Dear Family, your Operation Maths guide to Capacity

Dear Family, your Operation Maths guide to Capacity

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Dear Family, listed below are some practical suggestions as to how you might support your children’s understanding of the maths topic of capacity. Also below, are a series of links to digital resources that will help both the children, and you, learn more about capacity. The digital resources are organised according to approximate class level.

Junior Infants to Second Class
You can also find class specific tips at the back of your child’s Operation Maths At Home book, for infants to second class, and in the Operation Maths Dear Family letters for third to sixth class.

Practical Suggestions for all Children

  • Where possible allow your children to have opportunities for “water play”; this can be during bath time, playing in the sink when the washing up is done, having tea-time with a play tea-set, playing outside with a basin of water and containers, etc. Sand play, if available, should also be encouraged as children explore with “pouring” sand from one container to another.
  • In school, the children are enabled to compare, estimate and measure capacity. You can reinforce this at home by asking the children to use their visual sense of capacity to compare and estimate which bottles, containers etc., hold more or hold less. Collect a selection of various types of bottles and containers and, if possible, remove any telling labels. Ask the children to line the containers up in order, starting with the one that they think holds the least. Fill this one with water, and then pour this water into the second container.
    • Does all the water fit? If no, then the first container holds more than the second container.
    • If yes, does the water from the first container fill the second container to the same level? Then they both hold the same amount.
    • Or is there space left at the top of the second container? Then it must hold more than the first container.
  • When estimating capacity, do the children realise that height and/or shape is not always indicative of capacity i.e. a taller but skinnier container may contain less than, or the same as, a shorter container.
  • When investigating capacity, try to conserve water; have a large basin handy, or do the water-pouring over a closed sink or bath so that the water can be reused. Why not even investigate the capacity of various containers as part of water play in the bath or sink?
  • Draw the children’s attention to capacity labels on bottles and containers, especially l for litres and ml for millilitres. Even children who may not yet know that there are 1,000ml in a litre, can examine labels and can use their number knowledge to identify the one which holds the most/least. If the item does not have a capacity label, does it have a label for a different unit of measurement and why is this? (e.g. perhaps g or kg for weight).
  • Is it good value? Keep a close eye on the capacity of various items when shopping (whether it be in the shops or online): while you’d expect that a 3l bottle of drink would be twice the price, or slightly less than twice the price, of a 1.5l bottle of the same drink, you would not expect it to be dearer – yet that can sometimes be the case! So involve the children in checking the capacity of items to make sure that you’re getting the best value for your money!
  • Find the items around your home that measure capacity (these are often called measuring instruments): kettles; liquid detergent caps and dispensers; medicine cups, spoons and syringes; buckets and basins; measuring jugs. Look carefully at the measuring scale, marked usually along the side, and get the children to try out these measuring instruments for themselves.
  • Involve your child in measuring capacity when cooking and baking. If using recipes, ask the children to calculate how much of each liquid ingredient would be required to make half, double, etc., of the amount/dish.
  • Enlist the help of older siblings if available. As they explain and support the younger members of the family, they will also be developing and consolidating their own knowledge and skills, especially communicating mathematically.
  • Draw the children’s attention to any other situation where capacity needs to be considered eg water conservation around the home, how much water we should drink daily, putting liquid detergent in the washing machine, the capacity of the household bins, the amount of rain forecast, recommended dosage for various medicines, buying enough paint for a particular room, purchasing fuel (eg petrol, diesel, home-heating oil), etc.

Digital Resources for Infants

NUMBERJACKS | The Container Drainer | S1E20 - YouTubeNumber Jacks: The Container Drainer



Lemonade Lessons | Videos | Kids | PeepMaking lemonade: A video showing how some children used capacity as they made lemonade


Comparing Volume (Part 1) - YouTube

Full or Empty: A lesson from Matholia focusing on full and empty


Comparing Volume - YouTubeComparing volume: A lesson from Matholia which focuses on language such as greater than, less than, highest, lowest etc


Kindergarten: Which Container Holds More? - YouTube

Holds more or less? Video lesson



IXL | Maths and English Practice

Holds more or less: a selection of games from You can do a number of free quizzes each day without having a subscription.

Digital Resources for First and Second Classes

Describing Volume - YouTubeHalf full: video from Matholia showing how to describe capacity using “half full”.


Measuring Volume in Litres on VimeoMeasuring in litres: video from Matholia showing how to read the scale on a large container.


ictgames || html5 Home PageCapacity Countdown: Read the level of liquid on the scale and type in the capacity. Recommendation: Stick to litre and half litre option.


IXL | Maths and English PracticeHolds more or less: a selection of games from You can do a number of free quizzes each day without having a subscription.

Digital Resources for Third to Sixth Classes

Measurement IndexMetric Volume (capacity): Background information on volume (capacity) and litres and millilitres as the main metric units. At the end of the page there is a link to an activity, explaining how you could do some capacity activities at home.


Measuring: Capacity - BBC TeachCapacity: Lots of useful information about capacity from BBC Skillswise, including a video highlighting capacity in the real world.

Beginner m Measuring capacity and reading scales converted - YouTubeUsing measuring instruments: a guide to understanding the scales on measuring jugs and using them correctly and accurately.

Converting Millilitres to Litres and Millilitres - YouTubeConverting millilitres to litres and millilitres: A video lesson from Matholia.


ictgames || html5 Home PageCapacity Countdown: Read the level of liquid on the scale and type in the capacity. Recommendation: work through the given options in order.


Topmarks on Twitter: "In our Coconut Ordering game you can compare ...

Coconut Ordering Game: Select Capacity to order amounts of l and ml


Reading Scales - TransumReading Scales: An activity which checks your ability to read scales in various intervals.


BBC NEWS | UK | Q&A: Water meters and youWater Calculator: this resource helps you calculate the amount of water used in your household. (Not tablet friendly – requires Adobe Flash Player).


Math is Fun

The Jugs Puzzle: You have 2 jugs of different sizes & an unlimited supply of water. Can you measure the exact amount of water needed? Has six different levels.


IXL | Maths and English Practice

Metric Measures of Volume (capacity): (ie litres and ml) a selection of games from You can do a number of free quizzes each day without having a subscription.



OdlumsOdlum’s Baking with Kids: What better way to develop and perfect your measuring skills! 


Microsoft Educator Network Ireland – TeachNet Blog › ...

Comparing and converting metric units: Practice games incorporating metric units of weight, capacity and length.


Capacity Quiz: (for 6th class) Multiple choice quiz.