How to Make a Hand Warmer

Ever wondered how hand warmers work? Here is your chance to make your own hand warmer and experience the science (exothermic reactions) behind it all!

You will need an empty plastic container to mix the materials. If you're using the kit, empty the 1 lb of Iron100 Powder into a bag so that you can use the plastic container to mix and shake your mixture.

Using the measuring cup, take one full scoop (tablespoon) of the Iron100 Powder and add it into the empty container.

Take one full scoop (tablespoon) of Graphite Powder and add it into the container.

Close the lid and shake it for about 15 seconds.

Take one full scoop (tablespoon) of spacer/filler (Perlite, Vermiculite or Wood Dust) and add it to the container.

Using the smaller end of the measuring cup(teaspoon), fill it half way with salt and add it to the container. Close the lid and shake it again for another 15 seconds.

Use a spatula or spoon to mix it some more before pouring it into the bag. Fill the bag up 60% .

Using a transfer pipette, drop 2mL of water into the bag.

For added protection and durability, you may choose to place the bag into a cloth pouch to prevent the fine powders from smudging on your hands. You can also use a heat sealer (at low temperature) to close the bags.

Once the bag is sealed, lightly press on the powders and you will begin to feel it heating up!

After the bag cools down, you can add a little water to it and it will once again initiate the exothermic reaction!

If you want to use the hand warmer at a later time for a hiking trip or science project , simply place it in a zip lock bag making sure that no air gets in. Without air, there will be no exothermic oxidation and therefore no heat will be produced.

By using a glass alcohol thermometer, you can see how hot the hand warmer will get and how long it takes for it to start cooling off.