Science Buddies: "Ask an Expert"

i just finished writing my science research paper. im made the submarine from the project do submarines need fins? now when i put it in the water with fins on.... the fins turn upside down. can u put up a video showing how to do this experiment or can u tell me the desired results so i can chk if whats happening is right?
thanks,
maheen khan

In this particular experiment, it shouldn't matter whether the ruler you use for the fins sinks or floats to the top. Think some more about how the fins serve their purpose. Also, think about all the effects the fins have on the submarine and why it might happen that the fins would float to the top vs. sinking to the bottom.