Comments on: Episode 77: Birds in a Truck

By: Karl

Karl — Sun, 29 Aug 2010 13:58:35 +0000

Why do you think they have fins on the bottom of boats. To keep them going straight not going to work in thin air

By: Talyn

Talyn — Fri, 27 Aug 2010 03:35:33 +0000

Bifurcated boat:
Water also produces drag on the hull, this drag will add extra tension to the hull and allow it to split easier as there is already a great deal of inertial stress on the hull material… if there wasn’t the boat would go exponentially faster and not have to lift out of the water like it does when they ramp up the speed.
Additionally, the engine would serve to drive the boat further into the beam, increasing damage, and the wake would also fill in behind the boat causeing still more push. There is no way that a rail can simulate that… besides the rail would just force the boat to remain straight and not give a true test that way either.

Birds on a truck…
Air is not weightless, if the same mass exists inside of the truck and there is no way for that mass to easily escape, it does not matter how the mass inside that truck changes if it does not create impact or rebound upon the walls. the air is above the bird, the air is below the bird, same amount of air, same amount of bird. If the Birds crashed down, then gravity would add more weight/force upon the impact for a brief second, thats all I can see on those physics working. Mass Dissapearing would be magic not science.

By: johnm

johnm — Fri, 04 Jun 2010 02:45:55 +0000

Pigeons in a truck. Retest the pigeons in a cage built of lightweight kevlar strands woven to resemble hardware cloth or chicken wire (much lighter than metal mesh though). Now the birds are a larger percent of the total weight. The air from the birds in flight inside the cage wouldn’t be able to push down on the bottom of the cage, as the air would escape through the bottom and sides of the cage. This assumes the truck bed has blocks to raise just the sides of the cage sufficiently high so most of the down force misses the truck bed. Maybe some flappig bird tie in to the helicopter “hover in ground effect” principal?

By: marcus

marcus — Mon, 24 May 2010 07:27:51 +0000

This episode needs an epic revisit

By: Andrew

Andrew — Mon, 10 May 2010 13:18:03 +0000

the boat used in the test was not the same as the ? race boat that crashed early race hulls had a life span of one or two years due to lack of supporting bulk heads no built in bunks etc weight of race hull was aprox half that of production boat sold to the public with built in bunks etc and thicker hulls the model was closer to the race hull than the full size test hull

By: Mike

Mike — Wed, 28 Apr 2010 00:27:21 +0000

The pigeons in flight: Regarding the load sensors involved, in my recollection of how load sensors work, they output an analog signal representing rate of change (refer to piezoelectric crystals). Only when weight is being applied or removed from the sensor is there a signal change. Once a steady state has been achieved there is no longer a change in signal, whether or not the birds are on the floor or in flight.

An object approximating the total weight of all the pigeons should have been placed on the floor for a period of time and then observe the signal, remove the object, and after the same amount of time, observe the new signal.

As to the crashing boat, I think all of the above comments apply.

Very entertaining none the less. Thanks guys!

By: Brendan

Brendan — Fri, 23 Apr 2010 05:02:26 +0000

You need to do the boat test again. This time in “WATER”, for reasons already mentioned by others on here.

By: freddyzdead

freddyzdead — Mon, 08 Mar 2010 10:41:53 +0000

Grant: Your science teacher(s) failed you very badly.

This episode was very disappointing on all counts. Trying the boat bifurcation on anything but water is a moronic waste of time. Also, the manner and material of construction of the “myth” boat must be duplicated, else the whole test is meaningless.

Regarding the birds in the truck, all of the scales they used had far too coarse resolution to detect the tiny changes they were looking for. There were a lot of assumptions made, adding up to some very bad science. For example, they assumed that helicopters lift by blowing air downwards. They don’t. Helicopter rotors are airfoils, just like airplane wings. The lift is by bernoulli principle, not like a fan blowing down.

A good example was given above: Suspend a big heavy ball from the roof of a tall truck. Total weight = truck + ball. Let the ball drop. Total weight suddenly drops by weight of ball. Ball hits floor. Huge instantaneous weight increase, then total weight stabilizes at truck + ball. If ball hasn’t gone through floor.

Same principle for pigeons. Total weight = truck + pigeons. Slight increase in weight as pigeons take off, then weight = truck – pigeons. You would need a very sensitive scale to measure this.

By: Grant

Grant — Thu, 03 Dec 2009 22:42:57 +0000

I seen that one the birds in the truck i predicted the truck will remain the same.

Becuz the birds sit/standing was measured, and lets say that each bird weighed 200 Newtons…and they need exactly(but not really accurate) 200 Newtons to keep em floaking around(they cant go any higher)

so there (for each of them)downward force is gonna be 200 Newtons (exactly same with the helicopter)

By: Russell

Russell — Sun, 28 Jun 2009 18:17:35 +0000

After my previous comment, I realized I forgot to add that Kerri and Grant are both legends! I was only pulling the piss! Lol

Oh and Adam, I want you to do your Ozzy accent more!

It never fails to crack me up!

Adam is definitely one of the biggest legends the world has ever has the privilege of being entertained by!

Big ups to the A-star ;)