When I was a young child (time frame here is the late 80s), I recall owning a pair of gloves called “Freezy Freakies”. Portions of these gloves, when exposed to temperatures below a certain point, would change color, creating a picture of something.
A) Are these gloves still around?
B) What is the chemical reason behind this color change?
Thanks.
Between my sisters and myself, we had a pair of Frezzy Freakies with “I Love Snow” written on them, one with lizard-like scales, one with penguins I believe… Oh I can’t remember any others right now.
Don’t know how they work, but thanks for bringing back this great memory!
My WAG is that they work in a similar way to the coffee mugs that change color with heat. Or the Hypercolor T-shirts.
Yep, I had a pair of freezy freakies too!
They were pretty cool, but I dunno how they work.
Good God, I actually remember the damn commercial for those things. How scary is that?
I don’t know exactly how they work, either, but I strongly suspect it’s along the same lines as a Ken doll that belongs to the Tzeroling’s friend. The legs turn a dark purple in warm water (to simulate a skin-diving suit) and fade in cold water back to a normal plastic flesh tone.
WAG
A chemical that forms bonds when given sufficient heat energy and thus changes its light-reflecting properties?
No, what’s scary is that I’m having an adult conversation with people whose childhood memories are from the 80’s. Simple arithmetic says it’s possible, but still …
Anyway, there are, of course, a lot of products that change color with temperature: mood rings, those mugs that get a picture on them when you pour something hot in them, etc.
Materials that change color with temperature are called “thermochromic”.
There are two basic technologies - liquid crystals and leuco dyes. “How stuff works” has some good background on this, but doesn’t actually say how they chemically work:
I didn’t know builtin battery testers were thermally activated - makes sense, though.
Leucodyes actually apparently go colorless when they heat up - the various color effects in commercial products are probably achieved with suspensions of other pigments which come into play when the leucodyes go transparent.
This link has a demonstration that a builtin battery tester is actually a thermochromic device, and mentions a specific thermochromic substance, copper mercury iodide: