A Wonderleaf question
Why do apples turn brown after cutting?
a real page from the book
Apples turn brown after cutting because sliced cells let an enzyme meet air and apple chemicals that were separated before. The enzyme, polyphenol oxidase, helps start a reaction with oxygen, and that reaction makes brown compounds on the cut surface.
The apple has not suddenly spoiled; it is doing chemistry where you can see it. Lemon juice, cold air, or a snug cover can slow the change because they make the enzyme less busy or keep oxygen away from the fruit.
Wonder words
- enzyme
- oxygen
- reaction
- molecules
Try it out
Cut two apple slices, rub lemon on one, and compare their color after dinner.
Read the whole picture book
Watercolour scenes, straight answers, about three minutes cover to cover.
Open the picture bookKeep wondering
- How is chocolate made?
- How is cheese made?
- Why do fruits taste sweeter when they are ripe?
- Why do we cook food?
- Why does salt make food taste different?
- Why does toast turn brown?
One more wonder: Why is space so dark?
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