Today we become plant scientists! We will plant seeds and set up a real experiment. Scientists use a fair test to answer questions. In a fair test, you change only ONE thing. Everything else stays the same.
Here is an example. We want to know if plants need light. We plant two cups of seeds. Both cups get the same soil, the same seeds, and the same water. One cup goes in a sunny window. The other cup goes in a dark closet. Light is the only thing we changed!
The one thing we change is called the variable. If the dark plant grows weak, we learn that plants really do need light. We will watch our plants for many weeks and write down what we see.
1. In a fair test, how many things do you change?
2. What is the one thing you change called?
Adult help needed! Ask a grown-up to help with containers, soil, and seeds. Wash your hands after touching soil. Do not put seeds in your mouth.
Pick ONE variable to test. Circle your choice:
Light: one plant in a sunny spot, one plant in the dark
Water: one plant gets water, one plant gets none
My question: What will happen to the plant that does not get ____________________?
My prediction:
Read each test plan. Is it a fair test or not?
| Test Plan | Fair or Not Fair? |
|---|---|
| Two same plants; one gets light, one does not. Same water and soil. | |
| One big plant and one tiny seed; big plant gets more water. | |
| Two same plants; one gets water, one does not. Same light and soil. | |
| Two same plants; one gets no light AND no water. |
You need: 2 cups or small pots, potting soil, fast-growing seeds (beans work well), water, labels.
1. Fill both cups with the same amount of soil.
2. Push 2 seeds into each cup, about as deep as your fingernail.
3. Give both cups the same small drink of water today.
4. Label the cups: "Plant A" and "Plant B."
5. Put each cup in its test spot for your variable.
| Setup Question | Plant A | Plant B |
|---|---|---|
| Where is it placed? | ||
| Will it get light? | ||
| Will it get water? | ||
| How many seeds? |
Plant A's spot
Plant B's spot
A seed under the soil
Explain your experiment. What are you testing? What stays the same? What is different? Use full sentences.
Challenge: Design a tool or trick that would help you remember to check your plants every day. Draw it and label it!
How does it help you remember?
1. Why is it important to change only one thing in a fair test?
2. How many days do you think it will take to see a sprout?
3. What will you look for when you check your plants?