Measure Length, Mass, and Capacity
Lesson preview: the Mini Lesson and Vocabulary are open to everyone. Guided practice, exercises, the parent checklist and the printable PDF worksheet come with full access (free 7-day trial or membership).
What you will learn
- 1Name the right tool and a US customary and metric unit for length, mass, and capacity
- 2Read a measurement from a ruler, scale, or measuring cup in both unit systems
- 3Choose the most sensible US customary or metric unit when estimating a real-life measurement
Mini Lesson
Measurement lets us describe the world in numbers. We measure three key attributes: length (how long), mass (how heavy), and capacity (how much a container holds). In the US we use two systems side by side: customary units (inches, pounds, cups) and metric units (centimeters, grams, liters). Both are correct — pick the unit that fits the size of the object.
Length
- Use a ruler for short lengths — inches (in) on one side, centimeters (cm) on the other.
- Use a tape measure for longer lengths — feet (ft) and yards (yd), or meters (m).
- Long distances: miles (mi) for US road signs; kilometers (km) for science and most countries.
- Anchors: a pencil is about 6 in or 15 cm. A door is about 7 ft or 2 m. Four laps of a running track are about 1 mi or 1.6 km.
Mass
- Use a kitchen scale or balance scale to find mass (or weight).
- Small objects: ounces (oz) or grams (g). Larger objects: pounds (lb) or kilograms (kg).
- Anchors: an apple is about 6 oz or 170 g. A bag of sugar is about 5 lb or 2.3 kg. 1 lb ≈ 454 g; 1 kg ≈ 2.2 lb.
Capacity
- Capacity is how much liquid a container can hold.
- Use a measuring cup (cups, pints, quarts, gallons; 4 quarts = 1 gallon) or a graduated cylinder (milliliters, liters).
- Anchors: a drinking glass is about 1 cup or 240 mL. A milk jug holds 1 gallon or about 3.8 L. A teaspoon holds 5 mL.
Words to know
Length
How long something is
e.g. A pencil is about 6 in or 15 cm long.
Mass
How heavy something is (in everyday talk, also called weight)
e.g. An apple has a mass of about 6 oz or 170 g.
Capacity
How much liquid a container can hold
e.g. A milk jug has a capacity of 1 gal or about 3.8 L.
US customary
The US system of units: inches, feet, pounds, cups, gallons
e.g. In the US, recipes often use cups and ounces.
Metric
The science system of units: centimeters, meters, grams, kilograms, liters
e.g. Scientists worldwide use the metric system.
Inch
A US customary unit of length; about the width of an adult thumb (≈ 2.5 cm)
e.g. A new crayon is about 3.5 in long.
Centimeter
A small metric unit of length, about as wide as a fingernail
e.g. A pencil is about 15 centimeters long.
Pound
A US customary unit of mass; 1 lb ≈ 454 g; 1 kg ≈ 2.2 lb
e.g. A bag of sugar is about 5 lb.
Kilogram
A metric unit of mass equal to 1,000 grams
e.g. A bag of sugar is about 2.3 kg.
Gallon
A US customary unit of capacity; 1 gal ≈ 3.8 L
e.g. A milk jug holds 1 gallon.
Liter
A metric unit of capacity equal to 1,000 milliliters
e.g. A water bottle holds about 1 liter.
Match the unit to the size: tiny → in / cm / oz / g / mL; medium → ft / m / lb / kg / cup; big → mi / km / gal / L.
Unlock the full HSEA system for 7 days.
Add your first kid profile and your 7 days start: every lesson in every grade, saved progress for each child. Nothing to set up, no card required, nothing to cancel.
- ✓ All 1,880 lessons, Grades 1–6, every subject
- ✓ Profiles + saved progress for every kid
- ✓ Printable lessons with answer key