three types of variables used in scientific experiments. The first variable type is called the independent variable. This variable is the one that is manipulated or changed by the scientist. The second type of variable is the one that is observed or measured in the experiment, and it is known as the dependent variable. You can remember this because the observation or measure of the dependent variable will change as the independent variable is altered.

Let's use an example that may assist you to understand these two types of variables. You have a plastic container with water inside. You place the container in a metal box and raise the temperature. Here, the temperature is the independent variable, so when you're adjusting the temperature, you're changing the independent variable. The water is the dependent variable. If there is a cause and effect relationship between water and temperature, then the water will change with the temperature change. And, of course, we know that the water will change from liquid into gas or steam with rising temperatures in the box.

But what about that third type of variable used in scientific experiments? It is the control variable, also known as the constant variable. As the name suggests, it is the variable that the scientist wants to remain the same.