Get ready for the eclipse on August 21 and don’t fry your eyes!
Sunlight is dangerous, even if you don’t look right at the Sun. Sunglasses exist to protect your eyes from ultraviolet radiation, which can cause permanent damage, and even blindness. People who live in places with a lot of sun bouncing off snow have come up with stylish and effective protective eyewear – and all just to protect the eyes from reflected ambient light off snow and ice. (Snow blindness is effectively a sunburn on your retinas. OUCH.)While these snow goggles are stylish, and won’t freeze to your skin in really cold weather, you’ll need different techniques than normal sunglasses to view the Sun.
The reason they say never look at the Sun is that the light that can burn your retinas is invisible to the eye, and also emitted by the corona, which is not blocked during an eclipse. Also, your reflex to close your eyes to protect them from damage is tuned to visible light. So, if you look right at the sun during an eclipse, it would be too dark to trigger the protective reflex to blink, and yet those ultraviolet rays are busy frying your eyeballs. Nice. So: get appropriate viewing glasses.
Make a pinhole projector, and project the image of the sun onto a piece of paper. It’s super easy.
A Piece of Heavy Card Stock, or a Cereal Box
Scissors (for cutting the cereal box)
A Push Pin
Cut the back off a cereal box, or get a piece of card stock. Stab a tiny hole in the middle of the box piece. Go outside in the sunlight with your card stock piece and the piece of white paper. Place the paper on something still and flat, and hold the thin cardboard over it, so that it projects an image of the Sun on the white paper. You can safely look at this image of the sun on the paper all you want. You can even use this to see sun spots, when the sun isn’t being eclipsed. (Yes, studying sun spots like this is a really easy and cool science fair project.)
(And if it’s overcast, you can still watch the eclipse by weather balloon from the edge of space at this link.)
More suggestions for homebrew eclipse viewing devices on NPR’s Skunk Bear YouTube channel.
Happy Eclipse Viewing!