Class 10/23/08

In today's class, we covered density, pressure, and force. Dr. E gave an example of airplane wings. She said that velocity above the wings is slower and velocity underneath the wings is higher. We also talked alot about density today. Density= mass/volume. Dr. E gave a great example of density by describing clay. If you break a little piece of clay off a big block of clay, it is still the same density, it just has less volume. We also learned that lead is one of the most dense substances. Next, We did a mini-lab to find out how to put the most pressure on a sheet of paper using your body. Our group found out that if you stand on one leg on your tip-toes, you will apply the most pressure to the sheet of paper (16.129 lbs of presure per square inch). A practical example of pressure is massage therapy. If a massage therapist uses her whole hand on your back, it will not apply as much pressure as if she were to use her elbow or her thumbs. Overall, I learned alot about pressure and density in today class session.