What is your first memory of science? If your first thought is a classroom, think farther back. What about a visit to an aquarium or a zoo? Or the first time your parents explained why or how something works? Think back to your Easy-Bake Oven – chemistry! – or collecting fireflies – biology! – and you’ll start to see the hidden signs of science all around you.
Like, say, learning to ride a bicycle. Did you ever wonder how it stayed upright? Yes, that’s science at work. Bicycles are science wonders, get them rolling fast enough and they stay upright. You could even roll one away with no rider and the bicycle would still stay upright! The how of bicycles is attributed to gyroscopic forces and the location of the steer axis – or at least, it was attributed. A new study (“A Bicycle Can Be Self-Stable Without Gyroscopic or Caster Effects”) removed both those features, and guess what? The bike still stays upright (as long as it’s moving faster than 7.5 ft. per second). The study also included a long history of popular explanations for bicycles’ stability, most of which dated back to more than 100 years ago! (So, when you wondered how a bicycle stayed upright, you were not alone.)
Bicycles are still a mystery but there’s another childhood toy with a clear physics explanation: the yo-yo. Yo-yos are very simple toys (a length of string attached to a spool) that have been around for a long time (the ancient Greeks played with yo-yos more than 2,500 years ago!). Here’s how they work: while you hold the yo-yo, preparing to drop it, the toy has a certain amount of potential energy. When you let the toy drop, the potential energy is converted into kinetic energy (energy of movement). As the string unwinds and the spool spins, the yo-yo gains angular momentum (movement of rotation), which keeps the toy spinning when it reaches the end of the string. The yo-yo rewinds when you jerk on the string – that increases the friction between the string and the spool’s axle, causing it to rewind on the axle. (So, if you ever dropped a yo-yo and it did not rewind, now you know why!)
Bicyles and yo-yos are not the only toys with science explanations, check out the chemistry of playdough, the flight patterns of boomerangs, the chemistry and biology of mood rings, or the inner workings of BB guns. So, let’s try that first question again. Think back to the first time you marveled at how something worked and tell us, what’s your first memory of science?