Ounces, Pounds, and Tons
Background Information & Activities

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In early elementary education, children explore the units, systems, and processes of measurement. We recommend giving your children plenty of hands-on practice to help them recognize the attributes of length, weight, volume, area, and time. Hands-on activities will also help them recognize and select the appropriate unit and tool for measurement and build and improve their measuring skills. This movie explores weight through ounces, pounds, and tons. Measurements within the metric system will be addressed in separate movies.

Review with your children that weight is how heavy something is. Weight is a measurement of the gravitational force acting on an object. Mass, however, is a measurement of the quantity of matter in an object. Therefore, the weight of an object changes based on gravitational pull, while its mass remains the same. An object on the Moon will weigh less than the same object on Earth because there is less gravitational pull. However, its mass on the Moon will be the same as on Earth. The distinction between weight and mass is important in the physical sciences and laying the basic groundwork for this concept can offer an opportunity to make a connection to science.

Children can estimate the weight of different objects to find ones that are heavier, lighter, or about the same weight. Remind your children that when they estimate, they make a good guess. They can also use a balance scale to compare weights of objects. You may wish to model key phrases such as “heavier than” and “lighter than” or “weighs more” and “weighs less.”

It takes time and experience for young students to understand the need for standard units of measurement. A good way to introduce students to the need for standard units is through exploration of balance scales without unit measurements. Ask your class to look at and feel objects and predict which is heavier or lighter. Ask them how they could prove which is heavier or lighter. Then, compare the objects on opposite pans on a balance scale. Give your students many opportunities to predict which objects are heavier and lighter and then check their predictions on balance scales themselves. Then ask students to find a way to find objects that weigh the exact same amount. Finally, students can use a single unit of weight to compare the weights of various objects to prove that they weigh the same amount. For example, you might ask the class to use pennies or cubes to find the “exact” weight of classroom objects. After you have established the need for a common unit of measurement of weight, you can begin to discuss the standard measures of ounces, pounds, and tons.

In the United States and a few other countries, we often use ounces, pounds, and tons to measure weight. Show your class a scale with ounces and pounds and have your children look at the numbers and how they are organized. They may have difficulty determining the difference between the ounce and pound marks, so be sure to give the class time to explore the scales up close. Show an object that weighs about an ounce, such as a slice of bread. Have your children find other objects that weigh about an ounce. Remind them that they should use ounces to measure light objects. The abbreviation for ounce is “oz”. They should use pounds to measure heavier objects. Show an object that weighs about a pound, such as a loaf of bread or a small melon. There are 16 ounces in 1 pound. The abbreviation for pound is “lb” and the abbreviation for pounds is “lbs.” Weigh different objects together on a scale and have your children practice reading the measurements.

Explain to your children that people can use tons to measure very heavy objects. There are 2,000 pounds in a ton. A small car weighs about 1 ton. The largest mammal is the blue whale, which can weigh about 150 tons, or about 300,000 pounds. Compare that weight to an elephant’s, which is only about 15,000 pounds.

When children learn about measurement, they develop the fundamental concepts and skills they need to explore the world around them. Measurement tools help them understand the need for standardized units. What if everyone used rulers with different units? What might happen? Math and measurement pose fascinating questions about our world and provides answers as well.

See more lesson plans and resources: BrainPOP Educators.

Ounces, Pounds, and Tons Teacher Activities

© 1999-2012 BrainPOP. All rights reserved.

Nonstandard Units

Why do people use the same units to measure things? If possible, give small groups or pairs a balance scale and have them place a wooden block on one side. Then have groups use different weights on the opposite side of the scale to balance the block. For example, one group might use pennies, while another group might use crayons. Make sure groups use the same kind of weight with their scale. In other words, a single group should not use pennies and crayons to balance the block. After the activity, have students discuss why it is important to have standard units of measurement.

Build a Scale

Have your students work in pairs to build crude balance scales using a coat hanger, paper clips, and paper cups. They can use the paper clip to attach the cups to either ends, and hang the scales from hooks or strings, or on their finger. Have students put objects into the cups to compare their weight. They can also pennies or other classroom objects to “measure” weights of different objects. As students compare their results from their balance scales, ask the class to decide if they are accurate tools for measurement. Why or why not?

Lighter or Heavier

Have a student volunteer present an object to the class. Then have other students find examples of objects that are lighter or heavier than the object. Students can use a scale to measure the exact weight and compare. If possible they can subtract to find the difference in weight. Then challenge students to find objects that weigh about the same.

Large and in Charge

Research the weights of different large objects or animals together, such as a car, an elephant, or a blue whale. Have students weigh themselves and then as a class activity, add the weights together using a calculator. How many students does it take to add up to the weight of a single elephant?

Ounces, Pounds, and Tons Family Activities

© 1999-2012 BrainPOP. All rights reserved.

Weight Change

Have your child weigh himself or herself on a scale in pounds and ounces. Then have him or her record the weight on a chart, using proper abbreviations. Keep a record of how your child grows and help him or her subtract to find the difference. Together, you may want to look back at your child’s baby book or health records to find out how much he or she weighed at younger ages, too. You can also use this opportunity to display the data in a line graph. You may also wish to do this activity with pets.

Grocery Store Challenge

Take your child to a grocery store and explore weights of different fruits and vegetables. Ask your child to estimate the weight of one apple or pineapple and then use the scale to find the exact weight. Ask questions to your child and have him or her explore to find the answer. How many apples do you need to reach one pound? Which is heavier, an eggplant or a cauliflower? Make sure your child keeps a record of his or her findings.