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Interview lesson

Discussion in 'Science' started by pink_reindeer, Feb 15, 2012.

  1. pink_reindeer

    pink_reindeer Occasional commenter

    Hi. I received a letter inviting me to an interview, with the lesson to be taught: "20 minutes presenting a topic that is based on a point on the range 'Sustainable Earth' in the National Curriculum, namely:
    The properties of solids, liquids and gases and how the particle model can be used to explain these properties.

    The pupils have already studied the unit this year, so applicants are asked to extend the pupils and talks about the effects such as expansion, diffusion or change state."


    Sorry all this messaged is squished up. I STILL don't know how to do paragraphing on here!! So, anyway, my questions are what is it do you think the pupils have studied if they haven't done change of state? The lesson is to be taught to a higher ability y8 group. From the information above, would you assume that they've done melting, condensing, freezing etc? I can't really organise in my head what to teach, where to pitch it? I had an idea about diffusion, but then think maybe freezing and melting etc would be easier. Was thinking I could do the balloons in a box of ice, box of hot water? A 'thermometer' to show that the liquid is expanding. What do you think? Any ideas a very greatly appreciated!! Thanks.
     
  2. pink_reindeer

    pink_reindeer Occasional commenter

    Hi. I received a letter inviting me to an interview, with the lesson to be taught: "20 minutes presenting a topic that is based on a point on the range 'Sustainable Earth' in the National Curriculum, namely:
    The properties of solids, liquids and gases and how the particle model can be used to explain these properties.

    The pupils have already studied the unit this year, so applicants are asked to extend the pupils and talks about the effects such as expansion, diffusion or change state."


    Sorry all this messaged is squished up. I STILL don't know how to do paragraphing on here!! So, anyway, my questions are what is it do you think the pupils have studied if they haven't done change of state? The lesson is to be taught to a higher ability y8 group. From the information above, would you assume that they've done melting, condensing, freezing etc? I can't really organise in my head what to teach, where to pitch it? I had an idea about diffusion, but then think maybe freezing and melting etc would be easier. Was thinking I could do the balloons in a box of ice, box of hot water? A 'thermometer' to show that the liquid is expanding. What do you think? Any ideas a very greatly appreciated!! Thanks.
     
  3. blazer

    blazer Star commenter

    Collapsing can is good if you can find a metal can! You can also do it with a coke can inverted in a trough of cold water but that takes practice.

    They could make their own thermometers using boiling tubes with capillary tubing through the bungs! They could place them in beakers of cold and warm water to see the difference. Put some food colour in the water to make it easier to see in the capillary.

    Does the school have any ball and rings so you could show expansion of solids?

    The balloon idea works well. Get the kids to blow up a balloon and tie it off. hen they cut a peice of string exactly long enough to go round. Then they can warm up the balloon and see that the string is now too short. Cool the balloon down and the string is too long. Observing te balloon will probably not be enough to see a change.

    One thing all kids seem to have a problem with is the idea that something can 'boil' at a very low temp eg Oxygen and 'freeze' at a very high temp eg Iron and that the state we observe materials to be in is their state at room temp (approx 20 degrees C).



     
  4. pink_reindeer

    pink_reindeer Occasional commenter

    Thanks, had forgotten about the collapsing can idea. The only thing is, besides random demos etc I'm wondering what else I can get the pupils doing. How about getting them to act as particles - packed together and moving slightly for solid, then moving a little bit more to be liquid and then moving very quickly and far apart as gas particles? I read an idea on here somewhere once about getting a huge rope to put around them showing that as the solid gets heated the particles move more, therefore expands? And then of course can reinforce using the ball and ring? Should I just focus on expansion and change of state or do I need to bring diffusion in too?
     
  5. blazer

    blazer Star commenter

    Trouble is with role play stuff is that you don't know the kids and you only have 20 minutes. It could take that long to explain what you want them to do. Also do you know that the room has enough space?

    You could do a card sort with diagrams of particles and get them to decide solid, liquid or gas. (a bit of AfL as a starter)
     
  6. pink_reindeer

    pink_reindeer Occasional commenter

    Good point. I'd thought of the card sort thing too thanks. I have a true/false game to play at the end too, which should be a bit more afl!!
     
  7. pink_reindeer

    pink_reindeer Occasional commenter

    Can I ask about the contracting can demo? Is it the can (I.e. the metal that expands/contracts) or the gas inside?
     
  8. ferrisbueller

    ferrisbueller New commenter

    Coke cans containing a small quantity of water
    are heated until the water boils. Steam (gaseous water), fills the can
    and pushes the air out the hole in the tops.
    After
    the can has filled with steam, it is quickly immersed in a container
    of ice water.The steam is
    cooled in the ice water and condenses to a small quantity of liquid
    water. Condensation of steam to liquid water creates a vacuum inside
    the can. Atmospheric pressure outside the can is higher,
    while pressure inside the can is much less. The can collapses because
    of the pressure difference.
    Great demo !! just try it out first and safety is VERY important :)
     
  9. Have done the coke can many time myself but it really does stink! Think the role model stuff is a very good idea. Top set year 8 for 20 mins am sure you will keep them active and entertained. To finish off the lesson what about the upturned glass of water above a pupils head? Bit risky but great fun, even if it doesnt work. Just ask for a volunteer and put a towel around his/her shoulders. Then get the pupils to explain why the liquid did not pour out over little john.
     
  10. ferrisbueller

    ferrisbueller New commenter

    Depends how you introduce it. Many students think that 'air' is weightless, when in fact it weighs a considerable amount, and therefore exerts pressure on objects. I wouldn't just do this demo, probably several others, that wouldn't take more than 5 mins.

     
  11. pink_reindeer

    pink_reindeer Occasional commenter

    I think I'm going to two balloons with string around them, one in ice, one in hot water. See the effects. Then expansion/contraction of liquid demo, using a boiling tube thermometer, then expansion of solid using the ball and hoop thingy. I am going to get a few of the pupils to act as particles in a solid, hold them together with rope, give them energy, move around more, showing that the solid itself expands rather than the particles getting bigger. I have a card sort for the starter on properties and particle theory of solids/liquids/gases. I have a true/false game for my plenary. If I need another activity, they can choose one of the demonstrations to describe and their description must include the words expansion/contraction. What do you think?
     
  12. blazer

    blazer Star commenter

    Just a quick addition. The can has to be inverted before imersion in the cold water! You only have to put the top 1cm of the can in the water, practice first because it will make you jump the first time you do it.

    The classic collapsing can uses a 5 litre (or in the good old days a Gallon) metal can. You take the lid off and heat the can with a bunsen burner, screw the lid back on and leave to cool.
     
  13. blazer

    blazer Star commenter

    I've never notices a smell! Did you rinse the can out first?
     
  14. blazer

    blazer Star commenter


    Sounds good, let us know how you got on. Our advisor fees are quite reasonable[​IMG]
     
  15. pink_reindeer

    pink_reindeer Occasional commenter

    I didn't get it. I don't know why as feedback hasn't been given yet. I have to phone for it and I never seem to have the time.
     

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