Decomposing BananasMrs. Turner’s 4th Grade Class

Ask A Question

What causes food to spoil?

Does dry yeast make food spoil faster?

Write A Hypothesis

We think that the banana slice WITHOUT the dry yeast will spoil faster than the banana slice WITH dry yeast because we think that the dry yeast will protect the banana from the air.

Make A Prediction

If the banana slice has no yeast on it, then it will spoil faster because of the air exposure.

If the banana slice has yeast on it, then it will spoil slower than without because the yeast is protecting the banana from air.

Perform Experiments

1) Put a banana slice in each bag. Label one bag P for Plain.

2) Sprinkle 2/3 spoonful of dry yeast on the other banana slice. Yeast is a Decomposer so label this bag D.

3) Seal both bags. Put the bags in the same place.

4) Check both bags every day for a week. Observe and record the changes you see in each bag.

Perform ExperimentsBag Day 1 Day 2 Day 3 Day 4 Day 5

P 3.5 cmWhite/yellow

colorSmells like a

banana

D 3.5 cmCovered in dry yeast – brown

Smells like Cheerios

Day 1 - Plain Day 1 - Decomposer

Perform ExperimentsBag Day 1 Day 2 Day 3 Day 4 Day 5

P 3.5 cmWhite/yellow

colorSmells like a

banana

3 cmWhite/brown/yellow colorSmells like

rotten banana

D 3.5 cmCovered in dry yeast – brown

Smells like Cheerios

3 cmCovered in dry yeast – whiteSmelled like

rotten grapes

Day 2 - Plain Day 2 - Decomposer

Perform ExperimentsBag Day 1 Day 2 Day 3 Day 4 Day 5

P 3.5 cmWhite/yellow

colorSmells like a

banana

3.5 cmWhite/brown/yellow colorSmells like

rotten banana

3.5 cmBrown/black/

off-white colorSmells like an

old banana

D 3.5 cmCovered in dry yeast – brown

Smells like Cheerios

3.5 cmCovered in dry yeast – whiteSmelled like

rotten grapes

3.5 cmCovered in dry yeast – brown

Smells like Cheerios and

old milk

Day 3 - PlainDay 3 - Decomposer

Perform ExperimentsBag Day 1 Day 2 Day 3 Day 4 Day 5

P 3.5 cmWhite/yellow

colorSmells like a

banana

3.5 cmWhite/brown/yellow colorSmells like

rotten banana

3.5 cmBrown/black/

off-white colorSmells like an

old banana

3.5 cmBrown/black/off-

white colorSmells like an

old banana

D 3.5 cmCovered in dry yeast – brown

Smells like Cheerios

3.5 cmCovered in dry yeast – whiteSmelled like

rotten grapes

3.5 cmCovered in dry yeast – brown

Smells like Cheerios and

old milk

3.5 cmCovered in dry

yeast – tanMushy

Smells like fresh bread

Day 4 - PlainDay 4 - Decomposer

Perform Experiments

Bag Day 1 Day 2 Day 3 Day 4 Day 5

P 3.5 cmWhite/yellow color

Smells like a banana

3.5 cmWhite/brown/yellow color

Smells like rotten banana

3.5 cmBrown/black/

off-white colorSmells like an old

banana

3.5 cmBrown/black/off-

white colorSmells like an old

banana

3.5 cmBrown/black/off-

white colorSmells like an old

banana

D 3.5 cmCovered in dry yeast – brown

Smells like Cheerios

3.5 cmCovered in dry yeast – whiteSmelled like

rotten grapes

3.5 cmCovered in dry yeast – brown

Smells like Cheerios and old

milk

3.5 cmCovered in dry

yeast – tanMushy

Smells like fresh bread

3.5 cmCovered in dry

yeast – tanMushy

Smells like fresh bread

Banana is disappearing

Day 5 - Plain Day 5 - Decomposer

State Your Conclusion

o It turns out that our hypothesis was incorrect. The banana slice with the yeast spoiled faster. The yeast ate the banana slice. Yeast is a decomposer which means that it eats the remains of producers/consumers. A banana is a producer.