Students need to learn the skills involved in describing the world around them. Some descriptions can be quantitative such as weight and measurement. Other descriptions are qualitative such as texture, color, and odor. In this exercise students will begin to describe an object quantitatively. They will learn to use a metric ruler to measure certain two-dimensional objects. They will see the difference between seeing something as "big" or "little" and seeing that the object has a definite measurements.

We highly suggest that you use metric rulers, especially for science. The international standard is metric in science, so it is just learning the tools of the trade. You can still use English, but the more you use metric independent of the English system, the children will become familiar with the scale.

Conversion is not necessary if a child has a "feel" for a centimeter, a meter, or a kilometer independent of an inch, a yard stick, or a mile.

PROCEDURE:

1. Inform the students that they will be learning how scientists describe things. Scientists use the same methods you would to describe an object to another person. However, scientists can observe and describe in greater detail because they are trained.
     
2. Review basic descriptive words such as colors, shapes, sizes, textures, and other descriptive terms. Hold up objects like apples, erasers, or pencils, and have the class describe them. Tell them a Martian has arrived from outer space and he does not know what the items look like or feel like. Ask the students how they would describe the object so that the Martian would understand what it is ?
     
3. Pick a student to come to the front of the class. (Be sure to pick a student who is not sensitive.) Ask the students to describe him/her. Try to get them to use words dealing with size. Tell them that the words "big" and "little" sometimes do not give all the information we want. We need to measure them to be accurate. You may want to have the class compare the student with yourself or another student. Ask the question, "How much bigger is one person from the other?"
     
4. How do we measure? Give students a ruler and have them look at centimeters and millimeters.
     
5. Show students different objects and ask them to predict how large they are. At the beginning they will not have a clue. After the students have given their answers, measure and tell the class. After about 5 or 6 of these measurements they may be able to predict a little better. You are increasing their observational skills by giving them knowledge to help them predict more accurately.
     
6. Measure different units in the doorway so the children can begin to estimate how tall a person is when they come through the door. In many areas, stores have the door marked. In case of a robbery, a person would be able to tell how tall the robber was.
     
7. Pass out the worksheet. The worksheet helps students measure two-dimensional objects. Inform the students that they will be measuring in the metric system. It is very easy to measure exactly using the metric system. Model how to measure the first object on the worksheet. Tell them cm = centimeter and mm = millimeter. Ask the students to write the large number first (before the letters cm.) and then count the number of little lines between the big numbers. We call these little lines "ticks". Each tick represents one mm. Ask the students to record their answers in the spaces below the pictures.