I want to make a glow in the dark substance that glows only if it gets warm.
How do I obtain this substance, or what chemicals to I need to mix to make it?
It's going to go in a sealed glass jar with some magnetic materials, and I'll use a magnet to move around the magnetic part (iron filings?) to heat up the substance and make it glow.
Ideally, the substance should only glow if it goes above 110 degrees Fahrenheit. It can't be a gas, because it's going in a sealed glass jar. It also can't produce toxic fumes, but it can be toxic. Also, I don't want the magnets to be the only things to make the substance glow. I want to put it next to an oven, in the bathroom while I take a hot shower, next to the heater, or near a light-bulb as a temporary light source for when the power goes out.
I don't care if it's a solid or a liquid, or uses a state change to achieve the glow effect. However, it absolutely CANNOT be a gas, because if the glass breaks, I don't want to have all of the fire alarms going off at the same time while everyone has passed out from lack of oxygen.
An idea for a use for this:
because it's going to be warm when it's glowing, It could act as a good solid-state heater, and you could reheat it when the glow starts to fade. Kids will love it on a cold winter's night, because it's a night light that helps to warm their cold room (or their feet).
A half joke:
Now I need to make it glow yellow when it's warm and turn cold gray when it's cold, and then I can say that I'm an accomplished alchemist, and that I can turn lead into gold!
On a serious note,
I have a budget of around $100 to make this work, but the cheapest way of doing this would be best.
However, any way of doing this will work because it will be helpful to lots of people even if I can't afford it.