Across
- 3. a substance that reduces the transfer of heat.
- 7. economic activity concerned with the processing of raw materials and manufacture of goods in factories.
- 9. any of numerous greasy usually liquid substances from plant, animal, or mineral sources that do not dissolve in water.
- 10. A natural dark brown to black graphite like material used as a fuel, formed from fossilized plants and consisting of amorphous carbon with various organic and some inorganic compounds.
- 11. Processing used materials into new products.
- 14. a large natural or artificial lake used as a source of water supply.
- 15. a barrier that stops or restricts the flow of surface water or underground streams.
- 18. capable of being renewed.
- 20. molten or semi-molten natural material from which all igneous rocks are formed.
Down
- 1. fuel made from decomposing plants and animals.
- 2. the ability to do work or cause change; can be changed into different forms and can move between objects.
- 4. a device that can change the potential difference or voltage of an alternating current.
- 5. a machine for producing continuous power in which a wheel or rotor, typically fitted with vanes, is made to revolve by a fast.
- 6. Renewable energy from falling water or tides.
- 8. the introduction of contaminants into the natural environment that cause adverse change.
- 12. eliminated or discarded as no longer useful or required after the completion of a process.
- 13. type of fuel that is burned to produce heat and cook food.
- 16. cell A device that turns hydrogen into fuel.
- 17. a machine that converts kinetic energy into electrical energy.
- 19. energy generated from the burning of plants, wood, or agricultural waste.