If you look at the sun directly, the energy focused inside your eye will cook your retinal tissue and blind you . Measurements of the sun are made by exposing film of one sort or another. Usually the light is filtered somehow, or the film is not sensitive to certain light frequencies.

I am not too familiar with the chemistry behind film. There are also photoelectric methods of measuring solar light - this is where photons jolt electrons off of a surface, and we measure the electrons, just the way that a television screen does.

Do we look directly at the sun. I don't! Once there was a partial eclipse of the sun, and the students at Isla Vista School used a pin to punch a tiny hole in a piece of cardboard. They could put the cardboard in front of the sun and hold a piece of white paper a couple feet in back of the cardboard, in the same line as the cardboard and the sun. We could see the eclipse on the white paper. The sun looked like a cookie with a big bite taken out of it.

Once I went on a trip to see a total eclipse, and they gave us special VERY DARK glasses to wear during the darkest part of the eclipse. They weren't dark enough, though, to look at most of the eclipse, because the sun was very bright even when most of it was covered up by the moon.

Sometimes the sun isn't very bright on a cloudy day or when it is setting, and I can look at it if I squint so that only a LITTLE bit of sunlight gets in my eyes. But I don't want to do that very much, because I know that bright sunlight can damage my eyes; and scientists think that too much bright sunlight might make me more likely to be blind when I get old!