Transcript:

Let's look at the toaster that's sitting on your countertop. You put a slice of bread, and you engage the toaster; the filament becomes red hot. Red, though, is not the dominant wavelength that the toaster filament is emitting.

No, the dominant wavelength that the toaster filament is emitting is in the infrared. You can't even see it. That is the dominant energy or the wavelength that that filament is emitting, and it is the infrared that is browning your toast. The infrared heats up only surfaces. It doesn't heat up the bulk of the medium, which is why the toast is brown only on the outer surfaces.

This is one thing. The second is to realize that red on the visible spectrum is the coolest temperature. It is not the hottest. Violet, indigo, blue, green, yellow, orange, red — that's the visible spectrum. Red is the coolest temperature. Violet is the hottest temperature on the visible spectrum.