Understanding Controlled Experiments

Mark and Molly conduct an experiment to determine the optimal watering schedule for plants. Mark waters his plant once a week with sunlight, while Molly waters hers three times a week without sunlight. Mark's plant thrives, leading him to conclude that less frequent watering is better. However, the experiment is flawed due to unequal sunlight exposure. A controlled experiment is needed, where all conditions except one variable are kept constant. When sunlight is equalized, Molly's watering schedule proves more effective. Repeating the experiment ensures accuracy, highlighting the importance of controlled experiments in science.

What was the initial watering strategy used by Mark for his plant?

• 150 mL of water every other day

• 50 mL of water every day

• 200 mL of water twice a week

• 100 mL of water once a week

Where did Molly place her plant, and how often did she water it?

• In the garden, 200 mL twice a week

• In the closet, 100 mL three times a week

• In the window, 100 mL once a week

• In the kitchen, 50 mL every day

What was the main reason for the unfair comparison between Mark's and Molly's plants?

• Different temperatures

• Different pot sizes

• Different amounts of sunlight

• Different types of soil

What did Mark and Molly fail to control in their initial experiment?

• Amount of water

• Type of plant

• Amount of sunlight

• Type of soil

In a controlled experiment, what should remain constant?

• All variables

• All variables except one

• None of the variables

• Only the independent variable

What should be the only difference between the two plants in a controlled experiment?

• The type of soil

• The size of the pot

• The amount of water

• The type of plant

What is the independent variable in Mark and Molly's experiment?

• Type of plant

• Type of soil

• Size of the pot

• Amount of water

What was the outcome when both plants received equal sunlight?

• Both plants died

• Both plants were unhealthy

• Molly's plant was healthier

• Mark's plant was healthier

Why is it important to repeat experiments?

• To confuse the results

• To ensure accuracy and avoid mistakes

• To make the experiment longer

• To use more resources

What is a common use of controlled experiments in science?

• To keep all variables constant

• To test multiple variables at once

• To isolate the effect of one variable

• To change all conditions frequently