Unit 2, Lesson 14
Anchoring Units of Measurement
Accelerated 6
Preparation
Lesson Narrative
This lesson activates and builds on students’ prior knowledge of units of measurement. It anchors students’ perception of standard units of length, volume, weight, and mass with familiar objects serving as benchmarks. This work prepares students to reason about ratios and rates in the context of measurement and to perform unit conversions.
The lesson opens with an invitation to estimate the volume of salt in a salt shaker. It is followed by two optional activities that reinforce standards from earlier grades. The first optional activity, “What Do They Measure?”, prompts students to classify standard units based on what they measure. The second optional activity, “Cutting Strings,” grounds students’ awareness of standard units of length in concrete objects (a collection of strings).
The main activity is a Card Sort in which students match images of common objects with their closest unit of length, volume, mass, or weight. Relating standard units with perceivable objects (such as the length of a baseball bat) or experiences (such as the distance walked in 10 minutes) strengthens students’ grasp of the units and prompts them to reason abstractly and quantitatively (MP2).
A note about weight and mass:
In earlier grades, students learned that “weight” describes how heavy an object is and can be measured in grams and kilograms. Because this understanding is consistent with everyday usage and because students may not have learned the distinction between mass and weight, these materials continue to use grams and kilograms as units for weight. For students who can distinguish mass and weight, consider clarifying that weight can be expressed in grams or kilograms assuming that it is measured at sea level on Earth.
If students wonder about the meaning of “mass,” consider explaining that it measures how much matter is in an object and is usually measured in grams or kilograms. Clarify that these concepts will be studied in a future science course.
This lesson and the following lesson are both optional in this course. Choose one of these lessons to activate students’ background knowledge about units of measurement before proceeding with the lesson on converting units.
- Compare (orally) the relative size of different units of measure for one attribute, that is, length, volume, and weight or mass.
- Comprehend the approximate size of 1 “inch,” “foot,” “yard,” “mile,” “millimeter,” “centimeter,” “meter,” “kilometer,” “ounce,” “pound,” “ton,” “gram,” “kilogram,” “cup,” “quart,” “gallon,” “milliliter,” and “liter.”
- Identify which unit is closest to the length, volume, weight, or mass of a given object, and explain (orally) the reasoning.
Let’s see how big different things are.
Required Materials
Required Preparation
For each group of 2 students, prepare a pair of scissors and more string than necessary for their assigned unit of length. To distribute the string without wasting too much or giving away the actual lengths, consider dividing one ball of string ahead of time into equal spools, enough for every group to get one. The spools can then be reused class after class. Rotate the spools between groups assigned shorter and longer lengths, so that one spool does not run out long before the others.
Only one of each of the ruler, meter stick, and yardstick is needed for demonstration purposes.
Prepare 1 copy of the blackline master for each group of 4–6 students. If possible, copy each complete set of cards on a different color of paper, so that a stray card can quickly be put back.
Prepare several examples of real objects depicted on the cards so that students can see them at actual size, especially any objects that may be unfamiliar to students. A real quart-sized bottle is an especially crucial example to have.