Measurement Lab for Kids

A ruler has two sides. One side shows inches and the other shows centimeters.

• Always start measuring from 0, not from the edge of the ruler
• Line up the left end of the object with the 0 mark
• Read the number where the right end of the object stops
• 1 inch = 2.54 centimeters

Centimeters are smaller than inches, so you need more of them to measure the same object.

Liquid volume is measured in milliliters (mL) or cups. A graduated cylinder has marks on the side to help you read the volume.

• Place the cylinder on a flat surface
• Look at the liquid from the side, at eye level
• Read at the bottom of the curved surface (called the meniscus)
• 1 cup = about 237 mL

Mass tells you how much matter is in an object. Scientists measure mass in grams (g) and kilograms (kg).

• A balance scale compares one object to known weights
• When both sides are level, the object equals the weights
• 1 kilogram = 1,000 grams
• A paper clip is about 1 gram

Different countries use different units. Here are some handy comparisons to remember.

• 1 foot is about 30 cm
• 1 kilogram is about 2.2 pounds
• 1 liter is about 4 cups
• 1 meter is a little longer than 1 yard

When comparing, convert both measurements to the same unit first, then compare the numbers.