So here is a particle that was shot through and it's knocked an electron out of an atom.
And by having a magnetic field around the bubble chamber
it bends the path of the electron
because the electron is negatively charged.
Things don't change direction of their own accord.
Things like to go in a straight line unless you influence them.
If you make a magnetic field, negatively charged particles will go one way,
and positives the other.
Neutral particles don't leave any trail at all in these pictures.
Now let's look at the next picture.
If you really turn on the magnetic field,
your electron will spiral round and round and round and round.
As it slows down the spiral gets tighter and tighter and tighter.
It looks like the picture of a snail from the top or something like that.
Now let's look at the next one.
Now this has got a lot of information. It's a beautiful picture.
At this point here an electron's been knocked out of the atom
and shoots off very high speed curving very slightly.
I know it's high speed because when you go fast you only curve a little bit.
If you go slow, you'll curve all the way around when you get given the sideways kick.
But look at this. Here's an electron that started off slow.
It's really gone into a very tight spiral.
But on the other side there's the same thing going the other way.
Negatively charged particles go one way, positives go the other.
This, the red trail at the bottom, is a positively charged electron.
The exact mirror image of the regular negative electron.
It's an example of antimatter.
Captured here on film.
This is antimatter, it's as real as the electrons are real.
Now over here, an electron and its antimatter partner,
which is called a positron by the way, is produced.
But between here and here, nothing appears to have happened.
These appear to have appeared out of nowhere.
Well that doesn't make sense at all.
What's happened is that something without any charge at all
has gone from here to here and left no trail.
But we recognise he was there the moment it did this.
So, we've got the steps in deciphering the pictures,
Let's look at out original picture again and see if we can make sense of it.
OK, well this very faint circle here is just an electron kicked out of an atom.
Like the first part of our three pieces of the jigsaw puzzle.
At this point here we see a whole series of negatively charged particles
curving off that way, and positives curving off the other way.
Then there's a gap where something without any charge at all must have gone
And it reveals its presence when it turns into two particles that do reveal themselves.
So, that shows you how you begin to decipher the picture.
But in this picture there's something very interesting. This gap here.
A particle without any charge must have lived
and for a very, very short time.
Let me show you what I mean.
I've got this little clock along the bottom.
This is the spot where this neutral object was created.
And that's where it died.
Now what's this clock doing?
Let's just think what happens in this thing here.
We've got this bubble chamber and the camera taking photographs.
There's particles shooting in from one side, almost at the speed of light.
They are across the bubble chamber in a flash.
But the camera takes the picture, it's probably for a thousanth of a second.
Which is a short time to you and me,
but it's a long time to a particle that is moving near the speed of light.
It's as if the particle enters this side of the bubble chamber and the clock starts.
By the time it's got to here, the clock is just passed the starting point.
By the time it's got to here, it's a millionth of a second later.
By the time it's got to here it's four millionths of a second later
and then it exits on the other side.
But the camera shutter has been open all the time.
And it takes what appears to be a still photograph as you see here.
But in fact it's a timelapse.
The time is running from one side to the other.
So between here and here it's maybe a millionth of a second or less.
So this picture has captured the passage, the life and death of a particle,
that lives for less than a millionth of a second.
It's astonishing to think that with this simple device
you can capture short, short timescales and make them for real.
And that is as important a part of the universe as everything else.
We've suddenly opened up sections in time here.
With our naked eye we can see a rainbow from red to purple
but we can expand right the way across the electromagnetic spectrum
and see the great universe out there.
Here suddenly we've expanded our senses in time to the very, very short.
These new unexpected short-lived particles are as relevant to the universe,
are as real to the whole picture, as the things that live long enough to make you and me.
And any rational explanation of the totality must include them.
And that's the big challenge.