Help for Rock Skip Science Fair

[deleted-603201]

Hey, so I need help for science fair. My idea is to see which angle of the rock relative to the water or which angle of the path of the rock relative to the water makes a rock skip faster. I want to make a machine that can skip rocks, as well as be able to change the arm or wrist angle, but I don't know how. My main idea is having a "arm" made out of wood and having it connected to a pivot point to a base, so it can swivel. Then, I would attach a string or something on the other side to pull it back. But I need something to make the piece of wood go forward after its pulled back. I'm fairly sure that is possible. Anyway. Send Help. Please. For reference, see Mark Rober's video "Rock Skip Robot- The SCIENCE of PERFECT ROCK SKIPPING". Cool. Thanks.

[LeungWilley]

Hi Original,
This sounds like a great / fun experiment!

Unfortunately, I am not sure that I have ever seen plans for rock skipping machine. I was thinking that you may be able to modify some of the DIY pitching machine design to make it work with rocks though:

Here's a couple of examples with plans:
https://www.instructables.com/id/Pitching-Machine/
https://www.instructables.com/id/How-To ... -Launcher/

Good Luck and Have fun with the experiment!
Willey

[deleted-595119]

Hi!

I also saw that video, and I was amazed by what Mark made. I think his project was very cool, and I believe you could make it. Firstly, however, I think you should figure out what your experiment will be. I think that measuring the speed of rock is something that would be very difficult(even though it is possible). This is because the rock gets slower everytime it bounces. Something easier to measure would be the distance the rock goes, the number of skips, etc.

Secondly, you could follow Mark's way of building the machine. However, this may be difficult/dangerous for your age. If you decide you want to continue with this, make sure you have time and an experienced adult to help you. You could even follow Willey's great ideas to make a ball launcher.

I definitely think Mark's idea is great, and if you have the resources/time, you should make it. Don't be discouraged. Engineering is a process with failures that lead to successes. However, there are alternative ideas you can do if the rock skipping project as a last resort. You could make a projectile launcher and control the angle. There are many examples of this on youtube or the internet.
This is one of them:
https://www.youtube.com/watch?v=tMHYqxouBT8



If you have any questions, feel free to ask them. I will try to help to the best of my ability.

Good luck and have fun!