| A | B |
|---|
| dichotomous key | A classification key that has two choices at each step. |
| diffusion | Particles spread out and move from an area of high concentration to an area of low concentration. |
| electromagnet | A wire with electricity running through it that is wapped around a piece of iron. A magnetic field is created. |
| endothermic | A chemical reaction that requires energy to continue. Vinegar + baking soda is an example--the temperature goes down. |
| exothermic | A chemical reaction that releases energy. Rusting, the nitric acid and penny are examples. The temperature goes up. |
| universal law of gravitation | All objects that have mass exert an attractive force on each other. The amount of attraction depends on two things: the mass of the objects and the distance between them. |
| particle motion | Solid < liquid < gas |
| magnetic field | The area around the magnet where the force is exerted. The force is strongest at the poles. |
| phyiological adaptation | Over many generations through the process of natural selection, a species' characteristics change to become better suited for the environment. Examples: polar bears have thick, white hair and layers of blubber, fish have a streamlined shape. |
