Why is important to make a hypothesis at the start of an experiment? Walk in Get 5 points! Take out folder, notebook, pencil box. Put away backpack. Copy the question at the back and answer in sentences: Why is important to make a hypothesis at the start of an experiment?

answer Scientists begin by making a hypothesis so they have made a prediction. This helps them choose their variables and controls so they can test the hypothesis.

Scientific method review

For each experiment coming up… Think of the hypothesis being tested, the variables and the controls. Think of what a follow-up experiment could be. Be ready to share your ideas if you are called on!

Experiment 1 Some students want to find out if playing music to a plant will help it grow better. They play classical music for 4 days, then rock music for 4 days, then children’s songs for 4 days, and no music for 4 days. After each 4 day period, they measure how wide the leaves are.

Independent variable (what will they change)? Dependent variable (what will they measure)? What could they control (keep the same) so it is a fair experiment? What follow-up experiment could they do to continue investigating? Which one is better? Play other kinds of music to plants. Try adding fertilizer to the plant’s soil.

Experiment 2 Some students want to see if people sleep better after listening to different kinds of music. They have people listen to rock music, classical music, folk music and jazz music before going to sleep. They record how many hours the person slept.

Independent variable (what will they change)? Dependent variable (what will they measure)? What could they control (keep the same) so it is a fair experiment? What follow-up experiment could they do to continue investigating? Which one is better? Try other kinds of music to see if people sleep longer. Try giving people a bedtime snack.

Experiment 3 Some students want to try an egg-drop experiment, dropping an egg from 30 feet with some protection around it. They make 4 protective shells, out of Styrofoam, cotton balls, cardboard and plastic. They check each one to see if the egg survived without breaking.

Independent variable (what will they change)? Dependent variable (what will they measure)? What could they control (keep the same) so it is a fair experiment? What follow-up experiment could they do to continue investigating? Try other kinds of materials around the egg. Find out people’s favorite ways of eating eggs.

Experiment 3 Some students investigate if plants grow differently if they are “watered” by something other than water. They try watering them with either milk, coke, juice or water. Each day they count the number of leaves on the plant to see if it grew more.

Independent variable (what will they change)? Dependent variable (what will they measure)? What could they control (keep the same) so it is a fair experiment? What follow-up experiment could they do to continue investigating? Try other kinds of liquids to water plants with. Limit the amount of sunlight the plants get.