# Capacity

**Strand:** Shape and Space (Measurement)

**Outcome:** 5

## Step 3: Plan for Instruction

### Guiding Questions

- What learning opportunities and experiences should I provide to promote learning of the outcomes and permit students to demonstrate their learning?
- What teaching strategies and resources should I use?
- How will I meet the diverse learning needs of my students?

### A. Assessing Prior Knowledge and Skills

Before introducing new material, consider ways to assess and build on students’ knowledge and skills related to capacity.

Ways to Assess and Build on Prior Knowledge

### B. Choosing Instructional Strategies

Consider the following general strategies for teaching capacity (Van de Walle 2001):

- Access prior knowledge on using perimeter, area and volume in the real world.
- Introduce capacity by drawing on familiar and accessible contexts to illustrate uses of capacity (NCTM 2000).
- Review the process used in developing understanding of perimeter, area and volume and use a similar process in developing understanding of capacity, stressing that the attribute changes but the process is similar:
- Explain that the attribute to be measured is capacity.
- Check for conservation of capacity; e.g., pour liquid to the same level in two identical containers and then pour the liquid from one of the containers into a taller or shorter container and compare the amount of liquid.
- Always estimate prior to comparing or measuring capacity.
- Make direct comparisons; e.g., compare the capacity of two containers by pouring the content of one container into the other container.
- Estimate the capacity of a container using nonstandard units of measure; e.g., plastic caps or liquid medicine cups. Use various techniques for estimating capacity:
- Referents—use a referent for the single unit of measure and iterate this unit mentally to obtain the estimate; e.g., use a handful as a referent for about 25 mL.
- Chunking—estimate the capacity of a smaller portion of a container initially and use this estimate to estimate the entire capacity of the container; e.g., estimate the capacity of a smaller section of a container and then multiply that answer by the number of these sections in the entire container.
- Iteration—iterate a unit mentally or physically; e.g., use a single unit repeatedly to visually estimate the capacity of a container (Van de Walle and Lovin 2006).

- Have the students share their strategies for estimating capacity.
- Accept a range of estimates—within 30% of the actual measure is reasonable (Van de Walle and Lovin 2006, p. 279).
- Encourage the students to measure the capacity after each estimate so that they develop a better sense of capacity.
- Use nonstandard units of measure that have the same attribute as the item being measured; e.g., use plastic caps or liquid medicine cups to measure capacity of a container.
- Make indirect comparisons using a nonstandard unit of measure that has the same attribute as the item being measured; e.g., use plastic caps or liquid medicine cups to measure the capacities of containers for the purpose of comparison.
- Measure the capacity of a container using larger then smaller nonstandard units of measure to establish that the smaller the unit of measure, the more you need to measure the capacity of a given container; e.g., more small plastic capfuls are needed than larger plastic capfuls to measure the capacity of a given container.
- Explain the need to use standard units to measure capacity to facilitate communicating the measurements globally.
- Measure the capacity of a given container using an appropriate instrument with standard units of measure; e.g., use a graduated beaker marked in millilitres to measure the capacity of a container.

### C. Choosing Learning Activities

Learning Activities are examples of activities that could be used to develop student understanding of the concepts identified in Step 1.