Teaching Physics to a Three Year Old
If the title of this post hasn’t made you cringe, then you are probably in the minority. Most people that know physics are probably thinking it’s too advanced for toddlers to grasp, and the people that don’t know physics - or least don’t think they do - are having a few PTSD flashbacks to high school science classes and homework answers with weird names like Newtons, Joules, and Teslas (if you have a 3-year old today, then this Tesla was most certainly not the car). I fell into the first category, and never really thought I’d be trying to show my toddler anything related to physics this soon, but I’ve discovered how to make it relatable to her and also to parents who might think content like this is out of reach.
Henley, Lauren, and I would go to the park and throw the ball for our dog, Jax, and Henley would ask questions. This doesn’t seem like a big deal, because every kid asks questions. Kids are new to the world and have a question for every new thing they see. Usually these questions are pretty simple and straightforward and have a five second answer that satisfies even the most inquisitive toddler. Henley, though, can be on a different wavelength when it comes to learning and asking questions. Today, she wasn’t asking things like “can I go pick flowers?” or “why does Jax chase the ball?” or “can I wipe my nose on your shirt?” Actually she did ask the last one, but it was followed by more substantial questions like “why does the ball roll?” and “how does the ball go so far?” and “why does the ball roll downhill?” I found myself trying to give her honest answers, but also trying not to dig myself into a hole of explanation. Each time I started into an answer, I would catch myself introducing a topic or idea that she didn’t have any idea about. If I start to talk about energy and gravity then I also have to try and explain mass and acceleration and time, and there’s no way to make that clear and succinct for a three-year-old, right? I mean, we can just say the ball rolls because it’s round, it goes far because I threw it hard, and it rolls downhill because . . . it’s down. But none of these answers felt right to me. I felt like I was shortchanging my daughter with a sort of “band-aid” answer that didn’t fit the cut. Maybe it’s a little extreme, but I felt like I was lying to my kid by not telling her what’s really behind all of these phenomena. I needed to find a remedy and do it fast because she was sitting in front of me at that very moment, looking to me for an answer.
“Why does the ball roll downhill every time, Daddy?”
“Well Babe, it’s because of gravity.”
“What’s gravity?”
“Gravity is this ‘thing’ that pulls everything down on Earth. It’s part of physics. Ok let’s go play more ball!”
I’d done it! I had given Henley an answer and successfully side stepped having to explain concepts that would be far beyond her comprehension level. We went back to throwing the ball and watching Jax chase after it, only to stop, drop, and roll in the middle of the grass for some well deserved back scratching.
The next morning, I wake up the way I usually do – to the sweetest voice coming from the baby monitor, “Mommy, Daddy, I’m awake! I gotta pee!” So I get out of bed the way I usually do, quickly with my eyes still half closed, and I walk into Henley’s room.
“Good morning Henley!”
“Daddy, what’s physics?”
Crap.
In the moment, I am barely awake, my eyes still trying to focus, still in my pajamas (ever wonder why we still call them pajamas when it’s really a pair of shorts and a holey t-shirt you stole from your little brother 20 years ago, or is that just me?). Physics? Now? I regroup quicker than I thought with a little misdirection and remind this little lady that she had to pee pretty badly just a second ago. While I’ve bought myself a small bit of time, I didn’t realize how small until she started asking about physics again while she was peeing. I had a vision of “The Thinker” by Rodin pop into my mind. “This must have been his inspiration – deep thought . . .philosophical debate . . . existential existentialism . . .on the toilet”, I thought. As we both sit there sizing each other up for answers, I come to the only logical conclusion there is at this point – Henley will learn physics and I will teach it to her, and I won’t be holding back.
I had pre-emptively thought it would be tricky navigation getting the basics of physics through to a toddler, so I decided on starting slow with just the dimensions of physics. Physics studies the world around us, so we need a way to measure everything in order to see how it’s all related to each other. The dimensions of physics just define the measurables, and there are three of them that cover a large portion of physics that we see in high school and college. They are mass, length, and time. This became Henley’s first physics lesson:
MASS - how much of something there is
LENGTH – how far something is
TIME – how long something takes to happen
Simple, clear, distinct. Easy to grasp, easy to remember. Sure, we can get into more and more detail about these concepts, but this correctly defined the basic building blocks of physics with a simple way for a toddler to connect the ideas crisply and cleanly. While concepts are great, hands on knowledge and examples are the best way to drive home those concepts, so we started to go through some tangibles. When we talked about mass, we just had a discussion about big objects versus little objects and which ones had more or less mass. Then we grabbed our food scale from downstairs (Lauren is a dynamite baker, so the food scale is a must for certain recipes), and started to weigh out the mass of, well, anything really. Henley had weighed herself on a scale but now we could measure the mass of her turtle, BT, her flashlight, and even her flip-flops. Each one had a different mass and also a different shape, so when the flashlight had more mass than one of her flip-flops even though the flashlight was smaller, she had to acknowledge that mass wasn’t all about size. I winced a little bit, thinking this was the rabbit hole I was trying to avoid – explaining one concept that leads to another and to another - but Henley was satisfied with knowing that we can guess quickly by sight which item has more mass, but a measurement would be the final determination.
This couldn’t have gone any better, so I decided to continue. We talked about length, and how to measure items with a ruler if they were small and a tape measure if they were large. We also talked about distance being a length that might be too far for one tape measure to get a value on, but we could put lots of tape measures together to get a number for the distance. I’m pretty sure she envisioned dozens of tape measures all stretched to their maximums trying to talk with each other about how to measure the distance from one street to the next, because next thing I know she’s stifling a laugh. We measured the length of the same items that we had weighed, for convenience and continuity, and also saw that the way an object is sitting might make a difference on how you measure its length. Last we arrived at time, and I was floored internally at how easy it was to talk about time with my toddler. When I said how long it takes for something to occur, I think that was just about the entire scope of explaining time that I had, but it was great for Henley. I asked her to run to the door and back while I timed her on my stopwatch from my phone – 4 seconds. I asked her to go slower the next time and see the difference in time – 8 seconds. She was getting it! The higher the numbers, the more time it took.
This was going so well, and so simply, that I decided we were going to reach for a couple concepts that would bring it all together. Physics has its foundation in these measurables, but where it begins to really take shape is also where some of us start to get lost. I needed to be able to combine these different dimensions in order to create some new concepts and ideas to show Henley what she really wanted to know.
We added two more concepts to the pot, speed and acceleration. For these concepts, Henley got to see terms based on mass and time simultaneously!
SPEED – how fast something is going
ACCELERATION – how fast is something getting faster
For both of these concepts, we would have to use division, but I had already made up my mind that today was about physics and not division, so I was going to take care of the math for Henley and make sure she understood the physics. We measured that distance to the door and back and had her run it again while I timed her – 4 seconds. Only this time, we knew the total distance was 12 feet, so I did the division (distance divided by time) to get a speed of 3 feet per second. She loved it! Before I was even done with a high five, she was asking if she could do it slower and see what the new speed was. She ran, I measured - 6 seconds. New speed, 2 feet per second. The distance hadn’t changed, but the time elapsed did, so the speed changed. Henley was impressed.
We quickly ran through acceleration, saying that the same way time changes, speed can change too. Acceleration is just how fast the speed changed. This was harder to measure, but we already had two ways to go to the door, one fast and one slow. We timed the trips to the door and back and I tweaked the math to make sure a number was produced – all I had to do was take the speed and divided by the time again, or 3/4 of a foot per second per second for the fast trip, and 1/3 of a foot per second per second for the slow trip. This entire lesson was going so well and so quickly that I went for broke trying to put a cherry on top of this sundae and give gravity one more try.
Earlier, I didn’t give my daughter enough credit to process difficult information and be able to form a meaningful connection to any of it. Now, I knew the only problem with her learning this stuff would be me. So I told her that gravity is an acceleration, and the reason it exists is because Earth is so big (mass) and it spins so fast (distance and time). When something that big is moving that fast, it’s hard for anything else to pull away from it, so we call that thing that keeps us close to the ground “gravity”. Next came Henley’s favorite part of the lesson – testing gravity. While lying on her back placing BT on her feet, airplane style, Henley made a prediction. BT would go up, but gravity would bring her down again. Sure enough, when Henley launched BT in the air, she came crashing down on Henley’s belly, full of laughter, smiles and gravity. Now every time I ask Henley, “what makes BT come down, she replies confidently, “GRAVITY!”
With that, physics has become a staple of Henley’s weekly education, and we talk about things like energy, force, and momentum with the same basic approach that we did in this lesson. We never worry about the actual numbers, but we keep our sights trained on getting a couple concepts to stick while reviewing previous ones as well. In this way, physics can be relatable and remain within reach of both parents and students alike. Now you can take this lesson forward to your kids whenever they ask you why things fall!
*Printable physics lesson coming 4/11 - check back soon!