Buonancy and Air Pressure

Today in class we watched two simulations and also did a lab. Both of the stimulations had to deal with Archimedes and the Buoyancy effect. In the first one we made a prediction. My prediction was that the scale on top would get smaller as the weight hanging from it was submerged and the scale on the bottom would get bigger as the weight became submerged. My prediction was right. The scale read 9.0 as the weight was in the water but not touching the bottom. When the weight touched the bottom the scale was at 0. The bottom scale started at 200 and by the time the weight touched the bottom it had increased to 210. The second simulation was a beaker of water and you could put cubes in a container in the water to see how many cubes were be put in there until they would sink. It showed the water displacement on the side. You could also play with the width and depth of the container in which the cubes floated. We learned that the water that was displaced was the same amount of water that the cubes moved aside as they fell into the water. When we did the experiment we found there to be 100 cc weight of water buoyancy. When the width of the container is widened it could hold more cubes and this is how heavy iron boats can float. Their bases are wide but as you go up they get smaller. The experiment today was blowing a ping bong ball from one cup to another. This taught us about air pressure. We learned that air pressure is what moves the ball from one cup to another. This experiment also showed us that flowing air creates force which equals pressure. This lab showed us that the softer you blow on the ball the lighter the force and the harder you blow the more force. These activities would all be great ways to show students. The first two were great ways to demonstrate buoyancy. A lot of kids need a demonstration and they were quick but helpful ones. The lab was a great way to learn about air pressure. It was quick and easy but easy for the kids to understand.