Swimming In Syrup

Episode #119

OAD: May 6, 2009

Myth: Swimming In Syrup

Is it possible to swim as fast in syrup as you can in water?

The Experts:

Michael Mark provides the equipment to mix their guar gum ‘syrup’.

Nathan Adrian comes in to help with the swim tests.

Memorable/Quotable Moments:

Jamie: Pretend that you’re one with the syrup!

The Action/Results:

This is a physics puzzle of long standing.  On one hand, thick syrup will give much more resistance to a swimmer’s body.  On the other hand, the syrup will give much more resistance to a swimmer’s hand pushing back against it.  Which will have the most impact on a swimmer’s speed?  Jamie and Adam decide the only way to settle this is to fill a pool with syrup and go swimming.

However, they weren’t able to find a pool owner willing to let them pour syrup in the pool.  Instead, the guys head out into the California hills and excavate two pools, each 75 feet long and wide enough for a single swimmer.  Both are lined with four layers of heavy plastic, anchored by plywood decking around the edges.  One pool is filled with 10,000 gallons (37,854 liters) of plain water.  The other one is filled with a mix of water and guar gum that duplicates the viscosity of treacle or molasses.  At 1500 times the thickness of water, Michael Mark isn’t even sure the pump can handle it, but the syrup pool is filled with no problems.

Each of the guys swims three laps in the water-only pool, and the times are averaged.  Then they move to the syrup pool.  Both immediately notice that it’s harder to swim in the syrup, and they both get slower times.  Jamie is experiencing enough trouble from resistance that he cedes testing duties to Adam.

Adam would like to test some other viscosities.  This started out as a physics thought experiment, and as long as a given liquid is thicker than water it would count as a “syrup” in physics terms.  They run another set of tests with a guar gum mix that’s only twice as viscous as water, and Jamie runs the numbers.  In the heavy syrup, Adam swam 27% slower than in water.  In the thin syrup, he swam 2.8% slower, which falls within their margin of error.

The guys decide to run a third test, with a mix that would fit both the scientific and “average Joe” definitions of syrup.  At 500 times the viscosity of water, their new mix matches the viscosity of maple syrup.  They also bring in Olympic gold medallist Nathan Adrian, to see if he can get more consistent swim times than Adam.  In plain water, Nathan is much more consistent than Adam.  In the syrup, Nathan swims 9% slower, and there’s a greater spread to his times.  Nathan says he didn’t notice much more resistance at speed in the syrup, but that it was so different it threw off his technique.  Adam swam 5.4% slower in the syrup, and his times were more consistent than Nathan’s, something that delights Adam.

The guys agree to call this one Plausible; in the two lighter syrups Adam’s loss of speed was within the margin of error for their tests.

Myth: MacGyver’s Magic Bullets

Can you blow out the lock of a steel door with the powder from six bullets?

The Expert:

JD Nelson supervises the bomb range testing.

Memorable/Quotable Moments:

Kari, to Tory: OK, right now your mom is in my head, and she’s saying, “Don’t do that”.

JD Nelson: OK, the question is, do you want to do like a surgical kind of an entry around the lock, or do you just want to blow the crap out of it?

Rob: Hardly worth asking the question, really.

The Action/Results:

In one episode of MacGyver, Mac had to open a locked steel door.  He pulled six 38-caliber bullets apart, poured the powder into a scrap of cloth, and packed it into the lock.  He then jammed one of the empty cartridges into the lock, set off the primer with a blow from the gun butt, and the lock blew open.  Could this really work?

The team wants to start with a simpler test – could MacGyver have simply shot the lock open?  They set up a steel door in the bunker, and anchor a .38 handgun at point-blank range.  One remote-fired bullet later, Kari shoves the door and it opens.  So if it hadn’t been for Mac’s little problem with firearms, he could easily have gotten through the door.

Now it’s time to test MacGyver’s method.  First, Mac pulled the bullets apart with his bare hands to get at the powder.  Kari and Tory prove this doesn’t work; bullets are too hard to grip and too well seated in the cartridge.  Next, could he have set off the primer with a single rap of the pistol butt?  Each team member gets one cartridge, with powder removed for safety, and pounds away at it.  The bottoms of the cartridges get severely battered, but none of the primers go off.  The primer is flush with the rest of the cartridge, setting it off requires a focused blow from a firing pin.  Before testing moves to the Alameda bomb range, Kari mounts a pin of the same size into the butt of a handgun, and Grant builds a remote gun-swinging rig.  Meanwhile Tory measures how much powder MacGyver had to work with – six .38 rounds contain a total of 30 grains of powder.

At Alameda, the door is set up and Grant’s rig attached.  The first test is exactly as per the scene – 30 grains of gunpowder is wrapped in a piece of cloth and placed in the lock.  An empty cartridge goes in, and everyone moves behind the blast screen.  Grant’s rig works, setting off the primer, but the powder does not ignite.  Tory thinks the cloth may be shielding the powder, so he rearranges the components to put the powder in direct contact with the primer.  Once again, the primer fires but the powder doesn’t.

Grant suspects the powder may be the problem.  They’re using modern smokeless powder, but older .38 rounds were filled with more energetic black powder.  A third try with black powder finally sets the powder off, but it’s not enough to break the lock.  Finally, they ramp things up with 600 grains of black powder, enough for 120 bullets, and enough to fill the lock halfway.  This time, the door finally blows open.

This myth is Busted.  While it’s possible to blow open a lock with black powder, MacGyver’s method would not have worked.

For the Mandatory End-Of-Episode Explosion, the team sics JD Nelson onto the door.  One C4 charge later, and they don’t need to worry about packing that door up and hauling it back to the shop.

Myth: Davy Crockett’s Magic Bullet

Could Davy Crockett really have split a bullet in two by shooting the blade of an axe?

The Expert:

James Mitchell gives the team a refresher in muzzleloading rifles.

Memorable/Quotable Moments:

Tory: All we have to do is shoot the axe head with a bullet and split it in two.  How hard could that be?

Grant: What are we going to do with the rest of our day?

The Action/Results:

Frontier legend Davy Crockett was known to be a good shot, but was also known for stretching the truth.  Which of these is behind his claim to be able to hit two targets by firing at an axe head and splitting his bullet in two?  The team decides to just test the bullet-split part of this story.

They meet firearms expert James Mitchell at the range, and he goes over the procedure for loading and firing their reproduction 58-caliber muzzleloader rifles.  Once they’re sighted in with watermelons, soda bottles, and tomatoes, they set up the real target.  One blade of a double-bitted axe is sunk into the target, and paper stapled around it to show bullet hits better.  The team will be shooting at the exposed blade.  Davy Crockett claimed to be able to make this shot from 40 yards (36.5 meters), so that’s where they set up.

Tory is up first, and takes three shots.  His third one glances off the axe head.  Given enough practice, he thinks he could hit the blade dead on.  However, they don’t have time for that much practice, so they move in to 20 yards (18.3 meters) from the target instead.

Kari takes four shots from 20 yards.  Her last two graze the axe, but she doesn’t get a direct hit on the blade.  They’re running out of daylight, so Grant uses a couple sandbags as a rifle rest.  He comes even closer, but can’t make the shot.  Before they hand this myth off to James Mitchell, Tory asks if he can take one shot from the sandbags.  On this shot, Tory hits the axe head dead on, splits the round, and Confirms this myth.