Friday, August 13, 2010

Pressure!

Today students began class with a BrainPop on currents and took the quiz. Tim and Moby did an excellent job describing how currents affect global weather patterns. They also explained global water circulation in the global conveyor belt.Click on the photo for a better view.

Students took notes on dissolved oxygen and learned that there is less oxygen available in the water than in the air we breath (12 parts per million vs 200 pmm) and that dissolved oxygen varies with temperature. Cold water holds more DO, just like cold sodas have more carbonation.

Pressure is the weight of particles above you and increases with depth in water. Right now there is one atmosphere of pressure squeezing on all of us, but we are used to it, so we don't notice the difference. We may notice our ears popping when driving over Shenandoah or flying in an airplane when pressure decreases. Water is 800 times more dense than air, so underwater, pressure increases dramatically. Pressure increases one atmosphere with every ten feet of depth, so all you need to do is dive down the deep end of the pool and you will feel an increase in pressure to two atmospheres (one for the water, and one for the air)

Scientists think it is funny to take styrofoam deep into the ocean because the pressure underwater will squeeze the air out of the styrofoam and "shrink it." Really it is just compressed and more dense. Here is a photo of what happens to styrofoam wig-heads and cups when taken down a few thousand feet, a change of several atmospheres of pressure.
Brittany oversees the boys as Brendan, Brandon, and Bruce try to measure the water correctly

Students finished class with a lab demonstration of how pressure increases with depth using cups of water with three holes. Water squirted further out of the bottom hole because there was more weight and pressure pushing down on that part of the cup. Students did an excellent job working together and cleaning up.
Morgan removes the tape, Micheal holds the ruler, and all try to read the measurements
Carlton peels the tape while Corrinn, Courtney, and Cherie get their measurements
In this photo are Noel, Nate, Rachel, and Tommy
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Computer Lab Etiquette

You are in the computer lab to do work for this class. If you are not doing work, then we will have problems.

Do not pack up early. Work until the bell or until MsJ says.

SAVE OFTEN. And if you save to a key, also save it to your number. If you lose it, you will have to do it again.

If MsJ asks for your attention, stop what you are doing and listen to what she has to say.

You may watch videos about your organism through reliable websites.

You may listen to music through the computer if you have your own headphones. Rule1 MsJ cannot hear it. You get one warning. Rule2 Turn it on and listen – no million clicks and constant changing. Take both ear phones out when MsJ is talking.