The second has some old guy with a Steelers balloon
in a white van. No narration. No on-screen commentary. It was quickly filmed in one take with no editing for class discussion. The carefully worded science explanation is only visible if you read the comments below the video: Inertia of Air
Destin generally does a great job at SmarterEveryDay. He obviously enjoys life and covers eye-grabbing topics using slowmo cameras and collaborates with scientists and other YouTube personalities to popularize good science ideas. His recent series on the science of Winter Olympic events was excellent but "A Baffling Balloon Behavior" was disappointing.
Inertia is the tendency to maintain velocity
"Why will the balloon go forward?"
"Because all the air is sloshing back."
I know he's talking to kindergartners, but even he said "I know you're five, but I think you can get this" so why not use the proper explanation? The "sloshing back" terminology repeated several times by Destin and his kids implies that the air is moving backwards - it's not. Both the water and the air tend to stay in place as the jar or the van speed up from rest. The balloon moves backward when braking because the air tends to keep moving ("sloshing forward" works).
Acceleration vs. Speed
Just like Aristotle and most of us, Destin does not clearly differentiate between speed and acceleration - A "fast car" could be a car with a high top speed but is most often a car with good acceleration. "You have more air to breathe than Daddy does when I'm going fast" is a confusion of acceleration and speed. As you can see in the video, the balloon stays vertical when at a constant fast speed and only moves toward the acceleration. They do have more air to breathe when speeding up, but not when slowing down or turning.
What about turning?
As you can see in the second video, a hard left turn and the toy hangs right while the balloon moves left toward the center of the turn. Just a few more minutes of video filmed from the back window of Destin's van would have completed the idea with a demonstration for a two dimensional space. He could have talked about inertia (real) vs. centrifugal force (fake) and rounded out the concept with science even you can understand while doing donuts in a parking lot and avoiding light poles and snow piles from the long winter.
My Conclusion
- Edit and narrate your videos.
- Use other characters in your videos - your kids and your Dad and your friends and your cat
- Get the science correct and complete before you publish.
- Popularity does not imply good substance, even when from a trusted source.
Check out Smarter Every Day - Destin was weak on this one, but he does a great job of teaching science.
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