Across
- 5. (adj) stopping and starting often and for short periods
- 6. (adj) using the power of the sun’s light and heat
- 7. (n) a colourless gas that is the lightest of all gases
- 9. (adj) able to continue without causing damage to the environment
- 12. (n) the smallest part of an element that can exist alone or can combine with other substances to form a molecule
- 17. (v) to make air, water, soil etc dangerously dirty and not suitable for people to use
- 20. (adj) replaces itself naturally, or is easily replaced because there is a large supply of it
- 21. (n) the hot mist that water produces when it is boiled
- 22. (n) the production by a green plant of special substances like sugar that it uses as food, caused by the action of sunlight on chlorophyll
- 24. (v) to take in liquid, gas, or another substance from the surface or space around something
- 25. (n) the process of working on a new product, plan, idea etc to make it successful
- 26. (n) a very small piece of matter with a negative electrical charge that moves around the nucleus
- 30. (n) the repairs, painting etc that are necessary to keep something in good condition
- 31. (n) the process of separating a liquid into its chemical parts by passing an electric current through it
Down
- 1. (n) a machine with an engine that is used to take people or things from one place to another
- 2. (n) a very short electric wave that is used in cooking food and sending messages by radio, and in radar
- 3. (adj) not real or not made of natural things but made to be like something that is real or natural
- 4. (n) the flat wide part of an object that pushes against air or water
- 8. (adj) works well without wasting time, money, or energy
- 10. (n) a machine that produces electricity
- 11. (n) a small piece of metal or a wire that is used to send electricity through a system or through a person’s body
- 13. (adj) uses a reaction, involving the splitting of atoms, to produce very high temperatures and a very powerful explosion
- 14. (n) plant and animal matter used to provide power or energy
- 15. (n) a particular place, especially in relation to other areas, buildings etc
- 16. (adj) concerning or affecting the air, land, or water on Earth
- 18. (v) to make something become warm or hot
- 19. (n) something additional that is produced during a natural or industrial process
- 23. (n) the condition of having a paid job
- 27. (n) an engine or motor in which the pressure of a liquid or gas moves a special wheel around
- 28. (n) unwanted materials or substances that are left after you have used something
- 29. (n) a layer of a mineral, metal etc that is left in soil or rocks through a natural process