Two Experiments on Gravity and Motion
The goal of using the lab sheets is to introduce the student to the scientific method. Do not be discouraged if the hypothesis or even the interpretation is incorrect. The hypothesis should simply be an educated guess, and it is fun to see how one's guess was incorrect.
If the interpretation is incorrect, this is a good opportunity to explain how even the best scientists have some error in their methods which can lead to incorrect interpretations. For example, the interpretation from the Gravity Experiment should be that the book falls faster due to the resistance of the air on the surface of the piece of paper in trial #1. However, when the paper is placed on top of the book or released as a crumpled ball of paper, the paper touches the ground at the same time. In trial #3, if the crumpled paper and book were not released at the same time, or in trial #2, if the paper's edges extended beyond the book, there will be error.
One of the famous stories of Galileo is the basis for this experiment. Galileo was an Italian scientist who lived from 1564-1642. At the age of 25 he was the professor of mathematics at the University of Pisa. He became convinced that Aristotle's theories about falling bodies were incorrect. Galileo believed in using the experimental method to test theories. According to legend, he performed a public experiment from the Leaning Tower of Pisa. He dropped two unequal weights simultaneously from the top of the tower. The weights struck the ground at virtually the same time. His research led to more experiments, which in turn led to his conclusion that gravity pulls all objects to the earth with the same acceleration. This means that when air resistance is eliminated, objects of differing weights will fall at the same speed. Galileo was bitterly criticized for his views. During this time in Italy, the Roman Catholic Church considered the teachings of Aristotle to be as authoritative as the Bible. Galileo's discoveries in astronomy also contradicted Aristotle's teachings. As a result, Galileo was tried by the Inquisition. He was forced to give up his belief that the sun was the center of the solar system and imprisoned in his home for the rest of his life. You can find the full story of Galileo through research at your library.
The Pendulum Experiment is designed to test Galileo's hypothesis that the amount of time it takes for a pendulum to make a complete swing is the same, regardless of the distance that the pendulum swings. Galileo first thought of this hypothesis when he noticed that a chandelier in the cathedral swung back and forth in the same amount of time. He measured time by comparing it to his own pulse!
Once your student begins experimenting with pendulums, he may think of new experiments to try. One possibility would be to set up an experiment similar to the Pendulum Experiment but to vary the length of thread used with the identical weight. (For the teacher's benefit, Galileo found that the square of the amount of time it took for the pendulum to swing over and back (called the period or T) was proportional to its length. If your student wants to show this, he should make several trials and then graph the results. The square of the period would be plotted on one axis against the length on the other axis. All the points plotted should form a straight line.) Use a blank lab form for your experiment.