Acid Rain Demo

Discussion in 'Science Technicians - General Discussion' started by Rachel Heeks, Jun 13, 2019.

  1. Teacher requested to demo acid rain. In a previous school this was done in a dessicator with matches soaked in water and then rolled in sulphur with a petri dish of uvi and water. when I tried this I got a mini whoos h with an immediate colour change. Any suggestions on a better experiment. She wants to show SO2 causes acid rain.
     
  2. Hmm you could try making the SO2 gas as per CLEAPSS recipe sheet 96. The gas made can then be bubbled through some water containing universal indicator. The green colour should go to red pretty quickly.
     
  3. Fill a gas jar with oxygen but leave approx 3cm of water in it. Put a few drops of UI indicator in trying not to let too much oxygen out.

    Burn some sulphur on a defrag spoon (again try and swap it before letting too much oxygen out)

    The red layer sits on top quite nicely
     
    Last edited: Jun 13, 2019
    Emil Retaw likes this.
  4. Exactly what I was about to suggest! So easy to produce as a demo too!
     
  5. Yeah this is much better and easier!
     
  6. Get a 2l beaker put cotton wool in the bottom with a little 1M H2SO4, tie a bundle of matches with wire and hang over the edge of the beaker. Find a lid that fits, a large clock glass would work. ( We used a draught excluder lid for a balance) In front of the class, light the matches and put the lid on. when the fire goes out and the beaker is full of smoke, put about 20mls water in the beaker and test with UI. Lo and behold acid rain!!!
     
    Tony Worthy likes this.
  7. we tie a bundle of about 20 matches with bare nichrome wire ( or similar ), with a long cooks match in the middle of the bundle. leave a long piece of wire to suspend the matches in the flask
    UI and water in the bottom of a large 2 litre conical or flat bottom flask. suspend the matches and light the center long match with a wooden spill .
    Plug the mouth of the flask with rock wool and wait for the matches to burn. (wear heatproof gloves and goggles,)
     

    Attached Files:

  8. A student teacher did this microscale acid rain demo :)
     

    Attached Files:

  9. Techitude

    Techitude COMMITTEE

    Ours do it the same way for a demo and as a class practical.
    Pour a few cms depth of water in a gas jar, add some UI. Get three matches tied on a long piece of spring, light them and immediately lower them in to the gas jar. Hold a wet cotton wool pad over the top. Once the matches have gone out swirl the water in the bottom and observe the colour change.
    It was already being done that way when I started at the school and the teachers like it so I havent changed it.
     
  10. I never liked that demo but if you go to I have a diffusion method which is probabaly more for A level. The interesting reacions is where the BaCl2 solution stays colourless in SO2 gas but if hydrogen peroxide is added, it goes cloudy. This shows that sulfur dioxde has oxidsed to sulfur troxide to make a strong acid. Oxygen radicals and ozone in the atmosphere can do this.