The Occurrence of Water in Living Things

1. All living organisms consist mostly of water.
2. The adult human body is about 60% water, by weight, and 75% by volume.
3. As much as 95% of the weight of some plants is due to the water they contain.

Experimental Question: Which organic material has the greatest percentage of water: grass, grapes, or carrot?

State Your Hypothesis: ___________________________________________________________

Collecting Data

1. Weigh a handful of grass clippings then set them on a newspaper to dry overnight. Record data for before and after weights

2. Measure the weight of a few grapes, then cut them in half and place on newspaper to dry. Record the weight both before and after drying.

3. Measure the weight of a carrot then cut into strips and set out to dry. Record data.

Materials Needed

Data Table

Fresh (g) Dried (g) Total water lost (g) Percent Water
grass
grapes
carrot

Analysis

1. Why was it necessary to cut the items into strips?

 

2. Which material contained the most water (percentage)?

 

3. 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.

 

4. 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.