Science Buddies: "Ask an Expert"

I am doing the “Extracting Energy From Ocean Tides” Science project. I am having problems finding the model or toy boat propeller, 1 3/4-inch diameter with a 1/8-inch hole as it is not available in any local stores. Is there any online source or store I may buy it from?

Hi Riri1,

I'm assuming that you're working on this project:

https://www.sciencebuddies.org/science- ... cean-tides

This propeller has the 1/8-inch hole size suggested in the project materials list but the diameter is a bit smaller:

https://www.amazon.com/uxcell-Rotating- ... _dp_1&th=1

And here's one with the specified diameter but a larger hole size. You may be able to modify the central hole to make it work:

https://www.amazon.com/uxcell-Rotating- ... _dp_1&th=1

I hope this helps. Please ask again if you have more questions.

A. Norman

In the Extracting Energy from Ocean Tides Project, what do I do if I use a different model propeller size? Instead of a 1 3/4-inch diameter with a 1/8-inch hole propeller, I’m planning to use a propeller that has the 1/8-inch hole size suggested in the project materials list but the diameter is a bit smaller. Will I need to make any other changes in the holes or project itself?


Moderator note: I moved this post to the thread from your first post so the expert who has been helping you will see that you have follow-up questions. Please keep all your posts on this topic together! Thank you.

Hi Riri1,

No changes to the project should be needed if you use a smaller diameter propeller (such as the one mentioned in my previous post). In this experiment, you measure the rotational speed of the propeller for different rates of water drainage from a bucket. You're not comparing your propeller speeds with any others so the propeller diameter doesn't matter as long as the propeller moves when the water drains from the bucket.

I hope this helps. Please ask again if you have more questions.

A. Norman