Theme Park Discussion / Coaster Model

My next assignment in physics is to build a working coaster model. We (the class) haven't been given very many details yet, but we know that a ball bearing has to be able to complete the course without coming off the track. I'm kinda stuck when it comes to building materials, though. We're allowed to use anything we want, and it will be constructed in the classroom (which is fairly large) so that we don't have to worry about transporting it.

My idea was to build a grooved track that would guide the ball bearing through the course, but my friend/partner thinks that a semi-circular track would be better (like a bobsled coaster), allowing the ball more freedom in banked turns.

Any suggestions?

Your friends idea is better. Use PVC pipe cut in half. Your friends idea is better. Use some Knex cogs for the lift hill.

Have a look at pinball tables. You should get some good ideas there.

And listen to MA.

I like MA's idea. You could do the same type of thing with some sort of hose, for flexibility around in turns, hills, etc...

I like MA's idea. You could do the same type of thing with some sort of hose, for flexibility around in turns, hills, etc...

That's a good idea, too, and certainly cheaper and easier to use. You can get big coils of flexible clear plastic tubing for plumbing at a Home Depot or Lowe's. Dowel rods for supports?

Well it appears that you have peaked someone's interest, Xin.

Thanks for the suggestions, guys. I'll post pics as soon as we start building.

hit up your local home depot. flexible hose coil or vinyl tubing would do nicely.

You could use a combination of ideas, hose for the track, and use MA's pvc pipe for supports. They'd be super easy to glue together, enabling loads of possibilities and angles.

The vinyl tubing would have much higher friction, so I'd suggest using the PVC as often as possible, as it will have MUCH less friction slowing your ball down.

I'd say all of the current ideas here are good... I'm curious though, what is the goal? Is it like a competition where fastest time wins or just a project to do? Any limits on length, height, track elements, etc? I assume you need a working lift... K'nex are your best bet there probably.


We never got around to this but our physics class (of 3 students woot!) was going to a toothpick and glue bridge that has to support a bucket of sand. I wish we would have done it....

We just got the rubric for the project today. It is as follows:

Design: 5 points

Construction: 15 points

Passenger Experience/Success Rate*: 50 points

Time Log and Expense Account: 20 points

Summary Paper: 25 points

Modifications: 5 points

Creativity: bonus points for most creative coaster

Total: 120 points

*Success rate will be based upon 10 trial runs using a 3cm, 97g ball bearing. Points will be accumulated as follows:
-Each trial is worth 10% of the total points possible for that category.
-A break in the coaster will cost you 1% per minute to repair it. If the repair exeeds 10 minutes, points will be deducted from the next trial.
-A "touch" or a push will cost you 2% per touch/push.
-A "bypass" will be a deduction that is weighted on the feature.

By "touch," she means that you have to touch the coaster if the ball gets stuck. By "bypass," she is refering to the ball falling off one piece of the track and landing on another.

All the materials suggested and the one's I'll actually use are all acceptable building materials.

And it's due on December 11.

I did this in sixth grade! We also had to made loops and helices on our track. It was so much fun. The PVC pipe should work, but it will be annoying to cut and make curves with. We used a flexible foam pipe cut in half- sort of like a pool noodle but smaller and that allows you to easily make bends and elements- just use tacks to attach it to the wall.

All the materials suggested and the one's I'll actually use are all acceptable building materials.

...As in, you plan to ignore our advice again.

It's okay, though. It seems in your school, if your ball bearing falles off the track, kills a man, and lights the school on fire, you'll still get a B+.

http://www.youtube.c...feature=related

A "blue print," if you want to call it that. This only shows half of the coaster though. I had a bit of trouble scanning, so the second half of the blue print and the sketch will be posted tomorrow. For now, here's the first half. It's a big image (dimensionally, not file size) so you can see all my numbers and junk. Ignore the top right corner; my dog got a hold of my graph paper.



All comments are welcome.

Bahaha, I realized just now that my coaster layout looked like a penis with a prince albert...

Sketches:


I used:
1/4" Flexible Clear Tubing (rails) (Lowe's/Home Depot) (remember to dbl length of track since this is one (1) rail)
2'x4'x1" Foam Board (supports) (Michael's/Hobby Lobby/Etc)
2 Sheets Cardboard Paper (Used to glue tubing to due to foam board's rough surface and paint ir draw on to mimic wooden roller coaster supports)
Hot Glue
Big Piece of Plywood (base)

In my scenario, we didn't have to build a lift, but I did anyway (non-magnetic chain lift). All we had to do was make it ride-able, feasible, and reliable. My initial thought was to make a couple more helices, but due to height restrictions (3 ft, I think), we went with the above drawing. It's easy to make (although the drawing's above wouldn't let me visualize it in 3-d) and the calculations are simple to do (Height A minus Height B, plug that into the velocity equations: voila!). Only time consuming part on this is putting together the foam, but even that is simple with a Dremel, a jigsaw, or even a sharp knife.

In fact, the coaster model above was so simple, yet effective, it beat out the valedictorian/saludictorian team of the year ahead of me! My advice is to go with something simple, but flowing - not all whipping back and forth with 86 helices. It's boring to look at (imo) and it can become very hard to determine where the ball (car) gets out of control.

Anywho, that's my 2 scents.

Here's the sketch.


I'll hopefully get some construction pics up soon. We've drawn the full blueprint (in actual size) on a piece of plywood (and it's quite large), all the locations for supports have been marked (supports were added to the blue print after I scanned it), and some of the dowel rods have been cut to their correct sizes. When I get back to school, I'll use my art teacher's "hot wire thing" to cut the styrofoam into circular footers. We've also scapped the idea of using a rubber hose as track material (MA was right...), so instead, we're using a small wire-looking thing. We'll arrange three lengths of this wire-looking stuff in a triangle to guide the ball bearing through its course. To make sure the track doesn't bend too much, we'll be bracing it with popsicle sticks.

And finally, if we have time, we'll paint the track midnight purple and the supports a green color. I was also wondering if anyone could make a logo for me? We've christened the coaster "The Joker's Jinx," and I was wondering if someone could make a logo that I can print out and glue onto the coaster (or on a popsicle stick sign).

The wire is a *bad* idea, trust me. Your spacing will have to be more or less perfect -- too tight and the friction will stop the ball bearing, too loose and it'll loose energy and momentum as it bounces around.

-ACE

^ Yeah, wire bad.

And if you're looking for logos, try google.