This Is What It Looks Like When Atoms Collide

This Is What Happens When You Hit a Nucleus

[mbyard]

I’m surprised that you didn’t mention the cosmic rays that were visible in the background. Quite a few shot past in those clips.

[NightRunner]

One note: The atoms don't just go away when they decay. They transmute into different elements in a pattern called a "decay series" or "decay chain". There are four of these; Thorium Series, Uranium Series, Actinium Series, which are natural processes, and the Neptunium Series which only occurs in manmade radioactive elements. They are so named because they follow the decay processes of the elements they are named after, and completely catalog each and every step along the process from original radioactive element to final stable end result element. Decaying radionuclides transmutate many, many times to many different unstable elements on their long, long journey toward stability. For some true perspective, consider that Thorium and Uranium are both naturally occurring radioactive elements abundant in the Earth, are older than the Earth itself, and are STILL decaying down toward stability.

Another fun fact is that you can make a smaller version of these "Cloud Chambers" using thermoelectric (Peltier) cooler modules. Stacking one atop the other and making sure the hot side is very well cooled gives ample temperature delta to run a miniature cloud chamber. I did one several years ago and documented it on my YT channel. It's truly fascinating to watch the streaks of high energy particles and rays in real time.

[annanimus]

OK, this was one of the best videos you ever made

[mickeyfilmer]

I remember seeing this experiment in the late 1960's when I was at school and the Physics teacher performed the experiment for us 11year old kids- that was it- I was hooked on Physics.

[johs]

Good to see that you break down the barrier between the obscure 'received' theories and what happens in reality. Very few are doing this.

[itiswhatitis]

Those real time particle traces are one of the most mindblowing things I've ever seen! Thanks Action Lab!

[adriano_omg]

"It's very simple. All what you need is a pure gold foil, a radioactive source, and a cloud chamber". I know it is indeed a quite simple setup, but saying it like this seems to be an ironic joke 😂

[MichaelLamar-zrfy]

You do some of the coolest experiments ever. The first one I saw of you was with the balloon in the back of the truck. I was blown away at that and I'm always in awe of what you show! So cool!

[Logical_Lobster]

Ideas to try: Use thicker piece and see what happens. Try two layers of gold foil. Try at an angle and see if it bounces off, or if it newton’s-cradle-refracts at an angle.

Measure length of trail with and without gold foil to see if either is longer. If a new alpha particle springs off the gold foil, it might reach further because it had a new starting point.

Excellent experiment!

[davidzaydullin]

this visualization makes so much sense! thanks for the video

[Slayceos]

I remember back when I was in high school we would leave for lunch and we would turn my friend's car into a cloud chamber

[asda-fhjn]

bro i swear in that rate you are gonna make a science musuem

[jonasgustavssonaland]

I wish I could have seen this visualization when we did labs on the radioactive decay in university.

[junkerzn]

Wow, your cloud chamber construction has really gotten good. What an awesome demonstration! This reminds me of an exhibit at Lawrence Hall of Science (in Berkeley California) that I really loved growing up... 50 years ago. It was a cloud chamber exhibit and with a little patience you could see the three patterns. The straight-line of a proton, the corkscrew of an electron, and the ghostly waviness of gamma rays. I thought it was super-cool back then and I think seeing people be able to DIY these experiments today is also super cool.

-Matt

[kyledodge]

Fun fact, a meteorologist was trying to make a cloud in a box, and instead got the first photograph of decaying particles

[CrimFerret]

We made one of these in physics class. It's always cool to watch. It bears mentioning that particle accelerators at their heart are basically fancy versions of this. They accelerate a particle beam, crash it into a target and detectors watch for the photon trails of the particles released. The way they behave in various magnetic fields and how long they last indicate what they are. It's like shooting a watch with a rifle and trying to figure out how the watch was put together based on the pieces that fly out.

[Stonium]

2:30 can you not point that directly at me? thanks.

[rohandrummer]

Brother. You the best! Youre right up there where it concerns practical demonstrations of experiments. Possibly the best in my books!

[tfrowlett]

I’ve been thinking of making my own cloud chamber, but in a different way. Dry ice is too expensive and hard to get where I live and Peltier devices are too power hungry to use for long. I was thinking of modifying an old ice machine as they have the evaporator on top already. All you’d have to do is remove the water pump and valve and disaible the thermostat or set it to its lowest setting and stick a metal plate on top.

[MatthijsvanDuin]

0:25 The space between nuclei is not empty, it has electron orbitals. They just don't really affect the alpha particles, because:
1. they're different fermions and therefore can pass straight through each other (no pauli exclusion), their only interaction is electrostatic attraction
2. the electrons are delocalized hence lack the steep electrostatic potential that the nucleus has (with associated strong electric field)
3. the huge mass difference means any interaction will mostly affect the electrons anyway and not so much the alpha particles.