The Great Apple Browning Race

What you need

• Water, 2 small cups
• Salt, 1 teaspoon
• Clear cups, 3
• Plate or tray, 1
• Paper, 4 small labels (optional)
• Crayons or markers (optional)
• Notebook (optional)
• Phone, for timer and photos (optional)
• Apple, 1
• Lemon juice, a little
• Knife, 1, for grown-ups
• Towel, 1 damp

How to do it

Grown-up prep: Wash the apple. A grown-up slices it in the first step, and the knife stays with the grown-up. Mix a spoonful of salt into a small cup of water. Pour a little lemon juice into a second cup and plain water into a third. Set a timer for 15-minute checks. Keep lemon juice away from eyes and any little cuts, and skip this one if anyone has a fruit allergy.

1. A grown-up cuts the apple into four round slices and lays them on the plate. A grown-up does this
2. Make four labels, for nothing, lemon, water and salt water. Put one next to each slice.
   Ask: Which slice do you predict will turn brown first? Which will stay fresh longest?
3. Leave the first slice alone. It is our 'nothing' slice.
4. Dip the second slice in lemon juice, coating both sides. Wash hands after.
5. Dip the third slice in plain water, then put it back on its spot.
6. Dip the fourth slice in the salt water, then put it back on its spot.
7. Check the slices every 15 minutes for an hour, and draw or photograph them.
8. After an hour, line up your pictures and rank slices from brownest to freshest.
   Ask: Was your prediction right? What surprised you?
9. Here is why: air turns the apple brown, and lemon juice slows it down.
10. Now show your friends, or race more foods! What will you test next?
    Ask: Which food would you like to race next?

Play it again

• Mystery dip: ask a friend to secretly pick a dip, then guess which slice is theirs by its color.
• Brand new racers: race a pear or banana slice and see if lemon still wins.
• Beat the clock: guess how many minutes each slice takes to turn brown, then check who guessed closest.