Identifying Scientific Variables

Which variable is the one that is being measured in a scientific investigation?

• Dependent variable
• Independent variable
• Control variable

Which variable is the one that is used for comparison (not manipulated) in a scientific investigation?

• Dependent variable
• Independent variable
• Control variable

Different rose bushes are grown in a greenhouse for two months. The number of flowers on each bush is counted at the end of the experiment. Identify the dependent variable.

• The rose bushes
• Number of Flowers on each bush

Different rose bushes are grown in a greenhouse for two months. The number of flowers on each bush is counted at the end of the experiment. Identify the independent variable.

• The rose bushes
• Number of Flowers on each bush

You water three sunflower plants with salt water. Each plant receives a different concentration of salt solutions. A fourth plant receives pure water. After a two week period, the height is measured. Identify the dependent variable.

• Concentration of salt solution
• Plant height
• Fourth plant with pure water

You water three sunflower plants with salt water. Each plant receives a different concentration of salt solutions. A fourth plant receives pure water. After a two week period, the height is measured. Identify the independent variable.

• Concentration of salt solution
• Plant height
• Fourth plant with pure water

You water three sunflower plants with salt water. Each plant receives a different concentration of salt solutions. A fourth plant receives pure water. After a two week period, the height is measured. Identify the control variable.

• Concentration of salt solution
• Plant height
• Fourth plant with pure water

Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The heights of the trees are measured once a week. Identify the control variable.

• Humidity levels
• Height of tree
• Tree outside in normal conditions

Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The heights of the trees are measured once a week. Identify the dependent variable.

• Humidity levels
• Height of tree
• Tree outside in normal conditions

Three redwood trees are kept at different humidity levels inside a greenhouse for 12 weeks. One tree is left outside in normal conditions. The heights of the trees are measured once a week. Identify the independent variable.

• Humidity levels
• Height of tree
• Tree outside in normal conditions