E2.1 Explain the relationships between grams and kilograms as metric units of mass, and between litres and millilitres as metric units of capacity, and use benchmarks for these units to estimate mass and capacity.
Activity 1: Conversion Between Metric Units of Capacity
Goal
In this activity, students make conversions between units of capacity using proportional reasoning.
Material
- 250 mL and 1 L measuring cups
- dry filling material (rice, corn grains, beans, etc.)
Instructions
In some situations, it is advantageous to make conversions between units of capacity. For example, in a kitchen, it is often necessary to convert from millilitres to litres or vice versa.
Proportional reasoning is a useful tool for making these conversions.
Give students a 250 ml measuring cup and a 1 L measuring cup. Ask the students to predict how many 250 ml will be needed to fill 1L. Next have them check their prediction using the measuring cups and material. Based on this relationship have students complete the following conversion chart.
| ml | 250 | 500 | 750 | 1000 |
|---|---|---|---|---|
| L |
Ask students to estimate and then find solutions to the following three problems.
- If a 1000 mL pot has a capacity of 1 L, how many times greater is a 22 000 ml pot? Will the capacity of a 22 750 mL pot be closer to a 22 L or a 23L pot?
- A paint container has a capacity of 19 L of paint. Will 18 345 ml paint fit in this container? Explain why or why not.
Source: translated from L’@telier - Ressources pédagogiques en ligne (atelier.on.ca).
Activity 2: Conversion Between Metric Units of Mass
Ask students to find three objects in the classroom.
Invite them to estimate the mass of each by weighing each object in one hand and the weights (grams) in the other hand.
Ask them to weigh the objects using a pan balance to determine the mass in grams of each object. Review their estimates.
Ask them to add up the mass of the three previously selected objects and convert the total from grams to kilograms.