Natural Science

7. a chemical reaction that happens in some living things, such as yeast and bacteria.
9. the flow of electrical charges through materials.
11. a material which does not allow electrical charges to move.
13. a method used to separate substances of different density in heterogeneous mixtures.
15. another word for a homogeneous mixture.
17. a chemical reaction that happens when some metal substances such as iron combine with oxygen in the presence of water.
18. A connecting wire, usually made of copper, wrapped in plastic covering.
19. a device with a magnetic needle that always points north. We use it to orient ourselves.
21. the component of an electric circuit which provides the electricity.
22. the component of an electric circuit which transforms electricity into another type of energy.
23. a mixture in which the different components can be distinguished.

1. a method used to separate solids from liquids, or solids with different size particles, in heterogeneous mixtures.
2. a method used to separate liquids that have different boiling points in homogeneous mixtures.
3. a type of matter which contains only one type of component.
4. an object which can attract other objects made of iron and other magnetic metals.
5. a closed path through which electricity flows.
6. These happen when atoms react and group together differently.
8. a type of matter which contains two or more pure substances.
10. a method used to separate solids from liquids in homogeneous mixtures.
12. a material which allows electrical charges to move.
14. a mixture in which the different components cannot be distinguished.
16. a chemical reaction that happens when objects or substances are burned.
20. the force of attraction exerted by magnets.