Investigation One introduces students to the idea of using models to study and make observations of things that may not be easily seen or obtained for study. Through observation of a skeleton model, students will discover that they have a skeleton inside of their body even though it is difficult for them to see without the aid of scientific equipment. In addition, they will construct a model to help them begin to understand that bones provide structure and support for the human body.

In Investigation Two, students will add to their experience by constructing a model of a pond from start to finish. Students will then test whether a falcon tube cap, acrylic cylinder, and cotton ball will float or sink in the pond. Students will evaluate their results and assign each of the three objects a role in the pond model based upon their ability to float or sink: either a duck that floats on the surface of the pond or a fish that lives under the water of the pond. Their observations will enable them to realize that models are made up of parts and that each part should be represented in the final and complete model. In addition, students should begin to understand that materials used in a model should ideally be chosen because they represent or illustrate properties of the object or part of the object being modeled.

In Investigation Three, students will learn to use symbols to record observations. During this Investigation, students will:

• build a ramp out of a woodblock and two rulers.
• push a car with and without wheels down the ramp.
• push a car with and without wheels up the ramp.
• test a car with and without wheels on a smooth surface to see how far it would move.
• test a car with and without wheels on a rough surface to see how far it would move.
• use arrows to show where and how far the cars moved.
• use straight and wavy lines as symbols for rough and smooth surfaces.