You will conduct experiments with freefalling spheres and manipulate three variables: mass of falling objects, gravitational acceleration, and height from which objects are released.
After completing this tutorial, you will be able to complete the following:
The Activity Object opens by discussing Galileo's classic experiment with falling objects. Galileo Galilei was born in Pisa, Italy, in 1564, and died in Tuscany, Italy, in 1642. He considered entering the priesthood when he was a young man but decided instead to study medicine. While working toward his medical degree, he changed course and began to pursue mathematics. Galileo eventually taught geometry, mechanics, and astronomy at the University of Padua in Italy. Throughout his career, Galileo made many contributions to mathematics and science and has been called "the Father of Modern Science."
One of Galileo's contributions came about when he climbed to the top of the Leaning Tower of Pisa and dropped two spheres of different masses but similar density and shape to the ground. He found that the two spheres hit the ground at the same time. Until then, it was commonly believed that heavy objects fall faster than light objects.
Not every pair of objects will fall at the same rate though. If two items are dropped from the same height and one is much denser than the other, the denser one will hit the ground first. If Galileo had dropped a lead ball and a wadded piece of paper of the same size in his experiment, the lead ball (with greater density) would have hit the ground first. This is because air resistance affects the paper ball more than it affects the lead ball. Additionally, air resistance will slow falling objects that have a greater leading surface. If a man without a parachute and a man with a parachute (with greater air resistance) jump from a great height at the same time, the man without a parachute will hit the ground first.
The Activity Object allows learners to do free fall experiments similar to Galileo's. However, experiments are conducted in a room in which all air has been removed to eliminate air resistance. Additionally, because this is a simulation, gravitational force can be changed. Learners explore the effects of mass, gravitational acceleration, and height on falling objects. When there is no air resistance, objects with the same mass fall at the same rate. The greater the gravitational acceleration, the faster the objects fall. When gravitational acceleration is constant, the greater the height of the drop, the longer it takes for objects to fall.
|Approximate Time||20 Minutes|
|Pre-requisite Concepts||Students should be familiar with force.|
|Type of Tutorial||Experiment|
|Key Vocabulary||acceleration, air resistance, constant|