Radar Mapping (Venus)

When we were studying Venus we learned about how some space probes used Radar Mapping to determine topography on Venus (since they couldn't see through the thick clouds). This seemed like kind of an abstract concept, so we talked about topographical maps and then I had the boys try some "Radar Mapping" of their own.

I just put some bowls into a shoebox and covered the box with paper so they couldn't see inside. Then we took a long skewer and marked centimeter markings on the side. The boys poked the skewer through the paper, observed how far it went in, and recorded their measurements on top of the paper. You have to remember to write down the number corresponding to the height of the object beneath, NOT how far the skewer goes in. In other words, I gave them a maximum height from ground to "cloud" (I think it was 11 cm), and then if the skewer went in 4 cm, we wrote down "7 cm" (11 minus 4) as the height of our mystery object. They caught on to that pretty quickly.

They had to make lots of measurements to make sure they were getting a good picture of what was underneath!

Once we had the paper full of measurements, I had them color it in with markers, using warm colors for the highest points and cools for the lowest points. Then I asked them to describe what they thought was beneath before we looked inside. They said "two mountains---one taller than the other."

Which was exactly right!

This was fun. They wanted to do it again, so they did it themselves for awhile during free time later that day.