Hand Warmers - Do they work?
Samantha Au
Prince of Wales Secondary
Floor Location : J 171 D

Chemical hand warmers rely on a simple chemical equation between iron and oxygen, which generates iron oxide and heat. This heat helps keep our hands warm in the cold.

I compared the temperatures generated by 3 brands of disposable chemical hand warmers.
Thirty of each type of hand warmer were placed in 30 gloves (N=90) and the temperatures generated were measured with a thermometer inserted into the glove. Temperatures were measured every 15 minutes for the first four hours, and then every hour until the 6 hour mark.

A total of 1,709 data points were collected. Data analysis showed that Heat Factory peaked the earliest with the highest peak temperature, but this dropped significantly by 6 hours. In contrast, Little Hotties had the lowest peak temperature, but the highest sustained temperature at 6 hours. ANOVA analysis revealed that the average temperatures between groups at almost every time interval was statistically significantly different (p<0.05).

Differences in the activity of chemical hand warmers may be explained by differences in iron content, how porous the membrane is, or the overall mass of the warmer. Based on the data generated by this unique experiment, I would recommend Heat Factory for a short day of activity in very cold temperatures. Little Hotties would be more appropriate for long days at moderate-cold temperatures. Jobsite, which had peak and final temperatures between the other two brands, would be helpful for short days in the moderate cold.