Wave tanks

Discussion in 'Supporting Physics' started by Carol Taylor, May 17, 2019.

  1. Carol Taylor

    Carol Taylor Footsore

    Our very old wave tanks are slowly going to be replaced. Has anyone got suggestions as to good replacements? Not mini ones.
     
  2. We use the Eisco - they're fine
     
  3. As we only demo ripple tank, we have the (not cheap) frederikson one- obviously much cheaper are available, though we tried a cheap one when we first ordered, but sent it back for being far too flimsy..
     
  4. the lascells mini ripple tanks are especially the newer version (mark 3?) are good. They work well each time and are easy to setup. They are designed more for small groups of students to huddle round and use. but they can be setup on an OHP/visualiser for a whole class.
     
  5. 'Ripple tanks' vs 'wave tanks' - they are not the same thing?..... or are they?
     
    Andrew Goloskof likes this.
  6. Nick Mitchener

    Nick Mitchener COMMITTEE

    Wave tanks are usually rather substantial and University based, so I imagine ripple tanks.
     
  7. I first read 'wave' as 'ripple' as to me they are only of the same but then I realised that:
    [​IMG]
    This is a wave tank and:
    [​IMG]
    This is a ripple tank
     
    Andrew Goloskof likes this.
  8. I though so - they are not the same - ripple tanks can measure the frequency, wavelength and speed of waves - but the waves (ripples) are tiny and close together so you cannot measure their amplitude easily.
    A wave tank will produce large well spaced waves so wave amplitude can be measured.
    Edexcel CP4b1 - askes you to use a ripple tank to create a wavelength about half as long as the ripple tank (so you can always see two waves). Impossible using a standard ripple tank!!!!
    With most ripple tanks the vibrator cannot be slowed down enough - you would have to use a wave tank, or, as I did, put reduction gearing on the motor to slow it down enough.
     
  9. Nick Mitchener

    Nick Mitchener COMMITTEE

    Edexcel publish details of using a gratnell tray as a ripple tanks, manually producing waves so you could then.
     
  10. Apologies, meant ripple tank only previously..
     
  11. They had to do to make up for the fact that the ripple tank didn't work, but that's moving a ruler by hand on the water - not very scientific.
     
  12. PhysicsSimon

    PhysicsSimon COMMITTEE

    Still quite nice for measuring the wave speed using different depths of water in the tray - just lift up one end slightly, drop & there'll be a very distinct wave to time - there & back again (2 lengths) seems to be preferred
     
  13. Techitude

    Techitude COMMITTEE

    This is what our teachers like to do with the the kids. First they have a set of the mini ripple tanks and then next lesson they have the trays. Both methods work well and give decent results.
     
  14. If anyone is interested - this is how I adapt a standard cheap ripple tank (SciChem) to produce waves for edexcel CP4 core practical.
    I remove the original vibrator motor (image 1) and replace it with 6v 12mm 100RPM geared down motor with 90 degree locked elbow (superglue) (image 2 and 3)
    I fix it in the same place as the original motor and stick a couple weights on end of nail in elbow (image 4 and 5)
    Then run it as normal with straight edge dipper counter balanced/levelled with three weights stuck along the platform - change voltage to get one or two waves only going across the tank (image 6 and 7)
     

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