A question about scientific investigation

Question

A student wanted to look at the affect of salicylic acid on plant growth. He sets up an experiment which groups of five plants are given 2, 4 and 6 milliliters (mL) of salicylic acid. He planted the same type of seeds in identical containers and left them together in full sunlight. He gave each plant the same amount of water and charted the growth of each plant stem.

What is the independent variable, dependent variable, constants and control???

Answer 1

The Independent Variable is the test variable that is manipulated intentionally by the student/scientist. For this investigation, the IV is the amount/presence of salicylic acid in each plant.

The Control is the test that is performed without the Independent Variable: In this case, the plant that is tested under the same conditions with 0mL of salicylic acid.

The Dependent Variable depends on the Independent Variable. We look at what is being impacted by the change of the IV. The investigation states that the student is looking at the impact of the salicylic acid ON plant growth. The Dependent Variable would be identified as the amount of plant growth (height of plant)

The Constants include all of the parts of the experiment that must be kept the same throughout all trials. Same type of seeds, container, amount of sunlight, water, etc.