Bliv Klog

Mills and power from water

Mills and power from water

Until pumps and mill wheels were invented to make use of water energy, it was difficult to transport water – especially if you did not have an ox or donkey to hand. Go back in time and learn more about mills and water power.

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Kites in the sky

A kite flies because the wind pushes it

The wind exerts a force on the kite. You can feel this force when you stand with the kite in the wind. The wind pushes the kite (and you). The force can be so strong that you find it difficult to stand still. The wind will blow you away.

The wind also pushes the kite when it flies. It cannot blow the kite away as the kite is tied to the string. But the wind can blow the kite up into the air because the kite is at a slight angle to the wind.

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Joules and watts

Joules and watts

Accumulate a source of energy over time and build an energy supply.

It is like filling a bucket with water from the tap. The water runs at a rate of 10 litres per minute. After one minute, the bucket contains 10 litres of water.

When we switch on the bicycle light, the opposite happens.

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Thunder and lightning

Thunder and lightning

Lightning is only a few centimetres in diameter but has a brightness equivalent to 1 million 100-watt bulbs per metre and a temperature of up to 30,000 degrees.

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The universe

The universe

Our universe includes planets, moons, stars and galaxies and is thought to have been created approximately 13.7 billion years ago.

We live in the galaxy known as the Milky Way, which can be seen from Earth on clear, starry nights. There are billions of solar systems in our galaxy and one of them is our very own solar system. This has eight planets, with our planet, Earth, the third in the row. As far as we know, the Earth is the only known planet on which life is found.

See the video below and take a trip through our universe.

 

 

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Volcano

Volcano

Imagine that the Earth’s crust is a very thin skin on top of a large ball of molten rock. Like a puzzle, the Earth’s crust is made up of multiple parts called tectonic plates. These can be different sizes, but are mainly the size of continents and move very slowly (only 1 – 9 cm per year).

Where the plates crash into each other are the areas of the Earth where volcanoes, earthquakes and geysers are found.

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Glacier

Glacier

What is a glacier?

Simply put, a glacier is an old river of ice. Some are small, river-like alpine glaciers that are found high up in mountains, while other are massive flows of inland ice such as those seen on Antarctica and in Greenland.

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Geyser

Geysers and volcanic activity

In areas of volcanic activity, where hot magma is close to the Earth’s surface, geysers are often found.

Geysers are mostly little air pockets in the Earth’s surface which are associated with one or more narrow chutes that lead down into a large underground pool of water. Water gradually seeps down through the ground until it reaches the hot floor. This then heats up the water.

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Solar energy

The sun bathes us in energy

The sun makes roses and rainforests grow

It warms our body and makes the sea evaporate so that clouds can rain. It is only in the last few years that we have begun to tame its rays.

Today, there are two main ways that we tame solar energy:

With solar heating panels, which can make warm water, and with solar cells that can make electricity. The sun gives us lots of energy but it is unstable. At night or when it is cloudy we cannot tap its energy.

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Wind energy

Wind energy

Who tickles your cheek today and batters trees or spreads forest fires tomorrow? The wind of course! This can be both gentle and biting. When it wants to, it can easily turn a wind turbine’s large, heavy blades.

A wind turbine requires enormous amounts of air to turn.

The blades constantly circle round. If the diameter of the blade circles is over 54 m, then the wind turbine covers an area of 2,290 m2. That is half a football pitch!

A strong gale of 15 metres per second pushes 42 tonnes of air through this blade area.

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