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Acid advice please. (and diseases)

Discussion in 'Science' started by Kate_45, Mar 7, 2011.

  1. Hello. I couldn't see a lab technician board and so I thought I'd ask for help on here.
    I don't work in a school, but in science communication. I am doing a workshop soon on disease transfer and as part of that I was going to do the exercise where there are lots of testubes of water, one with acid and they go around with pipettes transferring one drop to every person they encounter. As the end we test them all with UI strips and see how many people are "infected"
    We tend to do most of our acid work with vinegar, but this won't be suitable for this case so I was wondering what you would recommend we order from phillips harris, or if there is indeed a high street alternative that would be strong enough to give a positive result with just one droplet.
    Thank you very much.
    Also if anyone has any good interactive ideas about disease transfer/prevention/testing then I'd love to hear them.
    Thanks
    Kate
     
  2. I do the same thing with very dilute sodium hydroxide for the 'infected' student. Each student swaps 'body fluids' with five others and at the end test beakers with phenolphthalein indicator. Also seen similar done with UV hair gel and hand shaking. The 'reveal' is done with a hand held UV light. Very effective.
     
  3. ferrisbueller

    ferrisbueller New commenter

    I have a very safe method
    Use milk in test tubes and just add some starch into one of them. Use straws to ask students to transfer to other test tubes. To do this just place the straw in the test tube of milk, put your finger over the top of the straw, remove and then place straw over other test tube and move your finger.
    At the end, bring them all to the front, asking people to remember which ones are theirs and then just add iodine to each.
    The infected tubes instantly turn blue/black, with the person spreading the disease having the darkest blue/black tube.
     
  4. I have done this but in a completely different way - I used glitter hair gel and spread it all over my hands then shook hands with about 4 students in the class. They were then instructed to pass out rulers and pencils for the rest of the class to use. Once they had done that I asked them all to look at their hands and see who had glitter on. This was to show them how easy it is to pass germs through no/poor hand washing or the sneezing into hands thing!
    We also used the light testing one where they washed their hands then put them under the light to check for unwashed places. ( Local hospitals may be useful for this sort of information and the use of the light boxes)

    hope that helps
    Taitie
     
  5. the hairgel one reminded me of another - I put some glitter in some hair gel (very fine glitter) and cover my hands with it - not very much, then shake hands with the pupils as they enter the room. We then discuss the glitter representing bacteria colonies. Quite effective too!
     
  6. great minds Taitie! we posted almost at the same time!
     
  7. phlogiston

    phlogiston Star commenter

    Much good advice above.
    Have you thought about using citric acid instead of vinegar - easily available from chemists shop.
    I would be wary of sodium hydroxide - much nastier than acids. Not good for KS2!
    P
     
  8. Thanks everybody!
    I never thought of white vinegar - donkey!
    Will go out shopping for either citric acid or that today, test it to see if it works before approaching a local school if necessary.
    I agree UI solution would give a more impressive final result, but we already have the UI strips so may as well use them.
    thank you for the prompt and helpful response.
    Kate
     

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