I'm doing my schools science fair this year and I need to do something related to physics. After hurriedly coming up with an idea the day I needed one, I thought 'How much closer to physics can you get than newton's cradle?' (don't you dare say 'what about launching yourself out of a cannon?') I knew I needed something unique though and I thought back to last years science fair when a group made "quantum magnets" (which were really just superconductors). This gave me the idea of 'I'll just make a version of newton's cradle, but with superconductors!' But then I thought why stop there? why not REMOVE ALL THE FRICTION? So my next idea was to put them in a vacuum. I'll be measuring the efficiency of each of them. Yay, now you have my thought process of me getting into this.

So my project isn't going to be exactly like newton's cradle, but same concept. You roll a ball down an half circle, have it hit balls, have balls do physics stuff, last ball goes up the other side. (You can tell I'm in AP physics )

I'm going to have 4 half circles with surfaces made of 2 different materials. The first material will be just plywood or whatever I can find. The second will have the superconductors. (one of each type will be out in the air, the others will be in the vacuum.) I made a very realistic picture of it here.
* the grey box represents the vacuum
* the brown half-circle represent wood
* the grey half-circles represent the superconductors
* the arrows are for showing which direction the ball will go
* the colors of the arrows are for fun.


Now, everything has been going swell up until now. What my problem is, is I'm not sure how I can easily reset the half-circles that are in the vacuum. I cant just remove the vacuum, reset it, and run the experiment, that'd take too long and wouldn't work. I was wondering what is the best approach to this issue? I have a few motors, some buttons, an Arduino Uno, a Raspberry Pi, and tons of LEGOs.

Well, if you have an Arduino, you can probably wire something to work with those legos.

If you happen to have a LEGO Mindstorms brick thingie kit object, then you have a few easily controlled motors. You could even get a screenshot of your program (made in the included software) and have a nice visual.

How is the leftmost ball initially held?

So, a necro-macro post for a slight, massive change in plan.

I am in fact not going to use superconductors and probably not a vacuum either. This is because of the apparent difficulty of actually making a superconductor, you need a constant supply of pure oxygen, a kiln, and a few other things that make it really difficult. I don't have that kind of time. :\
Now you're probably thinking 'just buy one online!' and, wow, I didn't think about that, thanks for telling me!
***TheLastMillennial runs

Anyways, unfortunately the biggest (affordable) pre-made superconductor I could find was only 1/8 of an inch (.3175 cm) which is wayyy too small for what I'm making.

I'm also scrapping the vacuum because that's just adding unnecessary complexity to this project.

Instead of superconductors, I'm using regular bar magnets with aluminum guide rails to keep them on-track. This is a little disappointing since the whole reason I wanted to use superconductors is because I wouldn't need guide rails (which add lots of friction). To combat the friction issue, I've sprayed on silicon to the guide rails.

Now for the pieces of metal that will actually hit each other. They are going to be aluminum (since steel is magnetic) bars with smaller magnets on the bottom. Hopefully the magnets on each bar wont mess with each other too much, but if they do, I can just change their positions.

Here is me fine tuning the blocks:

And here is the incomplete, magnetic track.

I'm... finished? I think I'm finished. The project doesn't look nor work anything like I originally expected, but I was able to get some results out of it (with the science fair this Thursday) so I'm happy. Now I just need to make my poster look pretty because it's very ghetto right now.

Final beta


Thanks to an hour with Excel, the following graph makes me look like I know what I'm doing.
The graph shows the speed of the first (of only two since I couldn't get more than that to work) right before it hit the second collider in blue, the speed of the second collider right after it got hit in orange. Then I divided them to get a percentage of how much of the energy of the first collider was transferred to the second collider in grey.