Effect of Freezing During Transport

Procedure

1. Obtain two pieces of produce (use potatoes, carrots, apples, bananas - whatever you want but they should be the same). These will be called your "specimens."

2. Cut one specimen in half. Call this specimen “frozen” and label the two halves “FA” and “FB.” Place the two halves in a beaker in the freezer overnight.

3. Cut the second specimen in half, call it “unfrozen” and label the two halves “UA” and “UB.” Place them in a beaker.

4. The next day, place FA and UA in separate beakers. Put them in a cupboard.

5. Retrieve FB and compare it to UB. Record any observations.

6. When the frozen specimen section (FB) has thawed (this might be the next day), squeeze both specimens (FB and UB). Record any observations. After making your observations, you can discard both FB and UB.

a) Did water come out of both specimens? If not, which one?

b) Where does the water come from?

c) What effect does freezing have on the plant cells?

7. Observe the sections that you placed in the cupboard (FA and UA) every day until decay has begun in both specimens. Record the daily observations. It will be useful to use the binocular microscopes for this purpose.

d) Which specimen began to decay sooner?

e) What was the first sign of decay? Other signs?

f) Why did one specimen decay faster than the other?

g) What causes the decay?

h) Why is it important to protect frozen food in the home from thawing?

i) What contributes to the smell of decay often noticed in early spring?

j) What is the relevance of this activity to what we’ve learned about the distribution of food?