1.5 class periods

[1-3] The Metric System

The purpose of this section is to explain the basic units of measurements in the metric system. The metric system is a universal system of measurement and allows scientists and people from all over the world to compare and analyze data. Students will learn that the basic unit of metric length is the meter (m); of liquid volume is the liter (L); of solid volume is the cubic centimeter (cm³ or cc); of mass is the kilogram (kg); of density is grams per milliliter (g/mL); of metric temperature is Celsius degrees (¥ C).

Students will also learn the skill of dimensional analysis, or converting from one metric unit to another.

The themes that can be focused on in this section are scale and structure and stability.

Scale and structure: Point out that the metric system is a decimal system in which units increase or decrease by powers of 10.

Stability: Sometimes scientists must compare substances based on their mass and volume. The relationship between mass and volume is called density, and the density of a substance is constant.

Performance Objectives 1-3

1. Explain the importance of a universal language of measurement.
2. Identify the metric units used in scientific measurements.
3. Use dimensional analysis to convert one metric unit to another.

Science Terms 1-3

Metric system, p.20

Meter, p.20

Centimeter, p.21

Millimeter, p.21

Kilometer, p.21

Liter, p. 21

Milliliter, p.21

Cubic centimeter, p.21

Kilogram, p.22

Gram, p.22

Milligram, p.22

Density, p.22

Celsius, p.23

Dimensional analysis, p.23

Conversion factor, p.23

Have students study Figure 1-15, p.20 for test.

• How many kilograms are equal to 1357 grams? (1357 g X 1 kg/1000 g = 1.357 kg.)
• How many kilograms are equal to 791 grams? (791 g X 1 kg/1000g = 0.791 kg.)
• How many grams are equal to 3.184 kilograms? (3.184 kg X 1000 g/1 kg = 3184 g.)
• How many grams are equal to 0.31 kilograms? (0.31 kg X 1000 g/1 kg = 310 g.)

• What are the basic units of length, volume, mass, and temperature in the metric system?
• What metric unit of length would be appropriate for expressing the distance from Earth to the sun? Why?
• To measure the size of atoms, scientists use the unit called the Angstrom. An Angstrom is one ten-billionth of a meter. How many Angstroms are in a meter? (10 billion Angstroms in a meter.)
• Without placing an object in water, how can you determine if it will float?