When conducting an investigation, we often observe or make measurements of things that change. These are variables. Keeping track of variables in an experiment is important because it helps you analyze and understand your results. Remember from the experiment your class conducted in Lesson 2, there are two major types of variables . An independent variable is not affected by the other variables in an experiment . It is often something that a scientist changes in order to do an experiment . Experiments should have only one independent variable . A dependent variable depends on other factors in the experiment . It is often the thing we are trying to learn more about and is the experimental results . A third type of variable is a controlled variable . This is what a scientist keeps similar in all parts of the experiment . There are often multiple controlled variables . Scientists try to make sure that controlled variables do not affect the outcome or results of an experiment . In the explore section of your text, you conducted several experiments on the phase changes of water.

1.What was the independent variable in these experiments?

2.What was the dependent variable?

3.What were the controlled variables, or the things you tried to keep the same in each part of the experiments.