Broccoli, like all plants, has chlorophyll, making it green. You can really “see” the chlorophyll when you boil broccoli. This is such a simple experiment that you can do this as you prepare dinner tonight with your kids. Make sure you have an extra head of broccoli for this experiment, unless you really like to eat overcooked broccoli.

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First, boil a pot of water. Add some cut up broccoli, and immediately observe the color. Allow the broccoli to cook for 15 minutes, and observe the color again.

What’s happening? When you first put the broccoli in the boiling water, the hot water allowed air bubbles to escape. This allowed you to clearly view chlorophyll, the chemical that makes broccoli green, so the broccoli should have appeared very bright.

After 15 minutes of cooking, chlorophyll undergoes a chemical change and the broccoli becomes a duller color. The heat makes it easy for the chlorophyll to lose magnesium. The magnesium is replaced by hydrogen from natural acids in the plant. This chemical change causes the color to change.

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Comments

2 Responses to “The Science of Broccoli”

  1. Aurora Lipper says:

    Good question! I updated the explanation above. The color change is caused by natural acids in the broccoli.

  2. hannah_athauda says:

    Hi Aurora, why does acid enter the broccoli and from where?