Weight and Volume
In Investigation One, students will begin their study of weight and balance by exploring how balance is dependent on an even distribution of weight. They will build a model of a beam balance and learn how to balance the weight of the beam on the fulcrum. Students will vary the objects placed on the beam and observe the results. Through experimentation, they will learn that balancing a beam can be accomplished by moving the objects on the beam or moving the position of the fulcrum.
Students will continue their exploration of weight and balance in Investigation Two. They will be introduced to a pan balance, which is used to compare the weight of objects, and compare it to the beam balance. They will learn to equilibrate the pan balance before using it in their experiments. Students will then use the pan balance to compare the weight of several different objects. They will determine which of the objects are greater than or less than the weight of other objects. Students will also observe that the weight of an object is not related to its size. These experiments will assist students in understanding that weight is a physical property they can use to identify an object.
Investigation Three introduces students to another physical property of matter – volume. This investigation provides them with the opportunity to discover that the volume of an object is not dependent on the weight of that object. Students will use the pan balance to compare several foods that are equal in weight. They will determine which of the foods are greater than or less than in volume than the other foods. Through their experiments, students will observe that objects that are equal in weight may not be equal in volume.
In Investigation Four, students will examine whether objects or substances that are of equal volume are also of equal weight. Through the use of the same three foods used in the previous investigation, students will compare equal volumes of the foods on the pan balance. Students will discover that equal volumes result in different weights. They will determine which of the foods are greater than or less than in weight than the other foods. Through experimentation, students will observe that objects of equal volumes may not be equal in weight.
Investigation Five is designed to give students the opportunity to explore the properties of another state of matter – liquids. Students will observe equal volumes of three different liquids and compare how they look, feel, and smell. They will determine that although liquids have similar properties, they may be different in other properties. Students will then use the pan balance to compare the weight of the three liquids. They will determine which of the liquids are greater than or less than in volume than the other liquids. Through their experiments, students will observe that liquids have weight and that equal volumes of a liquid may not be equal in weight.