Shrinking Cups

By Amy Wagner

So what do we (the scientists) do to entertain ourselves or remind us of our families at home during our “off” time at sea? Well, one of the things we can do is decorate Styrofoam® cups and send them down to great depths in the ocean.

We had a group of students from Knoxville Middle School in Knoxville, Iowa and Waukee South Middle School in Waukee, Iowa send us some cups they decorated so we could do exactly that. Below are some before and after shots of the cups. All we do is put them in a mesh laundry bag and attach the bags to the CTD rosette that gets lowered over the side of the ship. When they come back on board, they are about 50% smaller!

“Why does this happen?” you may ask. Styrofoam cups have a lot of air in them. When air is pressurized, it compresses. As you descend into the depths of the ocean, the pressure is immense. For every 10 meters you go into the ocean, an atmosphere’s worth of pressure is added. For example, if you dive down to 33 feet (10 meters), there is twice the air pressure than there is at the surface and at 330 feet (100 meters) the air pressure is 10 times that at the surface. Can you calculate what the pressure would be on these cups that are dropped down to 1000 meters?

Photos by: Amy Wagner

cups1                  cupsAmanda

Styrofoam cups attached to CTD frame.     Amanda Netburn with regular cup.

cupslittle             cupsAmy

Tiny cups!                                                       Amy Wagner with shrunken cups.


Side by side comparison (photo by Amanda Netburn)

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