Make a Homemade Hand Warmer!

Here's a perfect experiment for a cold, wintry day! The promise of warmth and coziness is fantastic motivation for your child to experiment with this practical application of chemistry—keeping his hands warm. The loaded combination of a few natural materials results in a natural warming device that will astonish your child! This homemade hand warmer will work its magic for up to six hours, although the iron will continue to rust for an entire day. The best part: it's biodegradable and non-toxic.

What You Need:

• Pencil
• Pencil sharpener
• Bowl
• Self-sealing sandwich bag
• 1 tsp. salt
• 2 tbsp. water
• 2 tbsp. vermiculite (garden store)
• 2 tbsp. iron powder (hobby shop)
• 2 tbsp. pulverized activated charcoal (pet store)*

*If you can’t find pulverized charcoal, put coarse charcoal in a bag and mash it with a hammer.

What You Do:

1. Have your child repeatedly sharpen a pencil and crush the shavings, until there are about 3 tablespoons of pencil shavings.
2. Invite him to mix all of the ingredients together in a bowl, and then pour all of the ingredients into a sandwich bag.
3. Make sure that your child allows air gets into the bag before sealing it up.
4. Encourage him to observe the results. What happens? How quickly did the homemade hand warmer begin to heat up?

What's Happening?

Where does this mysterious heat come from? A long-lasting chemical reaction occurs when oxygen (air) mingles with iron. This is called an exothermic reaction, because it produces heat.

All of the ingredients in this "trick" play a role! Iron is the energy source. The chemical reaction is accelerated by the salt and the charcoal. Water serves as the combining medium, which is evenly diffused by the vermiculite. Lastly, sawdust insulates the hand warmer so that it retains heat.