This afternoon in physics, the students got their first challenge to combine their experiments and their math. The teacher set up a Hot Wheels track for launching marbles off a table across the classroom, with a seemingly straightforward question: if you roll a marble off the track, where is it going to land?
Using a fancy piece of equipment called a “photogate timer” to clock how fast the marble launches off the table (and a much simpler piece of equipment called a meterstick), the students come up in pairs to get three pieces of information: the speed of the marble, the height of the table, and how far the marble launched before it hit the ground.
So far, they had just been doing word problems about projectile motion and how to calculate the time something spends in the air, or the distance it travels before it hits the ground. This is the first time they don’t have a word problem for their math: they have to look at a real-life situation and find out how to explain it in terms of math, without a worksheet to tee things up for them. Even for students who know their algebra forwards and backwards, this is a surprising challenge that gets them out of their comfort zones.
But with help from their classmates, they can predict how far the marble should go (according to their equations) based on how long it was in the air and the speed out of the gate. Now rubber hits the road: how accurate is their math compared to what they measured in real life? The metersticks come out, and my students get a pleasant surprise: the math really works! Most students got errors of around 5%, and one pair even got 0.4%! Considering that they didn’t account for air resistance, that’s pretty darn good.
I love this lab because it challenges students to make sure they know how to apply math to real life, outside of the comfort zone of a worksheet, and it then gives them a satisfying conclusion. Sometimes, it seems like physics and math is something that only works on paper… but now, they see that they can predict how the marble launches to 95% accuracy! It makes them feel like they can understand and use things in the world they couldn’t have before.
