Provide students with index cards and markers. Have them brainstorm different measures used in the metric system and record them on index cards.
In pairs, have the students organize the index cards into categories of weight, length, and volume. Ask the students to rank each unit within the category according to size (smallest to largest).
A sample chart appears below.
| Length |
Mass |
Volume |
| millimeter | milligram | milliliter |
centimeter | gram | liter |
meter | kilogram | |
kilometer |   | |
Next, have the students generate a list of items measured with each unit. Place each item on a separate index card and distribute the cards among the class.
A sample list is shown below.
| Length |
Mass |
Volume |
millimeter insect lengths | milligram medicines | milliliter medicine dosage |
centimeter length of paper | gram food | liter milk |
meter length of a hallway | kilogram mass of humans | |
kilometer distance between cities |   | |
After the students are familiar with the different sizes of the metric units, show them a conversion table. Refer to the Metric Equivalents lesson plan on the Educator’s Reference Desk Web site for an explanation of the conversion method by multiplying and dividing by powers of ten.
Distribute the Metric Conversions activity sheet to the students to work on individually or in pairs.