What is energy

energy

Energy is something like a force that can make a difference. That is exactly what the Greek expression means. A battery contains energy with which we can operate a device. The sun provides energy that warms our skin.

Energy can change from one kind to another. The electrical energy in a battery becomes sound energy that emanates from the loudspeaker. A person converts the chemical energy from food into kinetic energy in his stomach.

What types of energy are there in physics?

Water in a reservoir in the mountains contains a lot of energy due to its location. It could flow down and drive a water wheel. The scientists call this "potential" energy. This means something like "possible" energy.

When the water flows, it contains a lot of energy again. The scientists call this "kinetic" energy. This is the energy of movement. The water can drive a water wheel or a turbine. Kinetic energy also contains a moving car or train. In the event of an accident, it becomes very visible.

The turbine, in turn, can drive a generator and generate electricity. This is then the electrical energy. This can also achieve a lot again. You can use it to turn on lights, drive a motor and much more.

The sun provides light energy. The rays of light heat all things, the dark things more than the light ones. The sun causes the plants to grow. This happens in the green parts of the plant.

Wood, coal and oil also contain a lot of energy. It is called chemical energy. When you burn these substances, a lot of heat is generated. Again, this is a form of energy. The interior of the earth is also very hot. This is also a heat energy. It is called geothermal energy.

Atomic energy is a special type of chemical energy. In a nuclear power plant, thermal energy is generated from a heavy metal, uranium. An atom bomb also works like this: There the energy changes very suddenly and not only generates heat, but also pressure.

When you heat water on a fire, it starts to steam. We know that from the pressure cooker on the stove. The steam then flows out of the valve with pressure and makes a whistle or a hiss. So pressure is also a form of energy.

How do people use the various energies?

Humans have long used the energy of fire to warm themselves.

Humans cannot produce energy, but neither can they consume any. There is energy in the cosmos, and always the same amount overall. However, one can convert energy from one type to another. This happens in a power plant, but also in a machine, a lamp, a loudspeaker and so on.

People need warmth in order to be able to live comfortably in winter. It therefore burns natural gas, oil, coal or wood. We call this a heater. But bricks, bricks and glass are also made with a lot of heat. A lot of thermal energy is also required for baking and cooking.

We also need a lot of energy for movement: petrol makes a car drive. Petrol comes from petroleum. It's almost the same with an airplane. The mixer, on the other hand, makes the movement out of electrical energy. The windmill uses the power of the wind to drive the millstones.

Electricity is a very practical form of energy: in the lamp it becomes light, in the loudspeaker it becomes sound, in the mixer it becomes movement. Industrial robots need electricity to assemble parts of cars. The production of aluminum also requires a lot of electricity.

Is there always enough of any kind of energy?

The rotor of a wind turbine is assembled.

The sun is shining every day. So there will be enough solar energy for millions of years. That is why it is also called “renewable energy”. Hydropower is therefore also called a renewable energy: the sun allows sea water to evaporate. This collects in the clouds and rains down again.

Geothermal energy is also one of the renewable energies. It doesn't really renew itself, but there is very, very much of it. If a person uses some of it, it is so little that it cannot be measured at all.

Wood is also one of the renewable energies because it can grow again. It is also called a "renewable raw material". You should only get as much wood out of a forest as will grow back. This is called "sustainable management".

There is only a limited amount of coal, oil and natural gas. They were formed many millions of years ago, at the time of the dinosaurs and even before that. Dead plants were inundated by the sea and covered with earth. In a long, long time it became coal, oil and natural gas, the so-called fossil fuels. Once people have fetched all of it from the earth, it is gone.

In Europe and North America, people have already mined a lot of it. Today a lot of oil is extracted in Saudi Arabia and Iran, for example. These countries have a lot of money because of oil and can use the money for their own purposes.

The scientists make various calculations, but one thing is clear: if we continue to consume as much oil and gas as we do now, it will not be enough for a whole century. Then the supplies are used up for all time. They are also called “non-renewable energy sources”.

What problems are there with some energy sources?

In the years after 1800 the industrial revolution took place. People built large factories and have been able to make a lot more things since then. Instead of wood or charcoal, they mostly burn coal, crude oil or natural gas in industry.

Running out of these energy sources is not the only problem: there is a lot of carbon in coal, oil and gas. When it is burned, it produces carbon dioxide, which is also known as CO2, read: Ce-o-two. There is always more of that in the air. That is why temperatures are rising all over the world. This is called "global warming". For this reason, Germany has already shut down many coal-fired power plants.

Nuclear energy is not "renewable" either. For this you need uranium or other substances that can be extracted from the earth. Nuclear waste is generated in the nuclear power plants. These emit strong radiation. You don't see these radiations, but they make all living beings sick or even kill them. The nuclear waste is stored in certain places around the world, including Germany and Switzerland. Scientists are still looking for a safe place to put it. But since uranium still emits dangerous radiation for over 700 million years, this security cannot be guaranteed for such a long time.

In addition, atomic energy is very dangerous. In 1986 a nuclear power plant exploded in the Soviet city of Chernobyl, which is now in Ukraine. In 2011, a tsunami destroyed the nuclear power plant in Fukushima, Japan. Both areas are no longer allowed to enter today because of the radiation.

  • Windmills have been using wind energy for a long time.

  • Oil tankers during loading