Simple experiment for Dad's a Wonderful Experiments When you've lost your current car park and count five, I want to talk about my key form on central locking device on it, and you press this button and the lights flash.

I'm The point is that this sends out an electromagnetic waves.

The frequency of these waves depends on whether you get a car in North America or elsewhere.

For one, it's about 320 megahertz.

I can't remember the exact details.

The other is about 403 100 megahertz means that the wavelength of these electromagnetic waves is about a meter.

It's about so big Navid.

The whole point is that this has a range.

If I walk away from the car, the signal coming out gets weaker and weaker and weaker.

And there's a clever trick, which I found on YouTube with Jeremy Clarkson in top gear, explaining that if you have one of these key things the central locking device, the range can be extended if you place the key against your head.

I really wanted to know where this is true, but I I couldn't believe it.

So what I want to do today is to explain how it works.

But first, I must show you that it works.

12345 That's 20 paces.

If I use this.

You see, even with my arm extended, I can get the lights to turn on.

Now go another 15 paces this way and show you the car won't.

Lights won't go unless I put this against my head.

So here we go.

123 50.

Now, if I press the key, nothing happens.

But if I press the key placing in next to my head, something happened.

Now, the reason this works is because everybody's brain everybody's head is full of water.

So I got over there some water which are going collect on.

We'll go another 20 paces that way and show you that the water will extend the range even further.

So just don't go away from it.

I get it.

You think this is gonna be insane enough?

12345 Even when I get here, the lights will flash.

Ah, I must get away from the water.

We're just about at the limit of the range off Using your brain doesn't work now then I can't hold it.

That's pretty way up there.

I'm pressing now.

There we go.

When the electromagnetic waves goes into the water, all the water molecule see more or less the same electric fields sloshing through it.

The electric field moves the positive charges.

That is the protons or the hydrogen ions.

Well, boy on the auction irons, the other.

So in effect, what you've got is two protons being pushed up puts, then pulled downwards and pulled upwards and downwards.

Because of this oscillating electric field, that means that they're behaving rather like a radio aerial.

The electrons are going up and down, up and down, radiating energy.

Now, if I point my key that way there is a ray going straight from me to the car.

But it's also going into the bottle of water over here, or my head over here on the water in my head is going up and down in synchronization with the rays coming out of this because you're so close together.

If there are half a wavelength, you'd be completely out of phase.

But because you're close your interface on these waves add together the wave coming from my key, the waves coming from the water in my head or from the water in a bucket.

And that's a reason why these two add together and extend the range of my car.

There are obvious parallels with this in physics in the everyday world.

This seems 31 of the few that I everybody can play around with because they have these lovely keys central locking devices for their cars.

So you could do experiments at home.

I didn't believe it.

And the only way of finding out whether something is true is to do that.

The damned experiment.

Do the damned experiment.

Find out what is reality.

Disprove your prejudices, okay?