Through fun activities, discussion and digital resources, students model the vibration and movement of atoms and molecules in solids and liquids and use marbles and a clear plastic box to model them. Students also explore the melting of familiar solids placed in a hot water bath. They observe what happens and then answer the question: What is heat?

*Note, please ensure that students have completed the Student Attitude to Science questionnaire and the Hot Stuff knowledge Pre-test before starting Lesson 1.

Students will:

• know that heat is ‘bundles’ of vibrational energy called phonons
• explain that hotter objects have more phonons that vibrate faster
• use models and analogies to explain the effect of heat on atoms and molecules

• Review the Lesson 1 of the Hot Stuff PowerPoint
• The alternative activity will only be effective on a sunny day. Watch the weather forecast a few days before. The activity could be done on a different day before the lesson. Before the lesson identify an outside location in a sunny position for the activity.
• Identify a suitable location where students can stand in a 5X5 or 5X6 grid (grid to match student numbers – doesn’t have to be exact numbers).
• PrimaryConnections has useful teaching resources for teachers not familiar with word walls and science journals:
  • How to use a word wall
  • How to use a science journal
• Read our ‘Using models and analogies in teaching science’ guide.

• rectangular clear plastic container/picture frame (one per group)
• 30 x 1 cm diameter glass marbles, spherical craft beads, or expanded polystyrene spheres per group
• aluminium foil
• butter and crushed ice (in an insulated container)
• a medium sized shallow container
• marbles or small weights

Alternative activity:

• timer
• Copha (coconut oil shortening), butter, and ice per group
• infrared thermometer (optional)

We are starting an exciting topic called Hot Stuff. Students will explore some interesting things about heat and see how this helps us understand our world.

Introduce the Lesson 1 learning intentions using Lesson 1 of the Hot Stuff PowerPoint. Follow the directions under ‘Getting Started‘ if you haven’t done so already.

Before starting to explore heat, though, we need to remind students about atoms and molecules because we use our knowledge of atoms and molecules to learn about heat.

In this lesson we will use a number of models to explain the role atoms and molecules play in our understanding of heat. First, explain that the whole class will model heat energy in atoms and molecules.

As a class we represent a solid object made of atoms and molecules, like a block of ice. This solid will become a liquid and then return to a solid.

A new idea we will learn is that heat energy is passed through a solid by vibrations in tiny ‘bundles’ which we call phonons. The hotter an object is, the more phonons there are.

To begin, students stand on the 5X5 or 5X6 grid (adjust for number of students, the last row does not have to be completely full).

Ask students to jostle backwards and forwards gently – while holding their grid position – to represent the vibration of atoms and molecules in a solid.

Warning: Instruct students to be mindful of their neighbouring ‘atoms and molecules’ by not moving too energetically. They might tread on their toes, or worse still, push them out of the ‘solid’!

The teacher holds up a sign/or tells students: ‘Heat Added’. The students now represent the solid heating up and vibrating a bit more vigorously.

The teacher again holds up a sign or tells students: ‘Heat Added’.

The students then represent the solid melting and becoming a liquid. This is modelled by each student moving a little more energetically and, instead of staying on their fixed grid position, they mingle slowly amongst each other, but still remain quite close together.

The teacher then holds up a second sign or tells students: ‘Heat Removed’. The students then ‘cool’ down a little, moving slower and getting closer together, until they return to being ‘a solid’ in their grid positions.

The teacher leads a discussion about the model and encourages students to answer the following questions:

Consider recording a video of the students as they model a ‘solid’, showing the change to the ‘liquid’ and then back to a ‘solid’.

They then have an opportunity to use their digital devices to examine a set of simple animations that show the differences between how the atoms and/or molecules move and are arranged in solids, liquids, and gases (or view the relevant slide in the PowerPoint). Students then draw their models representing a solid, liquid and gas. 

Gas

Source: Julio Miguel A Enriquez and Monica Muñoz (CC BY-SA 4-0)

Then demonstrate how to make a foil boat by placing a cup in the middle of a foil square and folding up the sides. Then pinch down the sides until the walls are about 1-2 cm tall. Students should make sure that their boats will float by placing them in some cold water and then placing a few marbles into their boats. (You may like to integrate this activity with a separate arts and craft lesson in which students design and build a more sophisticated foil boat. Resources for building foil boats can easily be found on the internet.)

Instruct students to place a small dollop of butter in their boats, then collect some fresh hot tap water and float their boats on the surface of the hot water. Students should record their observations in their science journals.

Then return to the dish of ice and butter. Students should see that the ice has melted, but the butter is still solid.

Review all new words and start the Hot Stuff class Word Wall. Consider including key words learnt in the Atom Frenzy module including atoms, molecules, electrical forces, temperature, etc.

In addition, let students know that in the next lesson we will learn that the Sun provides almost all of the energy needed to produce heat on Earth.

After the Introduction you may wish to use the following activity instead of melting solids in a hot water bath.

Working in groups, place a piece of plastic wrap on some pavement, brick or tile that is in direct sunlight.

Then put a small piece of chocolate, Copha, butter and ice on the plastic in the direct sunlight.

If it is windy, add weights so the plastic does not blow away.

Observe what happens for the first 2 to 3 minutes.

Students then return later during the lesson to observe changes and record these changes in their science journal.

They may use a digital device to take photos of their investigation at the start and at the end of the lesson (alternatively, the teacher could take a photo of one set-up before and after for reference later).

Following the ‘modelling solids, liquids, and gases’ activity, return to the solids in the sun. Ask each group to record their observations about the small pieces of Copha, butter, and ice. If students took photos when setting up the activity earlier, ask them to take photos again to record the changes.

Ask students to work in their groups to report their observations and explain what happened.

Each group writes down what they think heat is. Groups share their ideas with the class; students and teacher come to an agreed definition as a class (the definition should include the movement of atoms/molecules).

The important points for students to understand are that:

• When sunlight strikes each solid and the tile or whatever they or on, photons that make up the light and other radiation are absorbed by the solids and surface.
• These photons turn into bundles of vibrational heat energy (which students will learn are called phonons in the next lesson), which results in the surface and solids getting warmer.

Danger:

• Never look directly at the sun and wear sun protection, particularly if the UV rating for the day is above 3.
• Be careful the tiles are not too hot to handle, they may burn students’ hands.

Atom*: Building blocks of all matter.

Molecule*: Two or more atoms held together by electric forces.

Vibration: Moving backwards and forwards, often about a fixed position.

Photons (if introduced): Individual ‘packets’ or ‘bundles’ of light or other electromagnetic radiation that carry energy and can travel through a vacuum.

Phonons: Bundles of vibrational heat energy in materials.

Solid: A solid is something which has a fixed shape and size or volume because its atoms and molecules are held closely together in fixed positions by strong electric forces. The atoms and molecules vibrate about their fixed positions.

Liquid: A liquid is something which has a fixed size or volume because the atoms and molecules are held closely together but its shape changes because its atoms and molecules are free to ‘mingle’ amongst one another because the the atoms and molecules are vibrating and jiggling too strongly for the forces between then to hold them in place.

Gas: A gas is something in which the atoms and molecules spread out and fill the container it is in because the atoms and molecules have vibrated and jiggled so strongly that they can break completely free from each other.

The following diagram provides a visual model of solids, liquids, and gases:

https://www.sciencelearn.org.nz/images/1839-three-states-of-matter

Model: Scientists use models to help understand the nature of the natural world. Models help us visualize or picture in our mind what something is like that is difficult or impossible to see. Models use familiar objects to represent these things that are difficult or impossible to see. A model can be a diagram or drawing such as the above example, a physical object (like a Nerf gun bullet), or a mathematical relationship (e.g., speed is distance travelled divided by time taken).

*Review from Atom Frenzy