Progression of

Children's learning - Mass

Emerging - Developing - Extending are the three phases of learning progression identified in this website. These phases do not necessarily correlate with the school year levels, but reflect the learning progression your child will go through as their understanding and skills related to 'mass' develop during their early years of schooling.

Emerging Phase - Identifying mass as a measurable attribute

Even prior to starting school, children engage in experimentation with ideas of measurement of mass. Through personal experiences in daily life such as lifting or moving heavy objects during play, children develop informal knowledge of mass.

Upon starting school, children’s knowledge about measurement continues to develop as they formally learn about mass as an attribute of measure. Physical objects are used to engage children in hands-on experiences of ‘feeling’ the mass and, in the process, support the development of descriptive language such as ‘heavy’ and ‘light’.

Following closely, children develop an understanding of comparison whereby they are able to compare, order and match objects by mass and use appropriate language - ‘heavier’, ‘lighter’, ‘about the same’, ‘heaviest’ and ‘lightest’. Through hefting or lifting two or more objects children are able to make comparisons and reason their response as to which object is heavier, lighter or about the same. For instance, while hefting two objects of different masses, children may feel and communicate that the heavier object ‘weighs down’ on their hand more than the other. Building on this, a balance scale can be used to extend the children’s understanding of comparison of mass. Seeing the workings of a balance scale e.g. the pan with the heavier object goes down, children develop a theory about the mass of the objects which informs their decisions about how objects can be sorted in order of mass.

It should also be noted, during this early phase of learning about mass, children often hold a misconception that a larger object has a greater mass than a smaller object. Therefore, it is important to provide opportunities for children to compare objects that are small and heavy (like a metal toy car or small bag of marbles) with those that are larger but light (like a balloon or large sheet of paper).

Through the process of comparing the mass of various real-world objects and building language to describe mass, children develop the foundational understanding of mass as an attribute of measure. This prepares the children to move to using units to measure mass.

Source: Jack Hartmann - kids music channel

Developing Phase - Measuring with informal units

In the development phase, children continue to comparing the mass of objects and extend on their understanding gained in the emerging phase. This is done with the introduction of a unit to compare the mass of the object. The focus turns to measuring and quantifying mass and children learn and discover how many units in mass the object is.

The units introduced in the developing phase are informal. Examples of informal units used in measuring mass include counters, coins, metal washers, rocks, cubes, marbles, teddies & fruit. To ensure accuracy these units need to be the mass and are called uniform informal units. It is worth mentioning, however, that opportunity for extended learning could take place if the informal units used are not uniform.

As mass is not a visible attribute, a measuring tool is also introduced to measure the mass of the object using informal units. This is known as an equal-arm balance - seesaws and balances scales are used as a measure. The object being weighed is placed in one pan and informal units e.g. cubes, are added to the opposite pan to the object until it is balanced equally. Children learn that when balanced, the object has the same mass, as the number of cubes that they have added. The video below demonstrates the use of balance scale using informal units well.

Children need a lot of exposure to measuring with informal units to give them an understanding of mass and to make this learning meaningful to them. They learn to record not just the number but also the type of informal units they are using to find the mass of the object.

Possible misconceptions that may be held by children when they are choosing and using informal units to measure can occur as the child may not have grasped an understanding of a unit and that the unit of measure has to be uniform. They may measure the mass of an object with different sized bears and not understand that they are not measuring with bears equal in mass. They also may incorrectly think that because they use more paperclips than metal washers when using a balance, the item weighed by the paperclips may be heavier. Children may also forget to write down the unit when measuring mass. They may need reminding they need number and unit to measure mass.

Once children have had lots of experience measuring mass with informal units and have a sound understanding, they can then progress to measuring with formal units of measurement and be introduced to the kilogram as the standard unit of mass this learnt in the extending phase.

Source: Next Generation Science

Extending Phase - Measuring with Formal Units

At an extending phase, children use familiar metric units when estimating, comparing and measuring the attributes of objects and events, they will choose and use standard (metric) units for estimating and measuring mass, with accuracy. Another area which will be covered is converting these metric units (kg's --> g's or mL --> L). They will use previous strategies like multiplication and division to convert metric units.

Similar to the developing phase, children will still make estimations and provide explanation about what the mass is of item and why. Invoking critical thinking skills during their learning and a better understanding about why they make these estimations.

At a developing phase, students gain knowledge about informal units and familiarise themselves about the differences in mass between different objects, an extending phase further develops their conceptualisation of mass by linking formal units with their understanding. As previously mentioned, mathematical concepts such as multiplication and division is required to convert these metric units which they are familiar with.

Children may have already or will be exposed to various formal units in their everyday life. Identifying the mass of different objects such as flour or milk is a good example of how we can link these concepts in a real world scenario, making it more relevant to the individual and providing a more rich learning experience.

A strong skill for children to grasp when at an extending phase is place value. This makes it easier for children to convert these formal units when dealing with large values.

Potential Misconceptions:
Students may mix up the metric system. They might use kg's when they are meant to use grams or vice versa. Similarly, they might use L's instead of Kg's.
The numeric value might make students believe that 500g of something has more mass than 1kg. Make sure to cover the progression of the metric system so they are aware of how much of each is in another.

Source: Matholia

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