Different types of variables and examples of them
Independent Variable (IV)
Example 1
Three Redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The height of each tree is measured once a week.
Example 2
You wash three dirty shirts. One is washed with Tide laundry detergent, one is washed with Gain laundry detergent, and the last one is washed with only water. When you are finished, you check to see how clean the shirts are.
Example 3
You give three different concentrations of salt water to sunflower plants. After a two week period, the height is measured.
Independent Variable (IV)
- The part of the experiment that is different in each group.
- What you are testing (e.g. - different types of soap).
- The part of the experiment that changes as a result of the independent variable.
- What is measured (e.g. - how clean the shirt gets).
- Experimental group that is kept under normal conditions, or has no variable.
- What is normal (e.g. - tree grown outside).
- What has no variables (e.g. - no soap used).
Example 1
Three Redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The height of each tree is measured once a week.
- IV - Different humidity levels.
- DV - The height of each tree.
- CG - Tree outside in normal conditions.
Example 2
You wash three dirty shirts. One is washed with Tide laundry detergent, one is washed with Gain laundry detergent, and the last one is washed with only water. When you are finished, you check to see how clean the shirts are.
- IV - The different types of laundry detergent (soap).
- DV - How clean the shirts are.
- CG - The shirt washed without laundry detergent.
Example 3
You give three different concentrations of salt water to sunflower plants. After a two week period, the height is measured.
- IV - Concentrations of salt water.
- DV - The height of the sunflower plants.
- CG - None - A plant watered normally.