1. Equipment Slide 2 printed per student
Slide 3 printed per student – optional task
Green pens
Circus of activities – see technician notes.

2. Reversible or irreversible? Physical or chemical change?
Experiment
Reversible or irreversible?
Physical or chemical change?
How can you tell?
What is happening to the particles?
Burning toast
Ice melting
Dissolving sugar
Water boiling
Cooking an egg
Magnesium in acid
Bunsen burner on

3. Retrieval practice
1) What is the missing gap 1. 2) What is missing gap 2. 3) Describe the change of state ‘condensing’ in terms of closeness, arrangement and motion of particles? 4) What state are these at RT? Nitrogen Osmium Oxygen Mercury 1 2

4. What is happening? Can they be reversed?
TWWL: about chemical and physical changes SO THAT I CAN…
Identify physical and chemical changes
Describe the difference between chemical and physical changes
Explain what happens to the particles during chemical and physical changes
14/11/2018
What is happening? Can they be reversed?
Energy and direction

5. Reactions How can we tell if a chemical reaction has happened? Noises
Flames or sparks
Smells
Change in temperature
How can we tell if a chemical reaction has happened?
Light energy given out
Change in colour
The mass changes – a gas has escaped
Change in colour
Bubbles of a gas are made

6. Reactions Chemical change Physical change
In the physical change the molecules look the same but are arranged differently
In the chemical change the molecules are different

7. Chemical or physical? Can you change a raw egg into a cooked egg?
Forwards
Backwards
Can you change a cooked egg into a raw egg?
Discuss whether you can go backwards from this previously seen picture. Get students to pronounce irreversible and ask if anyone knows what it is before telling.

8. Chemical or physical? Can you change water into ice? Forwards
Backwards
Can you change ice into water?
Discuss whether both of these steps are possible.

9. Reversible or irreversible? Physical or chemical change?
Experiment
Reversible or irreversible?
Physical or chemical change?
How can you tell?
What is happening to the particles?
Burning toast
Fireworks
Ice cream melting
Dissolving sugar
Water boiling
Cooking an egg
Magnesium in acid
Melting chocolate
Copper sulphate and zinc
Bunsen burner on

10. Rules
Task: Write 4 rules to help someone who hasn’t done this lesson work out whether a reaction is:
Physical
Chemical
Irreversible
Reversible

11. Reflection How do you feel about today’s objectives?
Choose a face and write why you feel this way
(I think I can now _______ because ______________)
Identify physical and chemical changes
Describe the difference between chemical and physical changes
Explain what happens to the particles during chemical and physical changes.

12. Optional task

13. Chemical or physical?
The candle has been burning for a while The wax is the fuel Has the wax been used up? Is there any physical or chemical change?