New
New
Year 8

# Cooling curve: practical

I can conduct an investigation to create and analyse cooling curves and identify where state changes are happening on temperature vs time graphs.

New
New
Year 8

# Cooling curve: practical

I can conduct an investigation to create and analyse cooling curves and identify where state changes are happening on temperature vs time graphs.

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## Lesson details

### Key learning points

1. State changes are visible as plateaus on cooling curves.
2. As it cools, a substance transfers energy into the surroundings by heating and it may condense or freeze.
3. Energy is released to the surroundings as a substance cools and this is observed as a decrease in substance temperature.
4. Graphs provide a visual representation of data for easier analysis and help identify trends/patterns.

### Common misconception

All substances freeze when really cold, like water.

Show state changes using particle diagrams / kinetic energy model. Challenge pupils to identify state given real world temperature data.

### Keywords

• Plateau - A plateau is a section of a graph that does not change value (stays at the same level for a period of time).

• Melting point - The melting point of a substance is the temperature at which it changes from solid state to a liquid state.

• Freezing - Freezing is the process of a substance changing from a liquid state to a solid state.

• Temperature - Measured using a thermometer (commonly in °C). Temperature is an indirect measure of the energy of the particles in a substance.

This lesson is designed to investigate tert-butyl alcohol (low m.p. of 26℃) but could be adapted to use other substances like salol, stearic acid etc. Check CLEAPSS for guidance. As a result, the lesson's tasks will need to be updated to match.
Teacher tip

### Content guidance

• Equipment requiring safe usage.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
Which of the following is the most appropriate way to show the change in temperature over time?
Bar chart
Pie chart
Q2.
The term used to describe the energy transfer from an object to its surroundings as it cools is...
Q3.
True or false? In the gas state, particles have enough energy to move freely and are not held in fixed positions.
Q4.
What happens to the particles of a substance when it is heated and reaches its boiling point?
They stop moving.
They move closer together.
Correct answer: They move further apart and move more quickly.
They change colour.
Q5.
The temperature at which a substance changes from solid to liquid is known as its...
Correct Answer: melting point, melting-point, meltingpoint
Q6.
Match the state of matter to the description about forces of attraction.
Correct Answer:substances in the solid state,particles have the strongest forces of attraction

particles have the strongest forces of attraction

Correct Answer:substances in the liquid state,particles have some (weakened) forces of attraction

particles have some (weakened) forces of attraction

Correct Answer:substances in the gas state,particles have fully overcome forces of attraction

particles have fully overcome forces of attraction

Q1 image 1 UYSEG Q1 image 2 UYSEG Q1 image 3 UYSEG

## Exit quiz

### 6 Questions

Q1.
On a heating curve, what does a plateau indicate?
A temperature increase.
Correct answer: A constant temperature during a state change.
An error in measurement.
The substance is not changing state.
The substance is no longer being heated.
Q2.
The point on a cooling curve where a liquid starts to solidify is called the point.
Q3.
How does energy transfer during the cooling of a substance?
Energy is absorbed from the surroundings.
Correct answer: Energy is released into the surroundings.
Energy remains constant in the substance.
Q4.
Which state changes are shown in this heating curve?
melting only