Investigation: How Much Water Is In a Plant?
Premises:
1. All living organisms consist mostly of water.
2. The adult human body is about 60% water.
3. As much as 95% of the weight of some plants is due to the amount of water they contain.
Experimental Question: Which organic material has the greatest percentage of water: grass, grapes, or carrot?
State Your Hypothesis:
Materials Needed
- balance or digital scale
- grass clippings or leaves, grapes, carrot
- newspaper for drying plants
Collecting Data
1. Weigh a handful of grass clippings then set them on a newspaper.
2. Weigh four grapes, then cut them in half and place on newspaper to dry.
3. Weigh a single carrot then cut into strips and set out to dry.
4. Weigh all the materials after they have dried overnight.
Data Table & Analysis
| Fresh (g) | Dried (g) | Water Lost (g) | Percent Water | |
| grass | ||||
| grapes | ||||
| carrot |
1. Which material contained the most water (percentage)? How do you know?
2. Grass is a leaf, grapes are fruits, and a carrot is a root. Based on the data of this lab, do different parts of the plant contain more water than others? Suggest a reason for this.
3. A bag of popcorn kernels weighs 22 grams, and after popping them, the popcorn is weighed. The weight of the popcorn is 16 grams. Explain why the popcorn weighs less than the popcorn kernels.
4. Do your results confirm any of the 3 initial premises in this investigation? Explain reasons why your results may be different.
Related Resources
Properties of Water – Investigation exploring cohesion, adhesion, heat capacity, presented as lab station activities
Graphing Practice – given data sets, such as video games scores and shirt colors, students create line and bar graphs, activity paired with growing sponge animals while students wait on results
Is Microwaved Water Harmful to Plants – use germinating seeds that have been soaked in distilled water and microwaved water
How Do Hormones Affect Plant Growth – use gibberellic acid to show how plants respond to growth hormones