# MacGyver Season 2 Episode 19 Science Notes: Benjamin Franklin + Grey Duffle

This is just the beginning of the show, so we don’t really know what’s going on except that Riley, Jack and MacGyver are on a trampoline supported by a bunch of balloons.

So, I will just leave this as a homework question for you. How many balloons would you need to lift 3 humans?

Resonance

Pinned down by gunfire, MacGyver needs a way to distract the baddies so that they can make their move. Angus takes his phone and plugs into an audio sound system and plays some high pitched song. This is the classic demo of singing to break some glass. Of course, that doesn’t usually involve a glass window—but still this is all about resonance.

If you go out to a playground, you can find a nice swing. If you push the swing at regular intervals, you can get the swing amplitude to increase. But here is the key point. The frequency of the pushes has to be the same as the natural oscillation frequency of the swing. Otherwise, your push might be timed at the bottom of the swinging motion which could cause the thing to slow down.

If you want to break glass with sound, it is indeed possible. Here’s what you do. Take some glass and give it a nice little tap so that it makes a ringing tone. Measure the frequency of this ring and then play that same frequency with a speaker—it’s got to be LOUD for it to work.

Of course loud noises and breaking glasses aren’t always safe. Here is an alternative demonstration with resonance. As a bonus, you can use this as a magic trick for your friends.

Detecting counterfeit money

They have all these 100 dollar bills. The suspicion is that they are fake—they are one dollar bills reprinted to be 100s. MacGyver puts them in an acid solution to dissolve the new ink as a test.

GPS phone tracker

MacGyver takes the gps receiver along with a battery from a phone and creates a tracking device. Of course the gps is actually built into the processor for most phones—so let’s just say he takes that whole thing (along with the LTE transmitter). Yeah, this would basically work.

Duffle bag battering ram

There is a duffle bag filled with cash. MacGyver hangs this up and uses it as a type of battering ram—to knock over a bad guy.

Bonus Homework

When MacGyver brings in the counterfeit money, he says:

“Yeah, well one million dollars in 100 dollar bills is actually only 20 pounds…so…”

OK—go. Check if this quote is legit. Here is some help. This is a post to estimate the size of a stack that contains 1 trillion dollars. I also use this as an opportunity to calculate the density for a dollar bill. https://www.wired.com/2011/09/stacking-one-trillion-dollars/

## 2 thoughts on “MacGyver Season 2 Episode 19 Science Notes: Benjamin Franklin + Grey Duffle”

This site uses Akismet to reduce spam. Learn how your comment data is processed.