Here they are learning about the heat of the sun, by concentrating its rays with a magnifying glass, to melt chocolate. We actually got the chocolate to bubble and smoke...Konrad almost burnt his tongue when he popped the chocolate in his mouth.
They covered two identical glasses containing the same amount of water, one with white paper and one with black paper, and then measured the temperature difference after a few hours (the black one was about 5 degrees warmer).
And we made a pinhole box to see the sun, safely. It wasn't as big as the enormous "solar eclipse machine" that Tom made this past summer, but here's Konrad pointing at the sun...
...and of course, being a boy, he puts the sun on his finger. What would happen with a magnifying glass? We didn't try that experiment!