Lesson 1

Aims:
To bring back pupils' knowledge acquired in past years related to the concept of measuring;
To utilize arbitrary standard units for measuring.

Materials:
Bottles of juice and drinking glasses

Introduction:

In past years, pupils have already made several measuring experiences; so, to avoid lacks in motivation, teacher has decided to start from a situation concerned with pupils' life: a birthday party.

Roundup:

To bring back pupils' concept of measuring, it was a good moment that one in which birthday boy was given some juice to his classmates.

Teacher asked to pupils to describe what their classmate was going to do in that moment; they first answered:

•  He gives us some juice! –

And then:

•  He fractionizes the “whole” which is bottle's content!

Furthermore, teacher has driven pupils to notice that a bottle of juice might be considered as a “quantity” and so it might be measured.

He has brought back to pupils' memory some measuring experiences made with different lengths and standards: pencils, rubbers, foot, metres, etc.

This experience has enabled pupils to consider a glass as a standard, and a full glass' amount as a measuring.

In this way, it was simple for children to remember what's the meaning of measuring: to measure a “quantity” it's important to notice how many times the considered standard is contained in the quantity itself.

Lesson 2

Aims:

•  To be able to change from measuring given standards to equivalent others.

Materials:
Some cups and a syringe

Introduction:
Teacher has intentionally changed standard units; he has suggested pupils to pour out the content of a bottle of juice into some small cups.

Furthermore, he has suggested pupils to use another standard, a syringe; for this experiment, quantity to measure was the content of a cup.

Teacher's last suggestion has been intentional: it has driven pupils to understand that to measure both standard and bottle's content by using a syringe, it was necessary to make a multiplication.

Roundup:
By observing experiments' results, pupils have understood that it is possible to establish an equivalence by using different standards.

Making constant reference to concrete situations has favoured pupils' comprehension of some maths' concepts not easy to assimilate.

In particular, pupils have noticed that when standards' capacity has decreased, number's measuring has increased.

Furthermore, these experiments have favoured the comprehension of next lesson's concept related to measure of capacity.

In fact, pupils have easily understood that to change from a given measure to an equivalent one it is necessary to multiply by 10 – 100 – 1000.