Heated Slippers
Cayleigh Abel and Sara Pesic
Remuera Intermediate School
Year 8 Electronics and Soft Materials, 10-week project
Teacher: Selena Hinchco
Year 8 students Cayleigh and Sara decided to tackle an old problem: cold slippers. Some sort of heating system was the answer, and one that posed an interesting technical challenge for the students.
After investigating snap heat pads and microwaveable wheat bags (which they found cooled too quickly), they decided to insert a heating element made from nichrome wire into the slippers.
Unfamiliar with working with nichrome wire, they asked an expert, Ross Peterson from Bright Sparks, to come and show them how to go about it. The girls ran a six-volt current from a rechargeable sealed lead-acid battery through different lengths of heating wire to find the best length to use. They then inserted the wire, covered in tinfoil and stuffing to keep the circuit safe, into each slipper.
Cayleigh and Sara designed a case for the batteries; this had a master switch and crocodile clips which allows a user to charge each slipper separately. After 30 minutes of charging, the slippers reach 39°C and stay at that temperature for about 15 minutes.
Aesthetics, ergonomics, and of course safety, were important considerations in the project. Cayleigh and Sara chose "good looking" slippers in unisex colours, and ensured the underfoot heating wires were unobtrusive, fully insulated and completely waterproof. The whole setup – slippers and charger were small enough to be easily portable.
The project won the girls third place in technology at the NIWA Auckland City Science and Technology Fair and fourth in the 2007 National Bright Sparks Hi Tech Competition.
Teacher comment
From identifying their problem and defining their brief, through to discussing their work with industry technologists at the Bright Sparks Expo, Sara and Cayleigh showed exceptional commitment and determination. They regularly evaluated their technological outcome against the specifications they wrote and ensured that modifications they made were related to those specifications. They kept accurate and relevant records, observations, and research in a stunning logbook that has become an exemplar for other students in our school.
Related links: Bright Sparks website
