7.1 Answer the following questions

1. What is nuclear energy?

2. Why is mankind interested in nuclear energy?

3. Where is nuclear energy used?

8 Solar energy

Solar energy is energy directly from the Sun. This energy drives the climate and weather and supports virtually all life on Earth. Heat and light from the sun account for most of the available flow of renewable energy.

Solar energy technologies harness the sun’s energy for practical ends. These technologies began from the time of the early Greeks, Native Americans and Chinese warmed their buildings by orienting them toward the sun. Modern solar technologies provide heating, lighting, electricity and even flight.

Solar power is used synonymously with solar energy or more specifically to refer to the conversion of sunlight into electricity. This can be done either through the photovoltaic effect or by heating a transfer fluid to produce steam to run a generator.

Solar photovoltaics provide 0.04% of the world’s energy usage.

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8.1 Read the following international words: modern, energy, practical, technology, electricity, specifically, transfer, generator.

9 Electricity

The electric charge is also called electricity. We can generate electricity to illuminate our cities or we can store it in a battery to transport it. Electricity is a flow of electrons through a conductor. Copper is a good conductor so we use it in electric wires.

A simple electric circuit includes a battery with chemical paste, a carbon rod, a wire and a light bulb. The chemical paste contains an excess of electrons so when you connect the two poles of the battery, the copper wire attracts electrons. The electrons in the chemical paste repel the electrons in the carbon rod and make them flow through the соpper wire. When they arrive at the filament inside the bulb, they produce heat and emit light. That is we say that light is a photoelectric effect.

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9.1 Answer the following questions

1. What is electricity?

2. Where and why do we use copper?

3. What does simple electric circuit include?

10 Magnets and electricity

In most objects, all of the forces are in balance. Half of the electrons are spinning in one direction; half are spinning in the other. These spinning electrons are scattered evenly throughout the object.

Magnets are different. In magnets, most of the electrons at one end are spinning in one direction. Most of the electrons at the other end are spinning in the opposite direction. This creates an imbalance in the forces between the ends of a magnet. This creates a magnetic field around a magnet. A magnet is labeled with North (N) and South (S) poles. The magnetic force in a magnet flows from the North pole to the South pole.

If you try to push the South poles together, they repel each other. Two North poles also repel each other. Turn one magnet around and the North (N) and the South (S) poles are attracted to each other. Just like protons and electrons, opposites attract. These special properties of magnets can be used to make electricity. Moving magnetic fields can pull and push electrons. Some metals, like copper have electrons that are loosely held. They can be pushed from their shells by moving magnets. Magnets and wire are used together in electric generators.

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