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Mould Growth Investigation Worksheet

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Mould Growth Investigation Worksheet

At a dinosaur dig, Oliver, Mei and Matilda find that damp food left in a warm field tent has changed. They plan a fair investigation into how moisture affects mould growth on bread. Read the evidence and answer each question. Do not open or handle mouldy samples; an adult should seal and dispose of them.

Plan a fair test

The team compares two bread samples. Both are the same size and type, kept in identical sealed clear bags in the same dark cupboard for seven days. Sample A is dry. Sample B has a measured teaspoon of water added before sealing. They do not open the bags.

1.What is mould? Choose the best description.

A kind of fungus made of tiny living organisms
A type of dirt that cannot grow
A plant that makes its own food using sunlight

2.What is the independent variable in the team's test?

3.Name two things the team keeps the same so the comparison is fair.

4.Write a prediction: which sample do you expect to develop more mould, and why?

Record and interpret evidence

After seven days, the bags are examined from the outside. The team estimates the percentage of each bread surface covered by visible mould.

Sample A — dry bread Mould-covered surface: 5%

Sample B — bread with added water Mould-covered surface: 35%

5.Which sample had more visible mould, and how much greater was its mould coverage?

6.Which conclusion is best supported by these results?

Adding moisture was associated with more mould in this test.
Light caused the mould because one sample was kept in sunlight.
Dry bread always grows more mould than damp bread.

7.The team says, “Water definitely caused all the difference.” Why is this claim stronger than the evidence allows?

8.Suggest one improvement that would make the investigation more reliable.

Safety and next steps

Mould can release tiny spores into the air. Keep samples sealed and ask an adult to manage disposal.

9.Explain why the team should not open the sample bags to smell or touch the bread.

10.Plan a follow-up test to investigate a different factor affecting mould growth. State the factor you would change and one condition you would keep the same.