HEAT AND NUCLEAR ENERGY

Heat energy is transferred from one body to another as the result of a difference in temperature. If two bodies at different temperatures are brought together, energy is transferred--i.e., heat flows--from the hotter body to the colder. The effect of this transfer of energy usually, but not always, is an increase in the temperature of the colder body and a decrease in the temperature of the hotter body. A substance may absorb heat without an increase in temperature by changing from one physical state (or phase) to another, as from a solid to a liquid (melting), from a solid to a vapour (sublimation), from a liquid to a vapour (boiling), or from one solid form to another (usually called a crystalline transition). The important distinction between heat and temperature (heat being a form of energy and temperature a measure of the amount of that energy present in a body) was clarified during the 18th and 19th centuries.

Nuclear energy, also called atomic energy, is released in significant amounts in processes that affect atomic nuclei, the dense cores of atoms. It is distinct from the energy of other atomic phenomena such as ordinary chemical reactions, which involve only the orbital electrons of atoms. One method of releasing nuclear energy is by controlled nuclear fission in devices called reactors, which now operate in many parts of the world. Another method for obtaining nuclear energy, controlled nuclear fusion, had not been perfected by the late 1980s. Nuclear energy has been released explosively by both nuclear fusion and nuclear fission.

Task 1. Use the following key words and word combinations to give the main ideas of the text.

1. Heat energy, to transfer, temperature difference.

2. The effect, energy transfer, an increase, temperature, a decrease, the colder/hotter body.

3. A substance, to absorb, heat, to change, a physical state.

4. Nuclear energy, to release, processes, to affect, atomic nuclei.

5. Nuclear energy, to releaser, reactors.

6. Nuclear energy, to obtain, controlled nuclear fusion.

Task 2. Complete the following sentences in accordance with the contents of the text.

1. Heat energy is transferred …

2. The effect of energy transfer is …

3. A substance that has absorbed heat …

4. Heat and temperature are different notions because …

5. Nuclear energy is released …

6. One method of releasing nuclear energy is …

7. Another method of obtaining nuclear energy is …

Task 3. Describe the forms of energy mentioned in the text.

Newton’s Three Laws of Motion (video film)

Watch the film and answer the following questions:

1. When did Newton live?

2. What did he develop?

3. Where were his laws of motion published?

4. What did Newton’s discoveries lead to?

5. What does the first law of motion state?

6. How can you explain that three spheres on the table remain in a state of rest?

7. What is inertia?

8. What magnitudes does the second law of motion connect?

9. What is acceleration?

10. What does it depend on?

11. How is the relationship between force, mass and acceleration expressed?

12. What does the 3^rd law of motion?

13. What example is given in the film to illustrate the 3^rd law?

14. Can you give your own examples of Newton’s laws of motion functioning from everyday life?

Date: 2015-01-12; view: 951