain.

Weather Watchers

Everyone is a weather watcher, but almost no one knows how hot, how cold, or how wet it will be tomorrow or next week. But meteorologists can predict the weather.

A meteorologist is a scientist who studies the earth’s atmosphere and its weather and climate. Meteorologists are weather watchers or weather forecasters.

How do meteorologists predict the weather? They search for clues. They check the wind’s speed and direction. They record the temperature of the air, the air pressure, and the amount of water in the air.

Meteorologists also gather information from weather satellites in outer space. These satellites circle the earth and photograph clouds and any gathering storms. The pictures are then sent back to the earth.

Information also comes from weather stations on the earth’s surface. A type of radar called Doppler is used to study winds and storms. It can find approaching storms more than 320 kilometres away from the station.

Meteorologists gather weather reports from all over the world. They use this information to draw weather maps. They also use computers to make forecasts. You hear their forecasts every day on television or over the radio. But since the weather changes quickly sometimes, meteorologists usually update their forecasts.

Dark clouds gather and a thunderstorm begins. The patter of rain grows louder and louder. Suddenly, something is pounding on the roof. That “something” is hail.

Hail is lumps of ice and snow. Usually the hailstones look like little beads, but they may be as big as golf balls - or even larger!

Hailstones begin as frozen raindrops in a rain cloud. Wind carries them to a part of the cloud that has some extra cold water drops. Some of the drops land on the already frozen drops, causing them to freeze also.

The frozen drops grow larger as more water drops freeze onto them. This continues as long as an upward wind can support them. The wind keeps them in contact with the extra cold water in the cloud.

Sometimes the wind will slow, and the hailstones will start to fall. But a gust will lift them back up to the extra cold part of the cloud, where they grow even more. Finally, they are so heavy, the wind cannot lift them. The hailstones fall and you can hear them hitting roofs, grass, and pavements.

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Take a close look at some snowflakes. You can see that they aren’t drops, like rain; or lumps, like hail; or tiny beads, like sleet. They look more like little feathers.

Snow forms when water vapour in clouds freezes. It forms at the top of storm clouds where the air is colder. The frozen water drops grow as more water vapour freezes onto them. They turn into tiny, clear pieces of ice called snow crystals. A snowflake is actually a bunch of snow crystals.

When you look at a snowflake through a magnifying glass, you see a beautiful, lacy shape. Even when they may seem the same, no two snow crystals are exactly alike. Some are flat. Others are shaped like long needles. Most look like pieces of lace. Yet, in one way they are almost all the same. Almost all snow crystals have six sides.

Snow can form high in the sky even in summer. But when snow falls in summer, it melts and becomes rain as soon as it reaches warm air lower down.

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Lightning and Thunder

A flash of light zigs and zags across the sky. Another flash zaps its way to the ground. A loud crack, boom, or rumble sounds soon after. The flash is lightning. The sound is thunder.

The flash we see when snakes through the sky lightning is really a huge electric spark. During a thunderstorm, each tiny drop of water in a cloud becomes electrically charged making the whole cloud charged. When this electrical charge becomes strong enough, it forms a huge electrical spark - lightning.

Lightning can travel in many ways. Sometimes a charge flashes from one place to another within a cloud. Other times, electricity rushes between two clouds with electrical charges. Also, lightning can strike the ground.

A flash of lightning heats up the air around it. The heated air spreads or rushes out in all directions. As it swells, it slams into cooler air, making it shake. This is what causes the sound of thunder.

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Long ago, people thought rainbows were magic. Some people believed a rainbow was a bridge that appeared in the sky when the gods wanted to leave heaven and visit the earth. Other people believed that if you could find the end of the rainbow - where it touched the earth - you would find a pot of gold.

Today we know that a rainbow is made by sunlight shining through drops of water. Sunlight looks white, but it is really made up of many colours. When sunlight enters a raindrop, it breaks up into lots and lots of colours, including violet, blue, green, yellow, orange, and red. We see these colours in the rainbow. But because the colours blend, we usually see only four or five of them.

For you to see a rainbow during a rain shower, the sun must be behind you, and the rain must be somewhere in front of you. Rays of sunlight break up into colours as they reflect off many drops of falling rain. Together they make a shimmering, curved, colourful rainbow. If the rain is heavy, one or both ends of the rainbow may appear to touch the earth, many kilometres apart.

Some rainbows form when it isn’t raining. Sometimes small rainbows appear in waterfalls, in sprays of water from the sea, or in fountains where the water shoots high.

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Rain is recycled

Rain falls from clouds, but the water in the clouds comes from water on the earth. How does that happen?

The earth is covered with water - in lakes, streams, ponds, rivers, puddles, and huge oceans. Even the earth’s plants and animals have water in them.

Every day, the sun dries up huge amounts of this water, turning it into vapour. The warmth makes the vapour rise. It rises so high that it cools and forms clouds made of water and ice drops. As the drops get larger, they become too heavy to stay in the air. They fall as rain or snow.

Some of the rain and snow soaks into the soil and is used by plants. Some collects in streams or rivers that flow into the ocean. The sun warms it up and turns it into water vapour again. This water cycle happens over and over. The earth is always recycling its water!

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Weather

Somewhere on the earth right now, it is cloudy and rainy. Somewhere it is sunny. Somewhere it is dark, windy, and snowing.

What is the weather like today where you are? Is it raining? Does it look as if it’s about to snow? Is the sun shining?

Do you ever talk about the weather? Many people do. Almost everyone cares about the weather.

The weather affects us in many ways. Day-to-day changes in weather can influence how we feel and the way we look at the world. Severe weather, such as tornadoes, hurricanes, and blizzards, can disrupt many people’s lives because of the destruction they cause.

Weather doesn’t just stay in one place. It moves, and changes from hour to hour or day to day. Over many years, certain conditions become familiar weather in an area. The average weather in a specific region, as well as its variations and extremes over many years, is called climate.

There are six main components, or parts, of weather. They are temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness. Together, these components describe the weather at any given time. These changing components, along with the knowledge of atmospheric processes, help meteorologists - scientists who study weather - forecast what the weather will be in the near future.

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Eeee-rump! Eeee-rump! The sound of a foghorn echoes in the night. A thick, grey fog creeps in from the ocean and settles over the waterfront. You can hardly see your hand in front of your face. It seems as if you are in the middle of a cloud.

As a matter of fact, that’s just what fog is. It’s a cloud of tiny water drops that touches the earth, instead of floating high in the sky.

Like every other kind of cloud, fog forms when warm, moist air meets cool air. Fog often forms when warm, moist air passes over the cold water or an ocean, lake, or river. The warm air quickly cools. Then the water vapour in it becomes millions of tiny drops - a cloud that rolls in from the water and spreads out over the land.

Fog forms over the land in much the same way when ground that has been warm all day begins to cool off. As the warm air above the ground cools, the water vapour in the air turns into tiny drops of water. A fog hugs the ground.

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Clouds sometimes look like gobs of whipped cream in the sky. Sometimes they look like soft feathers. But what are clouds?

Clouds are billions and billions of tiny drops of water or ice crystals clustered together. Some clouds are all water, some are all ice, and some are a mixture.

You might think the water drops and ice crystals would be so heavy they would fall to the ground. But they are so tiny that the air holds them up, and breezes keep them floating in the air.

The water that makes clouds comes from the earth. Every day, the heat of the sun dries up tonnes of water from everywhere on the earth. All this water is turned into water vapour, which is water in the form of gas. This gas floats up into the air. But as it rises higher and higher, it begins to cool. When it cools enough, it turns back into water or ice. Then, tiny drops form around tiny, tiny bits of dust in the air. These drops make up the clouds.

There are many different kinds of clouds, and each kind has a name. Most clouds are named after their shape.

The clouds that look like great sheets pulled across the sky are called stratus clouds. These are the kinds of clouds that are closest to the ground. They form when a layer of warm air rolls over a layer of cooler air. Together they form a thick sheet-like layer.

The clouds that look like fluffy balls of cotton or scoops of ice cream are called cumulus clouds. Cumulus clouds that rise high into the air and grow dark and heavy with rain are the kinds of clouds that cause thunderstorms.

The highest clouds of all look like thin, wispy streaks or curls. They are so high up in the air, where the air is cold, that they are made of ice droplets. These clouds are called cirrus clouds.

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A thick, dark cloud forms in the sky. Warm air from near the earth rises rapidly towards the cloud. At the bottom of the cloud, the air starts spinning. This wind spins and twists and drops down into the shape of a long tube, or funnel. This wind is called a tornado, or twister.

The funnel may touch the earth’s surface. When a tornado touches ground, it can be dangerous. It can pick up heavy machinery and toss it far. The winds of a tornado rip roofs from houses and uproot large trees.

Tornadoes can happen in many parts of the world. But most tornadoes happen over the central U.S.A. People have recorded whirlwinds about 480 kilometres per hour there.

A tornado is a whirling wind that reaches down from the clouds and touches the ground. But dust devils and sand pillars are whirling winds that go from the ground up into the sky. They are much smaller than a tornado.

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