Of course that being said I’d expect him to feel the heat since last I checked there used to be a huge solar energy plant in the American south west that used alot of mirrors to collect energy and shine it on a tower.
When my daughter was curious about how a TV remote worked, I told her about infrared. Then how infrared was a form of light that humans can’t see. She was about 8 or 10 at the time, and she’d also been curious about mirrors…so she pointed the remote at a mirror which reflected the image of the TV. Yep, the remote worked when its signal was bounced by the mirror. It wouldn’t work when it was pointed that way, but not at a mirror.
Flat mirror, because that’s what average people have in their purses (at least I think). Alternativly a watch face, such as kids use to make circles onto the blackbord on a sunny day.
You probably didn’t know this at the time but the camera in a typical cell phone can see that light. (You could have just had her look at it with a cell phone camera and push one of the buttons.)
I’d expect a little mirror in a purse he’d feel because it should be big enough. Of course as long as it’s directed at bare skin. The watch probably wouldn’t work because it’s actually round and would spread out the energy. (And it’s smaller to boot.)
My guess is it’s the hard surface, not the reflective layer, that bounces the remote signal. I have experimented with remotes bouncing off non-mirrored, not shiny, but hard, wooden walls, and they worked.
Kudos to your daughter, Lynn! That shows both more scientific aptitude in general, and more understanding of mirrors, than the typical college freshman (and no, I’m not exaggerating).
astro, thanks for the information about gamma mirrors-- I hadn’t heard of those before.
notsoheavyd3, with radio, the major issue isn’t the material (pretty much anything conductive will work), but with the size: You have to have a mirror significantly larger than the wavelength.
And constanze, we’re assuming that you can feel the radiant heat directly from the Sun, right? The only reason I can think of that the sunbather might not be able to feel it on his back, too, is that you’d probably have a smaller area illuminated. I’d still expect that he could, though.
It’s just that while I did reflect light circles of my watch face* onto the walls, I never experienced them on the skin, and neither other reflections of sunlight, so I’m unsure on whether the sunbather would feel it, or how much (depending on size, not quality of the mirror?)
the cheap Quartz watches have flat glass faces, though
walls that are not dark also reflect enough light to work. quality remotes provide more than one LED so that there are many reflected paths and it is hard to not have it work.