Ok, this is one of those thoughts I have in my brain and that I can't quite get rid of.
It breaks down into a couple of questions. For the purposes of this, I'm aware that what eyes see is the reflection of light bouncing off objects, but I'm curious the impact on the visibility of both objects and other lights.

A. If eyes emitted any light, could they still see anything at all?
B. If eyes emitted, for example, red light, could they see everything except red items? What about red lights? Does this change if the light is green or violet?
B.1. If they can't red things would they just be invisible?
B.2. If they can't see red lights, would it matter if the red light they're seeing is brighter or dimmer, and would it still be an invisible/blank space?
C. I'm not sure how infrared interacts here but I know animals that sense infrared do emit it, is there a reason that's different, if it's different.

The internet is mostly not super helpful with this, since eyes don't emit light, just reflect it and look glowy, but yeah, anyway... thanks for entertaining my weird fixation.

My 5-year-old loves doing “science experiments” at home with me and her older siblings, but it seems that the online lists of experiments we’re choosing from are truncated to leave off all but the least dangerous activities. This makes sense for a lot of low-parental-involvement contexts, but I’m going to be directing and deeply involved in these experiments. And I want fire. Smoke. Sparks. I want to make these experiments feel adventurous so the kids get really excited about whatever we’re learning. Baking soda and vinegar volcanoes and elephant toothpaste just don’t cut it.

What experiments can you recommend using only relatively common household materials? Chemicals, candles, electricity, a stovetop, etc. (Assume that the experimenters will all be taking standard precautions, wearing PPE, and generally using the experiments as both an opportunity to learn about science and about the safety measures that go with science experimentation.)

Or if you know of any websites listing these more spectacular home science experiments, please share those as well.

Bonus if the experiments involve multiple possible outcomes that the kid can use pen and paper and elementary math to predict in advance.