After teaching Sunday School for years, I save and squirrel away all sorts of strange objects. One of those is empty toilet paper rolls. They come in handy for all sorts of crafts, and who knows how many projects. This time they came in handy for a science lesson as we learned in this law of momentum lesson.
(there are affiliate links in here)
Supplies needed for law of momentum lesson
wrapping paper roll (ideally, but you can get away with toilet paper rolls or paper towel rolls), packing tape, marbles of different sizes (or wooden beads like we used because I had some), measuring tape, scissors, Real Science 4 Kids physics lab notebook, Real Science 4 Kids Physics
Putting together our Law of Momentum lesson
First, take the toilet paper rolls and cut them in half. Your goal is to cut them out as close to as evenly as possible. Once you’ve cut them in half, start taping them together. Use the measuring tape to mark foot long increments to give you a reference for approximately how far the marbles go. I taped the edges of our track to help reinforce the track to stand up to our repeated marble rolling.
Now that you have this all set up, it’s time to start testing the law of momentum. First, we’re going to weigh each of your marbles or beads. Record that in your notebook, my kids came up with all sorts of unique names for each of the marbles. I’m not really sure why they came up with all these names, but they thought it was hilarious and very important for our law of momentum lesson.
Now roll each marble down your track. As you roll the marbles do your best to hit it with the same amount of force each time. This can be difficult to do, but do the best you can.
Record how far each marble goes along your track. Our glass marbles were unfortunately all about the same size, so there was not a large amount of different between distances traveled.
View this post on Instagram
Continue rolling each of the marbles and writing down how far they traveled. We discovered the wooden beads did not travel as far as the glass marbles. We got into a bit of discussion if that is because they were different weights, or because the beads had a hole drilled in them and therefore did not roll as well.
Once you’ve rolled all of the marbles, set a marble in the middle of the tube, and roll another marble towards it. Record the results of the impact. This is where those different sized marbles get particularly interesting because you can see the smaller marble has very little impact on a bigger marble for movement, but the large marble moves the small marble immense distances.
Kepe recording what you notice. Of course after a while their observations became less scientific, and more to the “what happens when I ram these two marbles together?”
So at that point our law of momentum science lesson became slightly less scientific, and a lot more yelling and crashing.
That was quite all right with me.
Looking at the Science behind the Law of Momentum
While we’re looking at this at a very rudimentary level and not getting into the math behind it, there are some fun videos on YouTube you can watch to go with this, like this video from Crash Course.
More great 7th grade ideas
This was an activity last year, but here’s a few more 7th grade ideas