Canadian schoolgirl creates Hollow Flashlight powered by body heat


June 30, 2013

Canadian high school student Ann Makosinski demonstrating her body-heat powered Hollow Flashlight

Canadian high school student Ann Makosinski demonstrating her body-heat powered Hollow Flashlight

At the tender age of 15, Canadian high school student Ann Makosinski has designed and built a flashlight powered by body heat. Her Hollow Flashlight secured her a finalist slot in the 15-16 age group of the Google Science Fair ahead of thousands of entries from more than 100 countries. My science project in tenth grade was a volcano that only worked about half the time, so I think she has me beat.

The LED flashlight relies on the thermoelectric effect, with tiles that generate electricity from the differences in temperature to generate electricity. The tiles are fixed to the outside of a hollow tube so that when held, one side of the tile is heated by the warmth of the hand, while air flowing through the hollow tube helps keep the other side cool. The electricity generated by the temperature differential between either side of the tile powers the LED light.

Makosinski built two different flashlights. The first was made using a tube of aluminum, which is a good heat sink material thanks to its high thermal conductivity, while the second was built using a PVC tube.

Both models work better when the difference between the ambient temperature and body temperature is greater, which is to say, when it's colder. So while the flashlights worked with an air temperature of 10° C (50° F), they emitted more light with the air temperature at 5° C (41° F). Still, she claims that both were able to maintain a steady beam of light for 20 minutes, even in the warmer temperature.

The final cost of each flashlight came to only just over CA$26 (US$25), but if mass-produced, the cost would obviously be substantially lower.

Makosinski and the 14 other Google Science Fair finalists will travel to Google's Mountain View, California campus in September where winners will be announced in each of the three age groups. One grand prize winner will also receive a $50,000 scholarship from Google and a trip to the Galapagos Islands.

Makosinski explains her design and demonstrates her Hollow Flashlight in the following video.

Source: Google Science Fair via

About the Author
Dave LeClair Dave is an avid follower of all things mobile, gaming, and any kind of new technology he can get his hands on. Ever since he first played an NES as a child, he's been an absolute tech and gaming junkie. All articles by Dave LeClair

"Google" Science fair? Were the admission tickets tax free then?


Ann, A vary simple but original thought on your part for a device that will likely be commonplace in a decade. I implore you to hold on to royalty rights. Money does not buy happiness but it allows you freedom to pursue happiness where you wish to look for it.


That's an intelligent cutie, stay in Canada if you want your green tech flash light to make it to production.


Amazing..Looking forward to buying one..Why didn't I think of that

Roger Aikins

This concept is really brilliant. And - wow! - what a gifted kid; if her science career flops (unlikely) there's always public relations, acting or modeling.

Fritz Menzel

Thermoelectric modules have been around for many years. They will produce current when hot and cold are applied, but as a reliable source of electricity - it falls short. I will give her an A for cleverness!


That is just so cool.


Yup, if not a scientist or engineer, she can have a "modeling" career. The machining of the aluminum, its flat spot, the perfect fit between the bezel and inner/outer tubes, the perfect clearances, all worked in concert to create a model that would be expected from a Catholic School student without a machine shop as would be found in a vocational school.

Part of being a good scientist is disclosure of assistance and providing references for your sources. I just refuse to believe others did not contribute significantly to the modeling and she merely had an idea. I'd also note that the Chinese are scrambling to understand this, as I write this, on lighting forums, so it'll likely be on the shelves by xmas.


If there is one thing I know about females, it is that they are rarely good sources of heat. "I'm cold!" "Put a blankie on me!" "You obviously aren't using your jacket, can I have it?" As warm as the room is claimed to be, I'd almost believe that her hand was the cold side of the thermoelectric junction.

In any case, this could be a pretty neat product for late-night wilderness rescue teams but even the warmest of hands probably won't make it work in warmer climates. If she has an opportunity to take it to market, I imagine it might sell to survivalists living in Alaska, Canada, Scandinavia, and Russia...probably nowhere else, especially if Chinese companies are developing similar, if shoddy, products that will almost certainly sell for less.

Justin Chamberlin

Add a capacitor so you can save up some charge so you have both the stored power and generated power to get a brighter light.

Michael Crumpton

In hot climates a small instant cold pack could be inserted into the cylinder to provide the thermal differential. The cold pack is far more likely to be useful when you need the flashlight than batteries.


Justin, howsabout we skip the discussion of your love life and stick with discussing the flashlight? ;

Kevin Frothngham

It occurred to me later that using a rechargeable non-combustion heat pack (say caustic soda and water) could be used to heat the outside and be more cost effective than the cold packs.


Not hard to work out from the patronising sexist drivel here that this website is for blokes not chicks. Slowburn sees a winner. this is very rare.


re; solutions4circuits

So you are saying girls can not work with their hands? I disagree; I was taught to stick weld by a woman.

re; nutcase

Good ideas are. I currently use solar yard lights as flashlights but they tend to have dead batteries cold winter mornings.


Ann, you have done good & creative idea to generate power. This will be help next generation to be more eco friendly.

Piyush Kanani
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