Need 7th grade science help!

[coinkc]

My daughter has a project that has us stumped!

The assignment is to create a "submarine" that will float, then sink, then resurface without any outside intervention once it is placed in the water.

We are absolutely clueless how to even begin working on this! Any ideas are VERY much appreciated!

 

[Cindy B]

Look up baking soda submarine. I remember in the 6th grade science class I worked in (as a parapro) the science teacher did a similar experiement.

 

[clh2]

Does it need to be in water?

If you take raisins and put them in soda (i.e. or "pop" as they say in other parts of the country) , they will rise and sink. 7-UP works great because you can see them. I've helped out enough here...let her find out - there's lots of this info on the internet.

Or if nothing else - at least by finding this type of experiment, maybe she will think of other ideas on her own.

 

[damo]

This should help.
http://www.terrificscience.org/freeresources/lessonpdfs/magicalsub.pdf

 

[coinkc]

Thank you all!!!

Now she has a starting point and can go from there.

 

[amid chaos]

DD's submarine went to school this morning. she froze small stones and a cork in a small tube with water. She will pop the whole thing out of the tube and put it in the water. The stones will sink the ice cube and the cork and when the ice melts, the stones will stay sunk (They arent considered a pollutant...they couldnt leave anything in t he water that could be considered a pollutant) and the cork will rise to the surface.