HOME >> News
Grade 7 Biology: Apple Investigation!

Recently our science teacher assigned us an experiment aimed at teaching us about how our skin defends us from invading bacteria.

We prepared three carefully cleaned apples and one rotten one. Then we treated each apple as follows:

·Clean apple 1: No treatment

·Clean apple 2: We inserted a toothpick into the rotting apple and withdrew it. Then we lightly drew the tip of the toothpick down the side of the second apple without breaking the skin.

·Rotten apple: We inserted a clean toothpick into the rotting apple and withdraw it;

·Clean apple 3: We followed the same procedure as the rotten apple but swabbed the scratches with a cotton swab dipped into rubbing alcohol. Then, we put all 4 apples into 4 separate bags. Then we observed for 4 days.

I learnt 2 main things from this experiment. Firstly, some things don’t always turn out the way people expect them to. Just like in this apple experiment.

Every student in our class thought that Clean Apple 3 would be perfectly fine because of the alcohol treatment. However the truth was during the last two days it rotted faster and more severely than any of the other apples, even though the Rotten Apple was initially the worst.

Secondly, I experienced utter joy accompanied with surprise and a feeling of a lightbulb being flicked on when I found the answer to the strange phenomenon I observed in the experiment. Of course, we also learnt about the correlation of alcohol, skin, and pathogens by carrying out the experiment. This experiment helped us a lot with our understanding of the immune system and our skin’s protection mechanism.

(Written by Eric 7(7)        Pictures by Ivan 7(2) )