Viscosity

• Viscosity is an essential characteristic of motor oil.Comstock/Comstock/Getty Images
  
  Viscosity is a measure of the resistance of fluid to flow and is an important principle in physics. In this project students measure the viscosity of various fluids and then demonstrate an important property of viscosity -- that fluids become less viscous as temperature increases. Set up four clear plastic 1-meter tubes vertically on a low table. Mark 1 inch from the top and 1 inch from the bottom of each tube with a thin ring of black tape. Fill the four tubes with water, salad oil, corn syrup and motor oil, respectively. Working in pairs, one student holds a stopwatch while another student drops a small steel ball into the top of the first tube to measure the time it takes for the ball to pass between the upper and lower ring of each tube. Students repeat this process three times for each tube, record the time in their lab notebook and compute an average. Then they lower the tubes into hot water for five minutes to warm the fluids. They raise the tubes out of the water and repeat the timing process again for each tube to measure any change in viscosity.
  
  

The Pendulum

• Foucault's pendulum demonstrates the earth's rotation.Photos.com/Photos.com/Getty Images
  
  In this project, students will learn about how kinetic energy is converted to potential energy in a pendulum. They will also understand the relationships between angle, mass, and length to the pendulum period (the length of time it takes for the pendulum to make one back-and-forth cycle). Set up three experiments -- recording the pendulum periods for five different pendulum lengths, five different pendulum masses (the weight of the object at the end of the pendulum) and five different pullback angles. Assign small groups of students to complete each experiment in turn, recording results for each variable. Ask groups to determine which variables are most likely to make the pendulum swing faster, and to estimate at what point the pendulum will have the most potential energy.
  
  

The Physics of a Roller-Coaster

• The principles of physics are demonstrated in many amusement park rides.Jupiterimages/Photos.com/Getty Images
  
  This project demonstrates Newton's first law of inertia: that objects remain in a state of rest unless they are compelled to change that state. It also demonstrates Newton's second law, that shows how acceleration is related to force and mass. Students build a roller-coaster of plastic tubing that will run a course that must include two hills and a loop before completion. The object can be a golf ball (measured for mass). The golf ball is impelled to start the course by the release of a spring placed at the top of the first hill. The force that finally stops the ball is friction as it rolls down the exit path. The exit path should be long enough for the ball to stop rolling before it reaches the end. Students must build a roller-coaster that give the ball all the kinetic energy it needs to complete the ride.
  
  

The Archimedes Screw Pump

• The Archimedes screw pump was invented in the 3rd century B.C. and is still in use today.Photos.com/Photos.com/Getty Images
  
  This project will demonstrate the principle of positive displacement pumps that operate by trapping a fixed volume of fluid from the inlet section and forcing it upwards into the discharge area. Invented in the 3rd century B.C., the Archimedes screw pump is still in use as an effective method of pumping waste water. Students construct simple screw pumps out of commonly available materials such as PVC pipe, vinyl tubing, duct tape and a retractable blade. They place two bowls 2 feet apart; one a few inches higher than the other. Place the Archimedes screw pump between the bowls at an angle and turn it. The mechanism will displace water from the lower bowl and transfer it to the higher one. Students run trials using Archimedes screw pumps of different dimensions, one with 1/4-inch clear plastic tubing and another with 1/2-inch tubing wrapped around a 1/2-inch PVC pipe. They calculate the average number of turns it takes to move a 1/2 cup of water from the lower to the upper bowl for each size and provide an analysis of the relative effectiveness of the pumps.