From the brains behind brains on, this is the moment of umm.

Answering those questions that make you go. Oh, um, um, um, um, um, um, um,

uh, uh, uh, uh, uh, uh,

uh, uh, uh, uh, mam, um, mam. The moment of um comes to you from 8 p.m. studios. I'm Mark Sanchez. Do you remember when you first learn to tie your shoes?

Lots of us wear slip-ons or shoes with

Velcro these days so maybe you never even learned. Don't worry it's never too

late. But it can take a while to get the hang of it. Sometimes you might tie your laces too tight and make a knot that's super hard to

untangle. Or sometimes you might leave them too loose and they come untied. It's so annoying to be walking along, happy as can be, and then, whoops, you trip on an untied shoelace.

Ah, didn't I just tie that one five minutes ago?

One of our listeners wanted to know why this happens.

Let's take a listen while I re-tie my shoes.

My name is Nahn from Bellevue, Nebraska.

My question is, how do Sioux Liceus come untied. untied.

So there's two things that contribute to your

shoelaces coming untied.

There's the fact that you're swinging your leg

back and forth as you take a step, and there's

also the fact that your foot is impacting the ground, and that impact is shaking up the

knot and causing it to loosen.

Hi, my name is Christine Gregg, and I'm an engineer who studies how things move and break.

I was really excited about this question because it's something that I deal with all the time.

It's one of those fun mysteries that we find in our everyday lives.

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