Measurement progression, 4th step
The purpose of the activity
In this activity, the learners develop an understanding of the size of 1 litre and 1/2 litre. They learn to express these amounts in millilitres. They develop their skill at estimating the volume of containers in litres and millilitres by establishing personal benchmarks.
The teaching points
- The learners will develop an understanding of the size of 1 litre and 1/2 litre.
- 1 litre = 1,000 millilitres and 1/2 litre = 500 millilitres.
- The symbols for litre are l or L, and the symbols for millilitre are ml or mL.
Note: The metric system symbols do not use ‘s’ for the plural: 50 millilitres is written as 50 ml or mL not mls or mLs.
- The learners will understand the use of benchmarks (for example, a water bottle and a beer can where the volume is known and remembered) to estimate volumes in litres and millilitres.
- The learners will be able to read scales for measuring volume.
- Discuss with the learners the fact that the terms volume and capacity are both used to describe the amount of space a solid occupies. They are sometimes distinguished, with capacity being used for how much a container can hold (measured in litres or its derived units) and volume being how much space an object displaces (measured in cubic metres or its derived units.)
- Each learner to find and bring one empty litre container, for example water bottle or milk container.
- Containers (smaller than 1 litre) with the volume written on them, such as soft drink or beer cans.
- Containers larger than 1 litre such as a bucket, electric jug.
- A variety of empty containers, some smaller and some larger than 1 litre, without the volume written on them, such as jars and glasses.
- Sand or water for measuring volume.
- Measuring cup, jug and/or cylinder marked in millilitres.
The guided teaching and learning sequence
1. Ask the learners to think about situations where they might need to have an understanding of the size of litres and millilitres. Possible examples are judging whether you have sufficient oil for an oil change, whether the amount of liquid in a holding tank is small enough to be able to be released into the drain, catering, giving medicines, etc.
2. Give each group of learners five or six containers and ask them to decide which are smaller and which are larger than 1 litre. Encourage them to use the litre container they have brought to make the decisions.
3. If the learners are unsure whether a container holds more or less than 1 litre, ask them to find out by filling the container with sand or water and tipping the contents into a known litre container – be prepared for spills!
4. Discuss using their litre container as a benchmark for estimating volumes in the future.
“Estimate how many litres in a standard bucket, in an electric jug, in a sink.”
5. Explore the connection between litres and millilitres by asking:
“What does milli mean?” (one thousandth (1/1000) part of)
“How many millilitres in 1 litre, 2 litres, 1/2 litre, 1/4 litre?” (1,000 mL, 2,000 mL, 500 mL, 250 mL)
“How many litres in 3,000 mL, 1,500 mL?” (3 L, 11/2 L)
Using containers that are smaller than 1 litre, ask the learners to decide which are smaller and which are larger than 1/2 litre/500 mL. Get them to check their decisions by filling the container with sand or water and using the measuring cup, jug and/or cylinder marked in millilitres.
6. Ask the learners to try to find out the volume. Be familiar with the scale on the device so you can show the learners how to read an accurate measurement.
7. Share all results with the whole group so the learners see and are told the volume of a large range of containers.
8. Show the learners containers for which the volume is given and read out the volume. Demonstrate how the learners could use one of these as a benchmark for estimating millilitre volumes. For example, if you know the beer can holds 330 mL, estimate the volume of the wine bottle.
9. Using their litre and millilitre benchmarks, ask the learners to estimate the volume of containers not already measured. Possibilities include coffee cups, glasses, a wine bottle, a large juice container, a medicine cup, a teaspoon. Ask the learners to work in groups and share and justify their decisions.
Ask the learners to estimate and read/measure the volume of containers before the next session and to bring one to share with the group at the next session.
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