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To investigate changes of state

Science - Particles

Miss Pollock

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Key principles

The I do phase involves the explanation - indicates where a teacher would be explaining and modelling a concept.

Moving from I do to We do involves guided practice - moving from teacher-led instruction to student-led practice.

Check for Understanding - Formative instruction questions, posed to check whether students have understood and to inform next instructional steps.

You do - Practice - indicates places where students will attempt questions independently.

At the expected level for the lesson; all students should be able to do these questions.

A small increase in difficulty from the expected level, eg larger numbers or a more complex calculation.

Extension - increased difficulty; suitable for a small number of students.

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I

CfU

W

Y

Support - support materials, such as additional templates or questions with fewer steps.

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Engagement icons - to go in top right corner

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Whiteboard response

All students respond to the teacher’s question, showing their responses at the same time.

Non-volunteers

The teacher asks a question, gives wait time, then calls on individual students to respond.

Written response

Students respond to a prompt in a template, their exercise book or booklet.

Pair share

Students discuss with the person next to them.

Choral response

Students respond orally all together.

Thumbs up, thumbs down

Students indicate whether they agree or disagree with a statement, or whether something is an example or non-example.

Concrete materials

Teacher might choose to illustrate this teaching point using concrete materials.

Class discussion or activity

Students discuss as a class and share ideas

Calculator

Students will need a calculator to perform the task on this slide.

Spreadsheet

Students will need access to spreadsheet software to perform the task on this slide.

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Exercise book or paper

Pencil

Image credit: Pixabay

In this lesson, you will need:

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Starter quiz

Recap previous lessons

Melting point and boiling point data

Plot secondary data

Exit quiz

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Keywords

Melting: is when a substance changes from a solid to a liquid.

Melting point: is the temperature at which a solid substance turns into a liquid (melts).

Boiling: is when a liquid becomes a gas.

Boiling point: is the temperature at which a substance boils.

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Recap of previous lesson

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Boiling

Boiling is when a liquid becomes a gas - remember, this is evaporation!

Evaporation happens so quickly that bubbles of gas form in the liquid and the gas escapes as the bubbles burst at the top of the surface.

During boiling, the entire substance is heated.

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Credit: Pixabay

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Melting

Melting is when a substance changes from a solid to a liquid. This happens when heat is transferred or applied to the solid.

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Credit: Pixabay

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Solids and liquids

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Melting

  • Particles lose their attraction towards each other
  • Particles move further apart

Solid

Liquid

Credit: Free SVG

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Liquids and gases

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Boiling/

evaporation

  • Particles lose their attraction towards each other
  • Particles move further apart

Liquid

Gas

Credit: Free SVG

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Melting point

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Melting

Melting is when a substance changes from a solid to a liquid. This happens when heat is transferred or applied to the solid.

Melting point is the temperature at which a solid substance turns into a liquid (melts).

The melting point of water is 0°C.

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Credit: Pixabay

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What is the melting point of the chocolate?

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Credit: Pixabay

Temperature

State

15°C

Solid

25°C

Solid

45°C

Liquid

50°C

Liquid

55°C

Solid

CfU

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Boiling point

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Boiling point

The boiling point is the temperature at which a substance boils. The boiling point of water is 100°C.

It can also be thought of as the temperature at which a liquid changes to a gas.

A liquid will stay at its boiling point until all liquid has transformed into gas.

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Boiling points change when above sea level

As you move away from the earth’s surface or go above sea level, the air gets thinner and the air pressure gets lower.

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Sea level

Above sea level

Credit: Free SVG

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Point to sea level and above sea level on your screen

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Sea level

Above sea level

Credit: Free SVG

CfU

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Boiling points change when above sea level

If you were climbing a huge mountain and wanted to boil some water for noodles at the very top of the mountain, the water would boil around

70°C rather than 100°C.

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Credit: Free SVG

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Fill in the blanks

Melting point = solid

Boiling point = liquid

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Liquid

Gas

CfU

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What is the melting and boiling point of water?

Melting point = 0°C

Boiling point = 100°C

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CfU

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Melting and boiling point data

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Melting and boiling points of water

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Temperature °C

140°C

-30°C

-10°C

0°C

20°C

40°C

60°C

80°C

100°C

120°C

160°C

180°C

SOLID

LIQUID

GAS

Melting point

Boiling point

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Melting and boiling point of water

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Substance

Melting point (°C)

Boiling point (°C)

Water

           0

     100

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Identify the column for melting and boiling point

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Substance

_________ point (°C)

_________ point (°C)

Water

           0

     100

CfU

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Identify the column for melting and boiling point

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Substance

Melting point (°C)

Boiling point (°C)

Water

           0

     100

CfU

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Table salt

Melting point: 804°C Boiling point: 1413°C

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Temperature

State of matter

Reason

22°C (room temperature)

Solid

Table salt is a solid until it melts at 804°C and becomes a liquid.

805°C

Liquid

Table salt’s melting point is 804°C, so it is a liquid when it reaches above 804°C.

3000°C

Gas

Table salt’s boiling point is 1413°C, so at any temperature above 1413°C it will be a gas.

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Develop a reason for why each state of matter belongs to each temperature for iron.

Melting point: 1535°C Boiling point: 2750°C

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Temperature

State of matter

Reason

22°C (room temperature)

Solid

1550°C

Liquid

3000°C

Gas

CfU

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Develop a reason for why each state of matter belongs to each temperature for iron.

Melting point: 1535°C Boiling point: 2750°C

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Temperature

State of matter

Reason

22°C (room temperature)

Solid

Iron is a solid until it melts at 1535°C

1550°C

Liquid

Iron’s melting point is 1535°C

3000°C

Gas

Iron’s boiling point is 2750°C

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Plotting melting and boiling point data

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Components of a graph

Title

Y axis

X axis

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Temperature °C

100°C

0°C

-100°C

Heating curve of water

Time

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Plotting the boiling point and melting point of water

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Temperature °C

SOLID

LIQUID

GAS

Time

100°C

0°C

-100°C

Boiling point

Melting point

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Has the student plotted the melting and boiling point of iron correctly?

Melting point: 804°C

Boiling point: 1413°C

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Temperature °C

SOLID

LIQUID

GAS

Time

1450°C

804°C

0°C

Boiling point

Melting point

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To investigate changes of state: worksheet

You can use the optional graph template and the sentence starters. However, if you are feeling up to the challenge, ignore the sentence starters and graph template.

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Worksheet Answers

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Temperature °C

SOLID

LIQUID

GAS

Time

800°C

400°C

0°C

Boiling point

Melting point

Heating curve for potassium

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Using the particle model explain why the melting point of potassium is 63.5°C and its boiling point is 758.8°C.

The melting point of potassium is 63.5°C because this is the temperature where it changes from a solid to a liquid. When it is a solid, the particles are close together and the particles are highly attracted to each other; however, when it reaches its melting point, the particles are far away from each other as they lose attraction. At its boiling point, it changes state from liquid to gas as the particles lose more attraction and become spread apart even further from each other.

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Starter quiz

Recap previous lessons

Melting point and boiling point data

Plot secondary data

Exit quiz

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