Mummify an Apple
Big Idea:
Decay happens when bacteria and mold break down organic material, and both need moisture to survive. Egyptians used natron, a natural drying salt, to pull moisture out of a body so nothing was left for decay to work with. This experiment uses a baking soda and salt mixture to do the same thing to an apple.

Materials:

• One apple, cut in half
• Baking soda
• Salt
• A bowl to mix the baking soda and salt together
• Two small containers or bags to hold each apple half
• A spot where both halves can sit undisturbed for one to two weeks

What to Do:

Step 1: Make Predictions 
Before starting, ask your learner which apple half they think will hold up better after two weeks, the one buried in the mixture or the one left uncovered, and why. Record predictions on the lab sheet, this is important. The point is to test the prediction, not just watch.

Step 2: Mix the Natron Stand-In 
Combine equal parts baking soda and salt in the bowl.

Step 3: Bury One Half 
Cover one apple half completely in the mixture, the way embalmers packed a body in natron.

Step 4: Leave the Other Half Exposed 
Set the second apple half in its own container, uncovered, with no mixture.

Step 5: Check In Over Time Look at both halves every few days for one to two weeks. 
Record changes in color, texture, smell, and size on the lab sheet.

Step 6: Discuss

• Why did the buried apple half dry out and shrink instead of rotting?
• Why did the uncovered apple half turn brown, soft, or moldy?
• What do you think would happen if you used only salt? Only baking soda?

What's Really Happening (Caregiver Explanation):
Bacteria and mold need moisture to grow, and once they get it, they start breaking the apple down. The baking soda and salt mixture pulls water out of the apple through a process called osmosis, leaving nothing behind for bacteria and mold to use. That's why the buried half dries out and shrinks instead of decaying, while the uncovered half keeps its moisture and rots normally. This is the same basic principle Egyptian embalmers relied on. They packed a body in natron for about 40 days to pull out all its moisture before wrapping it in linen.

Digging Deeper:
This week's lesson also covered other cultures that preserved bodies in very different ways, bog mummies in Europe preserved by cold, low oxygen, acidic peat, and Lady Dai in China preserved in an airtight, charcoal packed coffin. Ask your learner: why might different environments call for different preservation methods? What do all three methods, Egyptian, bog, and Chinese, actually have in common? (Each one, in its own way, keeps moisture, air, or bacteria from reaching the body.)