Comparing the Volume of Containers Using Rice
- Provide opportunities for practice with direct and indirect comparison
- Start with comparing only one attribute
- Direct comparison - physically arrange objects so that key attributes are fairly aligned
- Model language to use to describe attributes
- Draw students' attention to objects attributes
- Modeling and using math language
- Extending mathematical thinking
What to Look for in This Clip:
Teachers can support students' early measurement skills by giving them opportunities to describe and compare the mathematical attributes (e.g., length, weight, area) of objects and people.
In this activity, the teacher provided an opportunity for students to indirectly compare the volume of three different containers by measuring how much rice each could hold. As the teacher and students discuss their results, the teacher draws attention to the containers' different attributes and models language to describe those attributes.
As the class is looking at their chart to see how many scoops of rice each container held, the teacher models language used to describe attributes by using the word biggest, commenting, "And then this one's the biggest." She also connects the word to its meaning by placing the container with the largest volume while saying, "the most".
The teacher also draws students' attention to a different attribute of the containers, their height, by saying, "You guys originally thought that this one, A, would hold the most. Remember, because it was so tall? But did it hold the most?" The students respond no, reinforcing the difference between the container's height and its volume. The teacher extends their mathematical thinking by summarizing this key idea, "Just because [A]'s tall, doesn't mean it has the greatest volume. Because [C] is also wide, so it can hold more rice, it has a greater volume than this one (A)."