Student Activity - Growing fungi on bread

Activity idea

In this activity, students grow fungi on bread to explore the features of fungi and what they need to grow. This simple investigation can be used to encourage students to design their own investigation.

Instructions

Fungi love to grow on bread. Fungal spores are all around us all the time, floating in the air. When they land on food, they can eventually grow into a fungus, causing the food to decay or go mouldy.

In this investigation, you will observe how fungi can grow on slices of bread. In a moist environment, fungi will generally grow within about a week (which is why we don’t generally eat food that has been lying around for a long time).

Warning: You shouldn’t breathe the large number of spores that the fungi produce, so you need to keep everything in a sealable plastic bag. Do not open the bag, even at the end of the investigation.

What you will need

• sealable plastic bags (zip lock or similar)
• slices of bread – one for every experimental condition you want to test
• paper towels

What to do

1. Think about an investigation. What would you like to test? For example:
   • How long does it takes until fungi first appear?
   • What area of bread is covered by fungi after 3 days, 5 days, 7 days?
   • Does white or brown bread make a difference?
   • Do fungi need light to grow? Do fungi grow better in sunlight or in darkness?
   • Does the temperature make a difference? Do the fungi grow quicker in cold, warm or hot conditions?
   • We recommend putting in a piece of damp paper towel, but you could investigate the effect of dampness. Do more fungi grow when the paper towel is dry, just moist or really wet?
   • Mushrooms are a type of fungi – do they make more fungi grow on bread? Add a mushroom to one of your bags – do you get more fungi? Do the fungi grow quicker? Do you get a different type of fungi?
   • Do fungi need oxygen to grow? If you have a bag sealer or vacuum pump, try taking all the air out of one bag and seeing how well the fungi develop.
2. Once you have an idea, plan how many bags of bread you will need and what conditions you are going to put them in. Remember to only test one condition with each bag, otherwise your results will be confusing.
3. Set up identical plastic bags and number them clearly with a marker pen or label. Place a paper towel in each bag – dry, damp or wet depending on your investigation. Add a piece of bread and seal tightly. Put each one in a different place and/or for a different amount of time to test your ideas about what fungi need to grow.
4. What do you think will happen in each of your bags? Write down your ideas.
5. As the investigation progresses, describe and draw or photograph the fungi that grow on your different slices of bread and keep notes about your findings. (This is what scientists do in the laboratory. They use a laboratory notebook to record their plans, ideas and findings.) You can then use your records to plan further investigations or to talk to others about what you found out.
   • Do you get more than one type of fungi growing on your bread?
   • Does the bread start to disappear? You could try weighing the bread every couple of days to see if the bags are becoming lighter with time.
   • What would happen if you left it there for weeks? (We don’t recommend this as it becomes a health hazard.)

Remember, the fungi spores that concentrate in the bags can be very dangerous. Do not open the bags at any time during the investigation. They can be disposed of in the rubbish at the end of the investigation, still sealed.