Never Mind the Bullocks, Here's the Science (2 page)

That’s how NASA became linked to Velcro—
not
because NASA invented it.

And ever since NASA and Velcro got stuck together, nobody’s been able to tear them apart.

Wall-Jumping

The rather odd ‘sport’ of ‘Velcro wall-jumping’ involves running at a wall (sometimes bouncing off a trampoline) with the aim of attaching oneself as high on the wall as possible.

David Letterman made this ‘sport’ famous by performing it on
Late Night with David Letterman
on 28 February 1984.

Launching Makes Me Itchy

Each space shuttle uses about a quarter of a kilometre of Velcro. But even before 1981, NASA was linked to Velcro—and not because NASA invented it.

Cars and Spaceships

The first Velcro was made from cotton fabric. Because this material was too weak, it was replaced by nylon, with polyester sometimes added.

The Velcro used on the space shuttle is made with Teflon for the loops, polyester for the hooks, and the backing is made from a type of glass. In the UK, the Warwick Manufacturing Group is developing hooks and loops that are tiny – of the order of nanometres, or billionths of a metre. Car makers, including Jaguar, are interested in using the group’s idea to assemble cars.

References

Binney, Ruth (Editor),
The Origins of Everyday Things
, London: Reader’s Digest, 1998, p 130.

Freeman, Allyn and Golden, Bob,
Why Didn’t I think of That: Bizarre Origins of Ingenious Inventions We Couldn’t Live Without
, New York: John Wiley & Sons, Inc., 1997, pp 99-101.

‘NASA spinoffs: fact or myth’,
Invention & Technology
, Fall 2008, Vol 23, Issue 3, pp 38, 39.

Panati, Charles,
Extraordinary Origins of Everyday Things
, New York: Harper & Row, 1987, pp 317, 318.

Roberts, Royston M.,
Serendipity: Accidental Discoveries in Science
, New York: John Wiley & Sons, Inc., 1989, pp 220-222.

Schwarcz, Dr Joe,
Dr. Joe & What You Didn’t Know: 177 Fascinating Questions & Answers About the Chemistry of Everyday Life
, Toronto, Ont: ECW Press, 2003, pp 178, 179.

Water-Powered Car
(This Car is Hydromatic)

Once you get a bunch of hot-rod motor-heads together, sooner or later the talk will turn to the ‘invention’ of the ‘Car Powered By Tap Water’. This Big Conspiracy story always involves Big Business and/or Big Government. Apparently, in the recent (or distant) past, a poorly defined consortium of evil politicians and/or car manufacturers and/or oil companies suppressed this marvellous invention (i.e. a water-powered car) to protect their own interests. Even Conspiracy Theorists who don’t drive cars believe this myth.

It’s an attractive myth because it’s so simple. There are a few different versions.

1—Very Simple, Burn Water

The first version of this myth is incredibly simple. The story is that all you have to do is make some cheap modifications to your engine, or carburettor, or fuel injection system. You can then run your Internal Combustion Engine by pouring water (not petrol) into the fuel tank.

However, there’s a very simple and fundamental reason why you cannot power a car by burning water in the engine. And that is because the water has already been burnt, and so the chemical energy has been used up!

Let me explain.

When you burn coal in a furnace, the chemical reaction gives you carbon dioxide and heat. After the fire is out, some ashes remain. These ashes are the leftovers from burning the coal.

You cannot burn those ashes again—they have already been burnt.

Water Is Burnt Ashes

The situation is the same for water—i.e. the water has already been burnt.

When you burn hydrogen and oxygen in a chemical reaction, you get water and heat. When each NASA space shuttle thunders upwards into Space, its external tank carries about 617 tonnes of liquid oxygen and about 103 tonnes of liquid hydrogen. They are burnt together to produce about 720 tonnes of water—which is instantaneously turned into steam by the heat of the chemical reaction. This steam builds up inside the rocket engine with enormous pressure, and is released through the nozzles of the rocket engine. These nozzles point down to the ground. And so, thanks to the rule ‘for every Action there is an equal and opposite Reaction’, the space shuttle is pushed upwards—‘to infinity and beyond’.

After the steam comes out of the space shuttle rocket nozzles, it cools down. The gaseous steam turns into droplets of liquid water, which appear as a long skinny vertical cloud behind the rising space shuttle.

So when you start with hydrogen and oxygen, you can combine them to give you water and heat. Water might be ‘wet’ like petrol, but it has also been burnt, like coal ashes.

Think of water merely as wet ashes. It has already been burnt, so it can’t be burnt again (just like coal ashes—they have been burnt and can’t be burnt again). So you can’t get any more chemical energy out of the water, because the energy has already been released.

Who Put Water in My Petrol Tank?

A good conspiracy story always involves Big Business and/or Big Government. One great plot revolves around a poorly defined consortium of evil politicians and/or car manufacturers and/or oil companies who suppressed this marvellous invention (of a water-powered car) to protect their own interests.

No biggy…just a good ol’ water molecule (H
₂
O)

2—Pretty Simple, Burn Hydrogen

There is a roundabout way of producing energy out of this wet liquid water—and that’s the background to
another
version of the Run-Your-Car-On-Water myth. If you split the water back into its components, which are oxygen and hydrogen, you can burn them.

Scientists have been doing this for centuries. It’s so simple that you can build the mechanism in your workshop and install it in your car.

Pour the water into a tank that has a metal electrode at each end, and then shove some electricity into those electrodes. The energy in the electricity will split the liquid water (H
₂
O) into bubbles of hydrogen gas at one electrode and bubbles of oxygen gas at the other electrode.

Then there are two choices.

One is to run the engine entirely on hydrogen by burning it in the cylinders instead of burning petrol. It can be done, but it requires a lot of tinkering with the computers that run the engine.

The other choice is much more popular. As usual, fill the tank with petrol, and let it run the engine. But use the electricity from the alternator to split water into hydrogen and oxygen, and then pipe the hydrogen—and sometimes the oxygen—gas into the air filter of your engine, from where it gets sucked in and burnt. This will supposedly increase your fuel economy by up to 300%. But could this really work?

TANSTAAFL

Well, it is true that electricity will split water into hydrogen and oxygen, which can be burnt in the engine.

But the Laws of Thermodynamics stop you from getting energy for nothing. (By the way, the casual or layman’s form of the Three Laws of Thermodynamics are (1) you cannot win, (2) you cannot break even and (3) you will always lose.)

Yes, you can get energy from the hydrogen and oxygen, produced by splitting water with electricity—but you have to put more energy in than you get out. For example, if you put in 100 units of energy to split the water into hydrogen and oxygen, you will get back only (say) 80 units of energy when you recombine the hydrogen and oxygen.

Robert Heinlein popularised the Three Laws of Thermodynamics in his 1966 novel
The Moon is a Harsh Mistress.
He summed them up in one neat acronym: TANSTAAFL—which stands for ‘There Ain’t No Such Thing As A Free Lunch’. You won’t get more energy back than you put in, and thanks to losses (e.g. friction and heat), you will always get less. So, sadly, you can’t increase fuel economy by 300% just by adding hydrogen into a petrol-burning engine.

3—Myths Galore

Luckily for the Conspiracy Theorists, there are other sources of energy besides chemical energy upon which to base new myths. These include gravitational energy, kinetic energy, heat energy, electrical energy, magnetic energy and nuclear energy. However, nobody has yet succeeded in using any of these kinds of energy with water to propel a car with an Internal Combustion Engine. So perhaps it’s time to hose down such far-fetched ideas.

Combustion, Internal or External?

Why do people talk about the Internal Combustion Engine? Is there an External Combustion Engine?

Yes. Both the Internal and the External Combustion Engines generate work by pushing pistons inside a cylinder. And, in each case, pistons move because the gas (the working fluid) inside the cylinder is at a high pressure.

But in an External Combustion Engine, the gas is generated by having the burning happen outside the engine. The advantage is that it makes the burning very clean and efficient. However, there is a disadvantage – the extra weight of a separate combustion chamber. So, in a steam engine, the fire happens inside the boiler turning water into steam, and the steam is then piped to another location where the cylinders are.

In an Internal Combustion Engine, the burning happens inside the engine, where the moving parts are. In a jet engine the kerosene is burnt inside the engine – and the same goes for a rocket engine. And yes, the petrol is burnt inside the Internal Combustion Engine of an automobile. The advantage is the reduction in weight – but the disadvantage lies in trying to get a clean burn. Car engines were always ‘dirty’, until computers cleaned them up, by constantly monitoring and adjusting the burn cycle.

References

Allen, Mike, ‘The truth about water-powered cars: mechanic’s diary’,
Popular Mechanics
, 3 July 2008.

Allen, Mike, ‘Water-powered cars: hydrogen electrolyzer mod can’t up MPGs’,
Popular Mechanics
, 7 August 2008.

Brake Assist
(Padding the Facts)

Let me tell you the sad story of a friend of mine who smashed her car into the car in front of her. (Happily, nobody got hurt.)

Unfortunately, she wrongly believed that hitting the brakes as hard as possible was very dangerous.

O Woe Is She

In all her years of driving, she had never once braked flat out. On this occasion, she was adjusting her car radio in heavy traffic and had taken her eyes off the road to find the tuning knob. (It’s never a good idea to take your eyes off the road while driving.) When she looked up from the radio, to her overwhelming horror, she saw that she was about to smash into the back of the car in front of her. The car in front had slowed dramatically, without her noticing (because she was looking at the radio not the road).