Doppler 9&10 STEM – My Apple is Brown!

Like last week, we are talking about Oxidation.

In case you forgot the formula here it is for Copper… Cu + O2 -> 2CuO

Okay, as scientists and meteorologists we LOVE formula’s okay. Apple

I am certain you and the kids have eaten apples and seen them turn brown VERY quickly. That happens because the molecules in your apple are oxidizing or obtaining MORE Oxygen. When the apple is cut the plant tissue (the part we eat) is exposed to oxygen. The exposure to oxygen causes an enzyme known as Polyphenol oxidase (PPO) to oxidize polyphenols. What does this mean in laymen’s terms? The acidic apple tissue reacts with oxygen and browns.

Here is what you need at home!

You Will Need:


Lemon Juice






Other Experimental Liquids


  1. Cut up 1 apple into several slices
  2. Fill up a bowl halfway with lemon juice
  3. Pour 1 tablespoon of salt into your cup
  4. Stir the salt into the lemon juice for 30 seconds or until salt dissolves
  5. Fill up a bowl halfway with water, add salt
  6. Fill up a bowl halfway with water, add sugar
  7. Dip the apple into your different liquids
  8. Place the apple on a plate and compare with untouched apple
  9. Repeat with other liquids such as juice

If your kiddos try this experiment, send us photos of you and your experiment and you might get to see it during weather on The Four on Tuesdays and Thursdays!

Make sure you tune in every Tuesday for a New 9&10 STEM. Send us an email at weather@9& or find us on Facebook and at Doppler 9&10 Weather Team if you have a weather question or want something in science explained! It does not have to be weather-related! Anything Science or math-based we’ve got you! You can always get the latest forecast on as well as interact with us on social media!

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Categories: Doppler 9&10 STEM, the four