Variables in a scientific experiment are the different factors or aspects that can change and have an effect on the outcome of the experiment. They're like the pieces of a puzzle that scientists try to put together to understand how things work. There are typically three main types of variables in an experiment: independent variables, dependent variables, and controlled variables (also known as constants).
Independent Variable: This is the variable that the scientist deliberately changes or manipulates in the experiment. It's the "cause" that you're testing to see how it affects something else. For example, if you're testing how different amounts of sunlight affect plant growth, the amount of sunlight would be the independent variable because you're controlling it to see how it affects the plants.
Dependent Variable: This is the variable that you're observing and measuring to see how it responds to the changes in the independent variable. It's the "effect" that you're interested in. In the plant growth example, the height of the plants would be the dependent variable because you're measuring how it changes based on the different amounts of sunlight.
Controlled Variables (Constants): These are the variables that you intentionally keep the same throughout the experiment. You want to make sure that only the independent variable is causing changes in the dependent variable. If you're testing plant growth, you might keep things like the type of soil, the size of the pots, and the temperature the same to isolate the effect of sunlight.
By carefully controlling and measuring these variables, scientists can make more accurate conclusions about cause and effect relationships in their experiments. It's like figuring out which puzzle pieces fit together to give you the full picture of what's happening.