# Help needed with giving particles lesson a *wow* factor

Discussion in 'Science' started by LavaLaura, Dec 1, 2011.

1. ### LavaLaura

I'm a PGCE student and I'm three lessons in to the Y7 particles topic.
Today my observation was that my lesson needed a bit more 'oomph' (standing on the tables was suggested, but that's not really me!). Any ideas?
The scheme of work has the following learning outcomes:
Describe the motion of gas particles.
Explain how a substance diffuses using the particle theory
Use the particle model to explain how the speed of diffusion can be affected
I'm thinking of a title (which the teacher likes to be a question) of: How can you smell my perfume on the other side of the room? and a WALT of: What happens to the particles in a gas after they escape from a container.
My suggested teaching and learning ideas are:
Demonstration of experiments to illustrate diffusion : coloured crystals in water; aerosol deodorant or air freshener;
Demonstration of experiments which illustrate gas pressure: collapsing can; air pressure circus
Use observations and secondary sources to present explanations for diffusion and gas pressure.
This is a mixed ability year 7 class with y9 targets ranging from L4-L7.
Any ideas gratefully recieved, I would love to get a really good review from this teacher!

2. ### PinkHelenNew commenter

Get the pupils to act out particles in a gas, then develop this by giving half of them blue cards (e.g. for air) and red cards (e.g. for perfume) - for this, have all the red cards start out in a corner and the blues filling up the room, and then when you say "go" they can all begin to move as gas particles. Once this has been done, ask the pupils to suggest how this could be made quicker/slower using their knowledge of the particle model. For higher ability pupils you could also possibly build in some kind of challenge about why their model of the air is not perfect - they might recognise that the air is not made up of just one gas (and therefore not just one colour card).

It's not really "wow", but it gets the pupils moving and they always enjoy it. Just be sure to set clear rules for how to behave whilst imitating gas particles, or they'll all go bashing into each other and knocking each other down!

3. ### LavaLaura

Thanks Helen, I really like that idea. I've done the S L G roleplay before with younger kids, but hadn't thought of extending it like this.

Agree with Helen, some excellent ideas there.
If you have some high-flyers they might also realise that their movement in the model might not be random, and you could ask them how it could become random (blindfold them!).
Modelling solids, liquids and gases is great fun - they can do it themselves or use marbles in a tray (great if they like making loads of noise, not so good for you if you have a headache!).
Using themselves to model a solid melting or a liquid evaporating never fails to make me laugh.
You can also squeeze in some AfL and peer marking by asking groups to act out their model and get others watching to say what was good about it and how they might improve it.
One of my favourite lessons!

5. ### physics_suits_you

I've got nothing to add except to say how good it is to see someone airing their plans and asking for advice rather than just saying "what shall I do?".
Good luck and enjoy a great career.

6. ### robbywilliams66

A nice little demo showing diffusion.
You need;
an OHP (you know the old type that you display transparencies from),
a clear petri dish half-filled with distilled water,
a crystal of lead nitrate and a crystal of potassium iodide.
The petri dish (with the water in) goes onto the OHP so that it's image can be projected.
Simultaneously place both of the crystals in the water at opposite sides of the petri dish.
The particles will diffuse through the water from the crystals and where they meet will form an immediate dense and yellow precipitate.
The precipitate will form a curved yellow line closer to the potassium iodide crystal than to the lead nitrate crystal. Curved because the ions diffuse radially and closer to the lead nitrate crystal because the lead ions will diffuse at a slower rate than the Iodide ions due to their greater mass.
If you can't get an OHP then you can still demo this in fron of them. You need to keep the water still and calm.

7. ### physics_suits_you

It's a good demo BUT check if it's used in KS4, as teachers need something "new" to grip their attention when it comes to extending the work to a higher level (in this case, speed of diffusion).

8. ### robbywilliams66

Doesn't really matter does it?
You can use such a demo at KS3 to show diffusion and to demonstrate that it doen't occur just in gases.
You can use it at KS4 and talk about the relative masses of the lead and iodide ions and how that affects the rate of diffusion.
This is just safer than using the classic NH3/HCl diffusion tube demo.

9. ### MagisterArtium

Classic NH4 + HCl in glass tube - simples!
http://www.practicalphysics.org/go/Experiment_170.html

10. ### robbywilliams66

Seeing as we are talking about a trainee teacher and a year 7 class then I would strongly suggest that the OP discusses the safety aspects with the HOD before planning to use this demo. Make sure you carefully read the safety guidance given since you are dealing with two rather hazardous liquids.

11. ### LavaLaura

Thanks for all the input! I'll note the ideas and discuss them with the class teacher.