To begin the lesson we review what we have already learned with the customary units of measure. I ask, What country did we say used customary units? Class response: United States. This week, we are studying the metric units. We learned about length, capacity, and weight in the customary units. Now we are doing the same thing with the metric units.
Today's lesson is the metric units of capacity. What does capacity mean? Student response: the amount something can hold. Before we discuss the metric units of capacity, I review the customary units of capacity. What are the customary units of capacity? Student response: pints, quarts, gallons, and cups. I ask the students to put these units in order from least to greatest. Student response: cup, pint, quart, and gallon. (One misconception that the students are having with capacity is thinking that you can only measure liquids in capacity. I make it clear that other things, such as sugar and flour, can be measured in cups, etc.) In this review, we discuss that fact that things can be measured in smaller units, but it would take longer to measure them.
Today we will focus on metric units of capacity. We have two units to discuss today: liter (L) and milliliter (mL). I show the students an eyedropper with water in it to demonstrate the capacity of the milliliter. As we discuss the liter, I hold up a liter measuring cup filled with water. This gave the students a visual of how the two compare. Which is bigger, a milliliter or a liter? Student response: liter. I let the students know that a liter is 1,000 times larger than a milliliter.
I let the students know that they will explore this concept today.
For this activity, I let the students work as pairs to determine the correct metric unit of capacity to use to measure certain items. By doing this, it allows the students to hear their classmates thinking on the skill.
I give each pair a Metric Units of Capacity. Each team is also given a plastic cup, an eyedropper, and a liter cup filled with water. The students must determine the correct metric unit of capacity to use to measure items found in the chart. The students are required to work together on each item. As you hear in the Video - Metric Units of Capacity, the students must use reasoning to find their answers.
As they work, I monitor and assess their progression of understanding through questioning.
1. Is this a large item or a small item?
2. What is the most reasonable unit of capacity to use?
3. Can you use a different unit of capacity? How do you know?
When the students have found the most appropriate metric unit of capacity, they are given a liter cup of water and an eyedropper. The group selects the correct tool to measure the amount of water that a cup can hold. The students work together to try and fill the cup with water by using the tool they selected. (All of the students selected the eyedropper.)
The students really enjoyed using the eyedropper to determine the capacity of a cup. With the liter container filled with water sitting right in front of the students, it gave them a clear understanding of the reason why it is not the most appropriate unit of measure to measure water in a cup.
To close the lesson, I bring the students back together as a whole class. I feel that it is very important to let the students share their answers as a whole class. This gives those students who still do not understand another opportunity to learn it.
I feel that by closing each of my lessons by having students share their work is very important to the success of the lesson. Students need to see good work samples (Student Work - Metric Units of Capacity), as well as work that may have incorrect information. More than one student may have had the same misconception. During the closing of the lesson, all misconceptions that were spotted during the group activity will be addressed whole class.