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# Estimate Weight in Metric

Estimate, calculate, and compare the metric and U.S. customary weights of favorite everyday objects. Write and erase your predictions on a predict-and-compare table.

• 30 to 60 minutes
• ## Directions

1. Ask students how they describe how heavy something is? As a class, brainstorm different words that describe the weight (mass) of objects. Review the common U.S. customary and metric units for measuring weight. U.S. customary weight units include the pound and ounce: 1 pound (lb) = 16 ounces (oz) Metric weight units are based on the gram (g): 1 gram (g) = 1000 milligrams (mg), 1000 grams (g) = 1 kilogram (kg)
2. Students explore how heavy each unit feels by holding weights or objects clearly labeled with their weights. Compare metric and U.S. customary weight units by holding them and feeling their heaviness. How does a pound compare to a gram? How does a kilogram compare to an ounce?
3. One way to explore the different units of measurement is for students to create a predict-and-compare table in small groups. Start with five or six everyday objects such as a crayon, lunch box, math book, snack bar, box of markers, and tissue box. Draw a picture of one of your objects using Crayola Erasable Colored Pencils on construction paper.
4. Weigh the item on a scale or balance (using weights) to find its metric weight. Beside its picture, write the metric weight. Next estimate what the weight will be in U.S. customary units. Students write their predictions.
5. Now weigh the object to find out the actual U.S. customary weight. Was their prediction close? How does it compare to the number of metric units? Erase the estimate and replace it with the actual U.S. customary weight. Repeat steps 5 and 6 with two or three more objects.
6. Now repeat steps 5 and 6 with the rest of the objects, but this time measure the U.S. customary weight first, and estimate what the metric weight measurement might be.
• ## Standards

LA: Engage effectively in a range of collaborative discussions with diverse partners on grade level topics, texts, and issues, building on others' ideas and expressing one's own clearly.

LA: Acquire and use accurately grade-appropriate general academic and domain-specific words and phrases, including those that signal contrast, addition, and other logical relationships.

LA: Produce clear and coherent writing in which the development and organization are appropriate to task, purpose, and audience.

MATH: Convert like measurement units within a given measurement system.

VA: Intentionally take advantage of the qualities and characteristics of art media, techniques, and processes to enhance communication of experiences and ideas.

VA: Select and use the qualities of structures and functions of art to improve communication of ideas.

Possible classroom resources include: Let's Visit Canada: The Metric System (Powermath) by Joanne Mattern; Millions to Measure by David M. Schwartz; Natural Wonders of the World: Converting Distance Measurements to Metric Units (Math for the Real World: Proficiency Plus) by Kerri O'Donnell

Organize students into small groups to investigate metric measurement in their classroom. Provide students with a list of items in or near the classroom to measure such as one window, the height and width of the doorway, a student desk, an unused pencil, the size of a sheet of construction paper, etc.

Encourage students to widen their exposure to the Metric System and explore metric weight (mass) and metric volume. Students complete and organize their research into an electronic formation for sharing with classmates.

Invite students to find objects that weigh exactly 1 gram, 1 kilogram, 1 ounce, and 1 pound. Memorize which object corresponds to which unit. Students can use this newly acquired information to estimate the weights of other objects. For example, if 2 small paper clips weigh about 1 gram, what would a paper towel weigh in comparison?

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