Science Buddies: "Ask an Expert"

Hi Everyone,

We desperately need some help here. I'm trying to help my daughter create a self propelled boat for school. She is only able to use the following materials:

- 4 eggs
- 4 popsicle sticks
- 2 elastic bands
- 1 soda can
- glue

At this point, we think that we need to use the sticks and the elastics to create propeller. We're also thinking that we need to drain the eggs (can this be right?) and use them as them as the base of the boat, similar to a pontoon boat. We can't figure out how to put anything together as we cannot use any additional items whatsoever. Any thoughts or suggestions?

Thanks in advance!

Sounds like a fun project.

Break it down into the things you need to accomplish:

1.) A craft that floats:
The eggs can be drained by poking a very small hole in both ends, blowing out the contents, then sealing the holes with glue. In a similar fashion, the coke can can be opened, drained, and sealed for floatation. If you can choose the glue, you can pick a glue that could work for the eggs, popsicle sticks, and coke can.

2.) A method of propulsion:
The popsicle sticks can be made into a propeller, or perhaps better, the coke can can be cut into a paddle wheel. Your propeller can propel either air or water.
Also, perhaps you can fling the eggs backwards with the rubber band, and the Newton's third law would dictate that the ship would move forward.

Just some quick ideas. You could try a google search on rubber band powered boats for some other ideas.

Anyone else with some fun ideas?

Also, cutting the coke can into strips can give you quite a lot of structural material, with negligible mass.

Hi ScienceDummy!

You might want to check out:

http://www.asme.org/Events/Contests/Ide ... o_Boat.cfm

They had a larger materials lists than you had, so the post is not directly applicable. The Engineering Principles section provides some useful background.