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practical ideas for interview

Discussion in 'Science' started by brandy1810, Apr 29, 2011.

  1. hi, i am a student teacher and i have an interview next week and they have asked me to teach a how science works lesson. its one hour long to year 10 and want me to carry out a practical and draw a graph. Can you think of any straightforward practicals that doesnt involve lots of health and safety or lots of equipment? i also would like to do a chemistry practical as even though i am a biologist, biology practicals are usually slow and unreliable, and i hate physics! Any ideas would be much appreciate. thanks.
  2. blazer

    blazer Star commenter

    One that springs to mind would be rates of Reaction. They won't tackle it till yr 11 so it will be new to them.

    Get some 1cm pieces of Mg ribbon and HCl in 2 concentrations. (between 2 and 0.5M). Boiling tubes and stopclocks.

    They can time how long it takes for the Mg to be used up in each conc and then plot a graph of time vs Conc with Conc on the x axis as it is the independent variable (remember 'Babies nappies', the thing you change goes on the bottom)!

    You could discuss reliability (they only do each conc once so how could you make it more reliable (the answer is share class results)). You could have a big table on the whiteboard/blackboard/screen and get each group to put their results in as they go along. Then you can look for anomalies, work out means and the plot the graph. If they are really high ability you could plot Rate (1/time) vs Conc but that may be a bit too much for 1 lesson. You will also find that the 2M results are a bit too long because the ribbon floats on a raft of bubbles and does not come into full contact with the acid. You can eiher leave this and discuss it as a source of error or ask the techies for some glass rods and get the groups to push the Mg down into the acid. 5 points on the graph is the minimum number required to be able to spot a pattern (apparently) also the conc is a continuous variable and so you plot a line graph. They will also have to draw a curved line of best fit which is a skill in itself!

  3. blazer

    blazer Star commenter

    That should have been HCl in 5 concentrations!
  4. For 'How Science works' you could bring things back to everyday activities such as dissolving sugar in tea - get the pupils to add a given amount of sugar to water at different temperatures & see how long it takes to dissolve ==> graph of temperature against time to dissolve. You will have to leave the tea bag out in order to 'see' when the sugar is disssolved. You can even try this expt out at home to get some sample data & an idea of timing. Extension work could be to use sugar lumps.
    Alternatively, get pupils to boil 200g then 400g and, if time, 600g of water in a beaker. Take readings of temp as time passes (each 30 seconds for 10 mins OR stopwhen water boils, whichever happens first). Graphs of temp (y) against time (x) for each volume (on the same graph) & discussion of how to save energy when you boil the kettle for one cup of tea.
    Some pupils may already have done these experiments by Y10 though.
    A physics one: get some paper cup-cake cases & muffin-cake cases (different sizes) and pupils compare the average time it takes for the cases to fall a given distance. ==> graph of x-sectional area against time. They can then measure the masses & do the same experiment with the cases scrunched up into as small a ball as possible ==> graph of mass against time & discussion of how x-sectional area influences speed of fall.

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