Independent and Dependent Variables

“A scientist wants to test if different amounts of fertilizer affect how tall tomato plants grow. They give one group of plants 5 grams of fertilizer per week, another group 10 grams, and a third group 15 grams. After six weeks, they measure the height of the plants. What is the independent variable and what is the dependent variable in this experiment? A student is investigating whether the color of light affects the rate of photosynthesis in algae. They shine red light on one group of algae, blue light on another group, and green light on a third group. They then measure the amount of oxygen produced by each group of algae. What is the independent variable and what is the dependent variable in this experiment? Researchers are studying if the amount of sleep a person gets affects their reaction time. They have one group of participants sleep for 6 hours, another group for 8 hours, and a third group for 10 hours. The next day, they measure how quickly each participant responds to a visual stimulus. What is the independent variable and what is the dependent variable in this experiment?”