Micro Organisms Experiment

Some people have been saying Class AS has been a bit smelly recently. No, it isn’t the children’s feet or Mr Stanley forgetting to put on his deodorant in the morning, but an interesting experiment we have been running on micro organisms.


About two weeks ago, we placed three slices of cheese on three slices of white bread and wrapped them in clingfilm. Weplaced one on the radiator by the window sill in the classroom (heat and light), one in Mr Stanley’s cupboard (heat and dark) and one in a fridge in the staffroom (cold and dark). We left our slices for two weeks and then looked at them today.

The slice of bread and cheese that had been left in the fridge was almost unchanged. The bread was moist in the centre, but had hardened around the outside. Otherwise it was unchanged.

The slice of bread and cheese that had been left in the Mr Stanley’s cupboard had changed dramatically. Green mould was beginning to form all around the cheese where moist bread had stuck to it, while the bread itself was also turning green.

The slice of bread and cheese that had been left by the window sill had changed the most dramatically. The cheese had sweated and was now bone dry although mould hadn’t formed on it. However the bread had turned many different colours including black orange as the photos below show.

The children concluded that heat increases the rate of production by micro organisms and that cold slows this down. However, they were not completely satisfied that they had adequately found the differences in how micro organisms respond to dark and light. We will revisit this in the future.


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