Dear Family, your Operation Maths guide to Capacity

Dear Family, below is a brief guide to understanding the topic of capacity, as well as some practical suggestions as to how you might support your children’s understanding at home. 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 & Senior Infants
• First and Second classes
• Third to Sixth classes

Understanding Capacity

Capacity is the amount that a container, or something, can hold. Very closely related to this is volume, the amount of 3-D space that something takes up. And while both capacity and volume can be used to measure and describe the same objects/substances, there is a distinct difference. For example, the capacity of a empty plastic bottle may be 1 litre, but the volume of liquid it contains will be 0 cm³ (cubic centimetres). The same bottle, if full of water, will still have a capacity of 1 litre, but now, the volume of water contained within is 1 litre or 1,000 cm³.

Like length and weight, capacity has been traditionally measured using two separate systems: imperial units/US customary units (pints, gallons etc) and metric measures (millilitres, litres etc). In Ireland, the changeover to all metric measures began in the early 1970s and was completed in 2005 (although alcohol sold on draught is still sold by the pint ). Therefore, only metric measures are taught in Irish schools.

In school, the children are enabled to compare, estimate and measure capacity. In the infants classes, the children work with non-standard units (e.g. what is the capacity of the bottle in cups?) and then they are gradually introduced to the standard metric units of capacity i.e. litre (first class) and millilitre (third class). Children in the older classes will also be introduced to, and work with, more complex concepts related to capacity, such as calculating the volume of objects and converting from one unit of measurement to another (eg millilitres to litres).

Do you know how the metric system came into being? It has an interesting history! Watch this video and/or read this article. For more background info on capacity/volume you can read this post from Maths is Fun.

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. Read more about sand and water play here.
• 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 purchasing the item(s) that offers 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

Number Jacks: The Container Drainer

Making lemonade: A video from Peep and the big Wide World, showing how some children used capacity as they made lemonade

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

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

Full and Empty with Grover: The Sesame Street favourites explore capacity. Other relevant clips include Elmo & Zoe Full and Empty, Kermit explains More and Less and The Two Headed Monster More and Less Milk

Happy Numbers Kindergarten: Work through the capacity activities in Module 3, Topic D. 

Splash Learn: Compare capacity

I know it – Kindergarten: Scroll down to Measurement and select the holds more or less activities. 

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

Math Games: Choose the Holds more or Less practice games from Junior and Senior Infants

Digital Resources for First and Second Classes

Half full: video from Matholia showing how to describe capacity using “half full”.

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

Mass: A series of video lessons from White Rose Maths, including, for Year 1,  Introduce capacity and volume and Measure capacity; for Year 2, Compare volume, Measure volume in millilitres, Measure volume in litres.

Capacity Countdown: Read the level of liquid on the scale and type in the capacity. Recommendation: Stick to litre and half litre option.

I know it – First Grade: Scroll down to Measurement and select the holds more or less activities. There are similar activities in Second Grade 

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

Math Games: Choose the Holds more or Less practice games from first and second class

Digital Resources for Third to Sixth Classes

Metric 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.

Matholia – Volume: A number of video lessons on volume (capacity) that include Converting Litres and Millilitres to Millilitres, Converting Millilitres to Litres and Millilitres, Converting Litres to Millilitres, Addition, Subtraction, Multiplication and Division of Volume, Volume of a Liquid and Volume of Cubes and Cuboids

Capacity: A series of video lessons from White Rose Maths, including, for Year 3,  Measure capacity, Compare capacity, Add and subtract capacity; for Year 5, Metric units; for Year 6, Metric Measures, Convert metric measures, Calculate with metric measures, What is volume, Counting cubes, Volume of a cuboid

Khan Academy – Mass and Volume (Third Grade): Watch the videos and then answer the practice questions. Afterwards, for something more challenging,  look at the Fourth Grade activities on Estimating Volume and/or Converting Units of Volume. Or even the Fifth Grade activities on Metric Units of Volume. You can also register for a free Khan Academy account to record your progress and explore other topics/grades.  

Happy Numbers Third Grade: Pupils can do the weight and capacity activities in Module 2, Topic A.  

Mashup Math – Volume: Video lessons that show how to Find the Volume of a Rectangular Prism and Finding the Volume of a Right Rectangular Prism Practice Problem

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

Using measuring instruments: a guide to understanding the scales on measuring jugs and using them correctly and accurately.

Capacity Countdown: Read the level of liquid on the scale and type in the capacity. Recommendation: work through the given options in order.

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

Splash Learn – Measurement Games: These games cover how to Estimate Metric Units of Weight and Capacity, Compare Metric Units, Convert Metric Units, Convert Metric Units (Decimal Conversions)

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

I know it – Third Grade: Scroll down to Measurement (Metric) and select the volume activities. There are similar activities in Fourth Grade and Fifth Grade.

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.

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

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

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

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

Dear Family, your Operation Maths guide to Weight

Dear Family, below is a brief guide to understanding the topic of weight, as well as some practical suggestions as to how you might support your children’s understanding at home. Also below, are a series of links to digital resources that will help both the children, and you, learn more about weight. The digital resources are organised according to approximate class level:

• Junior & Senior Infants
• First and Second classes
• Third to Sixth classes

Understanding Weight

The measure of how heavy something is, is often referred to as its weight. But the more correct term for this is mass. Mass is the quantity of matter in an object and doesn’t change but the weight of an object changes according to gravity. In space, a person is weightless; their weight on the moon would be approximately 1/6 of their weight on earth, but their mass would be the same in any of these situations and doesn’t change. That said, weight is the term used most often (even if it is less correct) and as such is the main term used in the Maths Primary School Curriculum in Ireland.

Weight and mass are measured using scales. Like length and capacity, weight/mass has been traditionally measured using two separate systems: imperial units/US customary units (ounces, pounds, stone, etc) and metric measures (grams, kilograms, tonnes etc). In Ireland, the changeover to all metric measures began in the early 1970s and was completed in 2005. Therefore, only metric measures are taught in Irish schools.

In school, the children are enabled to compare, estimate and measure weight. In the infants classes, the children work with non-standard units (e.g. what is the weight of my pencil case in cubes?) and then they are gradually introduced to the standard metric units of weight i.e. kilogram (first class) and gram (third class). Children in the older classes will also be introduced to, and work with, more complex concepts related to weight, such as converting from one unit of measurement to another (eg grams to kilograms)

Do you know how the metric system came into being? It has an interesting history! Watch this video and/or read this article. For more background info on weight you can read this post from Maths is Fun.

Practical Suggestions for all Children

• In school, the children are enabled to compare, estimate and measure weight. You can reinforce this at home by asking the children to use their outstretched hands to compare and estimate the heavier/lighter of any two items, from anywhere around the house. Do they realise that size is not always indicative of weight? i.e. a bigger item (e.g. beach ball) may be lighter than a smaller item (e.g. a book).

• The children can then check their estimate by using a handmade balance, assembled quickly from a clothes hanger and two identical bags.
• Draw their attention to weight labels on food packaging, especially kg for kilograms and g for grams. Even children who may not yet know that there are 1,000g in a kg, can examine labels and can use their number knowledge to identify the heavier/lighter item. If the food item does not have a weight label, does it have a label for a different unit of measurement and why is this? (e.g. ml or l for capacity).
• Is it good value? Keep a close eye on the weight of various food items when shopping (whether it be in the shops or online): while you’d expect that a 4kg bag of potatoes would be twice the price, or cheaper even, than a 2kg bag of the same potatoes, you would not expect it to be dearer – yet that can sometimes be the case! So involve the children in checking the weight of bags and packages to make sure that you’re getting the best value for your money!
• Involve your child in weighing and measuring when cooking and baking. Show them your kitchen/digital scales (if you have any); demonstrate how it works and get the children to try the scales out for themselves. If using recipes, ask the children to calculate how much of each ingredient would be required to make half, double, etc., of the amount/dish.
• Do you have any other weighing scales at home? Bathroom scales, luggage scales etc? Allow the children to explore how they work and use them to measure the weight of the bags used by the household: school bags, handbags, rucksacks etc.
• 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 weight needs to be considered: weight requirements for children’s car seats, weight restrictions on baggage with airlines, weight restrictions when posting letters and parcels, etc.

Digital Resources for Infants

Homemade balance: This video shows how you can easily set up a balance at home using a hanger and two bags.

Heavy and Light with Ernie & Bert: The Sesame Street favourites explore heavy and light. Other relevant clips include Heavy and Light with Kermit & Grover and Heavy and Light with the Cookie Monster

Number Jacks: Getting heavy

Comparing heavy and light objects: A lesson from Matholia

Measuring Mass (weight) using blocks: A lesson from Matholia. You could do this activity at home using the homemade balance above.

Happy Numbers Pre-kindergarten: Work through the weight activities in Module 5, Topic B. After, move onto Kindergarten, Module 3, Topic C. 

Splash Learn: Compare weight

I know it – Weight: Interactive quiz for Kindergarten. 

Light and heavy: a selection of games from ixl.com. You can do a number of free quizzes each day without having a subscription.

Math Games Choose the Light and Heavy practice games from Junior and Senior Infants

Digital Resources for First and Second Classes

Measure Mass (weight) in kilograms: video from Matholia explaining how to compare the weight of items to 1kg using a balance (you could try this at home using the homemade balance idea in the infant section above).

Using a scale to measure kilograms: A video lesson from Matholia

Mass: A series of video lessons from White Rose Maths, including, for Year 1,  Introduce weight and mass, Measure mass and Compare mass; for Year 2, Compare mass, Measure mass in grams, Measure mass in kilograms

Mostly Postie: Lift the items onto the scales and type in the weight. Recommended: Stick to kg and half kg option.

Happy Camel:  a puzzle game where you must find out where the toy is hidden.

Coconut Ordering Game: Select Mass to order amounts of g and kg. 

I know it – First Grade: Scroll down to Measurement and select the heavier/lighter and metric weight activities. There are similar activities in Second Grade 

Light and heavy: a selection of games from ixl.com. You can do a number of free quizzes each day without having a subscription.

Math Games Choose the Light and Heavy practice games from first and second class.

Digital Resources for Third to Sixth Classes

Metric Mass (weight): Background information on weight (mass) and grams, kilograms and tonnes as the main metric units. At the end of the page there is a link to a Weighing Activity , explaining how you could do some weighing activities at home.

Matholia – Mass: A number of video lessons on mass (weight) that include Measuring Mass with a Scale, Using a Scale – Grams, Using a Scale – Kilograms, Converting Kilograms and Grams to Grams, Converting Grams to Kilograms and Grams and Converting Kilograms to Grams.

Mass: A series of video lessons from White Rose Maths, including, for Year 3,  Measure mass, Compare mass, Add and subtract mass; for Year 5, Metric units; for Year 6, Metric Measures, Convert metric measures, Calculate with metric measures

Khan Academy – Mass and Volume (Third Grade): Watch the videos and then answer the practice questions. Afterwards, for something more challenging,  look at the Fourth Grade activities on Estimating Mass and/or Converting Units of Mass. Or even the Fifth Grade activities on Metric Units of Mass. You can also register for a free Khan Academy account to record your progress and explore other topics/grades.  

Happy Numbers Third Grade: Pupils can do the weight and capacity activities in Module 2, Topic A.  

Mostly Postie: Lift the items onto the scales and type in the weight. Recommendation: work through the given options in order.

Coconut Ordering Game: Select Mass to order amounts of kg and g

Splash Learn – Measurement Games: These games cover how to Estimate Metric Units of Weight and Capacity, Compare Metric Units, Convert Metric Units, Convert Metric Units (Decimal Conversions)

I know it – Third Grade: Scroll down to Measurement (Metric) and select the weight activities. There are similar activities in Fourth Grade and Fifth Grade.

Metric measures of Mass: (ie kg and g) a selection of games from ixl.com. You can do a number of free quizzes each day without having a subscription.

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

Math Games:  Practice games incorporating metric units of mass/weight, capacity and length.

Weight Quiz: (for 6th class) Multiple choice quiz 

9 Weights: A challenging, interactive puzzle from nrich.org