1. Question
Does Miracle Grow help tomato plants grow larger diameter tomatoes?

2. Hypothesis
If I use Miracle Grow then it will make my tomatoes larger in diameter because it fertilizes the tomato plant better than soil.

3. List of Materials 6 pots 1 kg soil 1kg Miracle Grow Water Sunlight
6 tomato plants…

4. Procedure 1. Put equal parts of soil in 3 of the pots.
2. Put equals parts of Miracle Grow in the other 3 pots.
Etc…

5. Manipulated Variable
I changed the Soil to Miracle Grow.

6. Responding Variable
What I am looking to change in response to changing the soil is the diameter of tomatoes.

7. Constants and Controls
Same amount of water
Same amount of sunlight
Same temperature
Same location
Same size pots
Same amount of soil or Miracle Grow…

8. Tomato sizes (cm round)
Data Table
Tomato plant
Miracle Grow or soil
Tomato sizes (cm round) 1 MG
10, 12, 12 2
9, 10, 12 3
8, 11, 12 4
Soil
7, 7, 8 5
6, 8, 8 6
7, 8, 9

9. Conclusion
A) My results clearly show that Miracle Grow helped me grow larger tomatoes. The average size tomato with Miracle Grow was 11 cm while the average size tomato with regular soil was 7 cm (see data table for all tomato sizes).

10. Conclusion Continued
B) My hypothesis was therefore correct because the tomato sizes were larger when Miracle Grow was used than when it wasn’t.

11. Conclusion Continued
C) A possible source of error in this experiment would be that the first tomato plant might have gotten too much Miracle Grow. Next time I will use a triple beam balance to mass the same amount of soil or Miracle Grow for each pot.