Supersized Slow-Mo Slinky Drop

[Applause]

You know what's been popular, Rod?

What's that?

Our Slinky Drop video!

That is popular, isn't it?

Yeah.

Do you want to do another Slinky drop?

That's not a slinky.

This is a slinky.

That is an excellent slinky.

We should drop that one.

We want to see whether a long Slinky and where F A MERS up here, whether a long Slinky works the same as a short Slinky.

Because some people on YouTube don't really believe that it's going to work the same, or they want to see it.

We're about to find out.

All right, I'll go film it from the grass and you drop the slinky.

Fine.

Okay. [Music]

Here you go, Rod.

Did you see it?

Yeah, that was a good drop.

Did you get it?

I don't know. I think so.

We got to check the cameras.

Well, I think it tended to tumble as it got right down to the bottom, and I think it's going too fast and tumbling.

I think you better—we better do that one again.

We got to do it again?

Yeah.

All right. [Music] [Applause]

Oh, thanks, Derek.

Oh, not a problem.

I saw that it still tumbles when it gets to the end.

Yeah, it's clear to me that you wouldn't want to be sitting at the end of this under an airplane.

No, definitely not.

No, much better to actually have a parachute.

Exactly.

So what do you think about the explanations that have been going around on the web?

You know, people talking about the center of mass is falling with the acceleration due to gravity, 9.8 m/s squared.

Is that true?

Uh, yes, it is.

And then the bottom end—people are saying it's actually shooting up to meet the middle.

Is that happening, or what do you think?

Uh, well, in the rest frame, it's staying at rest, so you don't need that explanation.

And it almost makes the most sense just to consider in our frame of reference nothing has changed at the bottom until the top of the slinky compresses.

True.

Why not just take gravity out of the equation altogether and let's see what happens to a horizontal Slinky?

All right, let's have a look at that.

Okay, this was prepared by Rod earlier.

When I hit the right-hand end of the spring, the left-hand end doesn't move until the compression wave travels down the length of the spring and changes the tension at that end.

Yeah, so it's about the same thing as the slinky, but obviously there's no gravitational force involved there.

Correct.

Cool.

All right, well, thanks so much.

We have learned a lot about slinkies.

My pleasure.