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It’s almost Mother’s Day, mummy!

By Jasmine, 11 May 2013

Looking for a mummy this Mother’s Day? Try this activity!

Written by Beth Askham

You will need

• Apple
  

  Peel your apple, ready for desiccation.

• Table salt
• Bicarb soda
• Vegetable peeler
• Teaspoon
• Plastic container or bowl that fits an apple
• Non-toxic PVA glue (optional)

What to do

1. Peel the apple with an adult’s help.
   

   Carve out a face in your apple head. Does it look like your mummy?

2. Using the teaspoon, carve out the features of your mummy’s head in the apple. (You could make it resemble your mum for Mother’s Day!)
3. Mix 1 part bicarb soda to 5 parts salt so you have enough to completely bury your carved apple. Now totally immerse your apple head in salt and bicarb! This is easiest if you pour some of the salt and bicarb mix into the container, place your head on top and then pour in the rest around the head.
4. Leave your head alone in the mixture for several weeks.
5. You can then remove the apple head from its salty tomb. You should have a wonderfully dry, wrinkled apple mummy skull. If it smells bad or looks rotten, throw it away.
   

   The salt around the apple is an example of a desiccant – it absorbs the moisture in its surroundings, in this case the apple.

6. If you are feeling macabre you can decorate it with button eyes and some human hair clippings.
7. You can also coat your mummy head with PVA glue which will help it last for a long time.

What’s happening?

The salt around the apple is an example of a desiccant – it absorbs the moisture in its surroundings, in this case the apple.

Bacteria and mould thrive in moist environments, and drying out the apple prevents bacteria from causing the apple to rot.

Adding a coat of glue helps prevent any moisture from getting inside the apple, and you can keep your shrunken head for archeologists to find in the future.

Real-life science

A decorated desiccated mummy head.

Salt was one of the ingredients that ancient Egyptians used to make mummies. To mummify a body, Egyptians would remove the brain and all the internal organs after a person had died.

A mixture of natural salts called natron was then stuffed inside and around the body. Natron salts were native to the area, and not unlike today’s bicarb soda.

After days of drying with the desiccant natron, the body was wrapped up with linen soaked in resin. The resin hardened and acted in the same way as the glue by stopping moisture getting inside.

Other easily available desiccants are silica gel packets (the ones labelled ‘do not eat’) and uncooked rice. Why not try the shrunken head experiment using other desiccants to see which is the most effective?

If you’re after more science activities for kids, subscribe to Double Helix magazine!