Of all the planets in our solar system, there's exactly one that is less dense than water — meaning if you had a bathtub big enough, it would actually float. Which one is it? Mercury Mars Saturn Neptune None Helium is the second most common element in the entire universe. But here's a strange thing about its history: where was helium first discovered? In a deep mine in South Africa On the sun, before anyone found it on Earth Inside a meteorite that landed in Siberia In the bubbles of a natural spring in Iceland None Grab a banana from your kitchen. Believe it or not, it's very slightly radioactive. What's responsible for that? Pesticide residue left over from farming Naturally occurring potassium in the fruit Trace uranium absorbed from the soil The ripening gas they're treated with None Fill two identical containers — one with hot water, one with cold — and stick them both in the freezer. Under the right conditions, which can end up freezing first? The cold water, always — this is obvious The hot water can actually freeze first They always freeze at exactly the same time Neither — hot water never fully freezes None Venus is sometimes called Earth's "twin," but it has one genuinely bizarre feature you'd notice immediately if you lived there. What is it? It rains glass sideways A single day there is longer than its entire year It has no nighttime at all The sun would appear bright green None The Eiffel Tower is made of iron, and iron does a specific thing in the heat of summer. As a result, what happens to the tower on a hot day? It hums at a low audible pitch It grows taller by about six inches It leans noticeably toward the river It changes color from the expanding paint None Time's up
