Homework problems were reviewed and corrected. The concept of a gravitational field was presented and demonstrated using magnets and iron fillings. The presence of a gravitation field, no matter how great the distance between objects was stressed. The use of the formula to determine the gravitational force between objects was used to solve problems. The theory of "weightlessness" was examined, and determined that it involved not weightlessness but a lack of a support force. The acceleration due to gravity was shown to be zero at the Earth's center