Chemistry In My Life

Created by Alex Anderson

The Magic (or Chemistry) Behind Hand Warmers

1. What Specific chemical reactions are involved?

Well, in most of the hand warmers that we think of we think of the ones that we shake for a few seconds and then they will gradually get warm. So how that reaction happens is by the cellulose (acts as a filler), water, iron, carbon (that distributes the heat evenly), vermiculite, and salt (which acts as the catalyst) which when mixed together with air cause oxidation of the iron.

2. Where do we find the reactants?

Most of the reactants are household items. Like the water, iron, and salt. But the Cellulose is taken from the plant's cell wall. Carbon can be taken from coal or from other rocks that contain it. Vermiculite is found when other rocks are broken down and is obtained from that.

The picture below is a chunk of iron.

3. What happens to the products/byproducts?

The products go through a chemical change when exposed to air and the byproducts are where we get our heat from the hand warmers. These byproducts are said to be non-toxic. Because I am specifically talking about the air-activated hand warmers.

4. What are the environmental impacts?

The main cause for concern to the environment is the Vermiculite that is contained in the hand warmer mix. When Vermiculite is broken apart it is said to have amounts of Asbestos, but that was during the time where almost anything used for commercial purposes contained Asbestos. Another cause for concern is when the hand warmers are placed in an environment where the amount of oxygen may be greater than normal can cause the hand warmers to increase the amount of heat they throw off and the chance of burns to skin exposed to the hand warmers may be greater.

5. Are the reactions endo- or exothermic?

Oxidation of the iron in the pack causes an exothermic reaction. That is where the heat comes from when we use the hand warmers. Without this reaction the hand warmers may not be working so hot. (pun intended)

6. Who is affected by this chemistry?

The people affected by this chemistry are anyone that enjoys the outdoors, but also enjoy staying and toasty. Some examples of these people are fishermen, hunters, sporting event fans, workers that have to work outside during the winter months, and myself when its cold outside and I am at football practice.

7. How important is this Chemistry?

If you ask anyone that lives in the state of Minnesota most will say that "these things are a godsend when you are outside in the freezing cold winter." Another important reason for the chemistry behind hand warmers is if you are in any part of the world that has a cold season is that without these hand warmers some people wouldn't be able to do their jobs as effectly as they could be able to.

8. An interesting way to make your own hand warmers!

2 Tsp salt
2 ½ Tbsp Vermiculite (Can be purchased from
Hardware store or plant nursery)
2 Tbsp iron powder
(Can be purchased from science catalogue)
2 Tbsp fine activated charcoal
(The kind used in aquarium filters)
3 ½ Tbsp pencil sharpener shavings
2 Tbsp water
1 small disposable container
1 disposable spoon
1. Combine the dry ingredients in the small disposable
2. Add water and mix
3. The oxygen in the air will combine with the
ingredients to produce heat.

This information for the DIY hand warmers was from

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