Materials for the lesson

Cd-Player,
Cd with sounds : a. strong wind (Winter-cold))
and b. cicadas (Summer-hot).

Υou can find sound files at
https://www.partnersinrhyme.com/soundfx/Weather.shtml
http://findsounds.com/
https://freesound.org/browse

Chalks: Blue, Red
The Teachers bell ( to start-stop-intervene)

Layout of the classroom

The classroom adapts in such a way so as to have enough space for action.

1^st Phase

A. The teacher makes a prologue to the children about solids. Explaining that solid matter consists of smaller particles, called molecules.  He/she goes on to explain that, in action, each student will play the role of a molecule of some solid matter.

B. The teacher and the students discuss about the climate conditions, temperature changes (hot-cold, winter-summer) and the sense of they create.

2d Phase

1.           The teacher introduces the condition that it is Summer. (the cicadas on the cd player).
Teacher’s Bell rings and the action starts.
The children are feeling hot and are moving about the class making air with their writing books.  They can state with every way they can imagine that they feel hot, moving away from each other for more fresh air etc.

Teachers Bell: Action freezes. The teacher (or one of the students make a circle on the floor with the chalk.  A perimeter (circle, square or a random form) that includes all the team.  It will be a quite big form as it has to include all the children that are walking freely all around the space.

3d Phase

Now the condition is that it is winter and it is cold.
The CD changes and we hear the sound of freezing winter wind. The teacher’s bell rings again. The children, with their body movements, start expressing that they are cold and are moving together in the center, near to each other to warm up.

The bell rings again and action freezes once more. A circle/form is drawn to include all the students that is much smaller now than the one before. The teacher explains that this is what correspondingly happens to solid maters according to the temperature.

The bell rings again and the children are encouraged to repeat the action and movement passing form cold to hot and from the smaller form/space to the larger.

In the end, all stand outside the two forms and compare them, asserting that when we are cold we occupy less space. As opposed to heat that we are sparsely and we occupy more space.

4^th Phase

Children return to their desks. The teacher teaches this particular chapter of expansion and contraction according to what is presented in the book. Wherever needed the teacher relates the previous action of the children with the phenomenon noticed in solids.