College and pro football games are played in all kinds of weather, from the early-season heat of August to the frigid playoff games of January. Fifth-graders can conduct experiments to see if temperature significantly affects the flexibility of a football. Warm a football in a hot sunny window, then drop it from a height of 5 feet. Measure how high it bounces by using a yardstick or tape measure. Next, place the football in a freezer for several hours and drop it from the same height. Note any difference in bounce height.
Games played outdoors often take place during windy days. For this science project, place one end of a 2-foot long board, such as a piece of scrap plywood, on a stack of several books to form a ramp. At the bottom of the ramp position a hair dryer so that it blows across the bottom of the ramp. Set the hair dryer to the highest speed but on the cool setting. Roll a golf ball, softball, baseball and tennis ball down the ramp. Determine how each ball is affected by the gust of wind by comparing the path each takes.
Baseball and softball bats come in different weights and materials. Devote a science project to determining if more energy is transferred from a heavy bat than a lighter-weight bat. It might seem like a heavier bat would be able to knock a ball farther. But you can swing a lighter bat faster, so when it hits the ball it will be traveling at a higher rate of speed. Place an empty 2-liter plastic soda bottle on a stool. Using a heavy wooden bat, swing and hit the bottle as hard as you can. Next, use a lightweight aluminum bat and then a plastic Wiffle Ball bat to hit the plastic bottles. Observe which bat lets you hit the bottle the farthest.
Friction between a moving object and the surface on which it travels is called traction. You probably know from experience that running on sand is much harder than running on pavement. In sports such as baseball, track and soccer, athletes wear shoes with cleats to get better traction. Locate a grassy area, such as an athletic field or park, and pace off about 100 feet in a straight line. Have a friend use a stop watch and time how fast you can run the distance wearing sneakers. Run the distance again wearing shoes with cleats. Compare the times to see if the cleats helped give you better traction, which results in faster running.