Monkey and hunter

Discussion in 'Supporting Physics' started by MaddyT, Sep 14, 2018.

  1. Hello,

    I am trying to figure out the monkey and the hunter experiment for a teacher but am having a little bit of difficulty in one small area. It is the simplest of things. I have found our "rifle" and "monkey" but am having trouble breaking the circuit. I can not figure out the best way for the foil to be broken when the "bullet" is being fired out. I have posted 2 pictures below. Does anyone have any advice that I could please use.

    https://s15.postimg.cc/7c0e9rcez/Monkey_and_hunter_front.jpg
    https://s15.postimg.cc/yzd3nv5bf/Monkey_and_hunter_side.jpg

    Thank you
     
  2. Dod

    Dod

    A narrower strip of foil should ensure breakage of the circuit or a bigger bullet for the same effect.

    or partially tear the foil.
     
    Ann Chinnery likes this.
  3. PhysicsSimon

    PhysicsSimon COMMITTEE

    Second Dod's comment - that's what we do - narrow strip

    Incidentally, you really don't want to be accidentally holding the leads as the foil tears & breaks the circuit - one of our teachers did it once & described it as really, really painful......back emf is what did it (as the supply to the electromagnet is cut it stops generating a magnetic field - this CHANGE of magnetic field induces its very own current)
     
  4. Thank you, I am going to try again this afternoon, I have almost got there, the thinner strips worked well and it stopped the circuit perfectly. I just need to get the right projectile angle now and play around with what will work.
     
    Ann Chinnery likes this.
  5. PhysicsSimon

    PhysicsSimon COMMITTEE

    Just make sure it's horizontal and at the same height as your monkey - should work fine no matter how far away (sort of the whole point). I use a spirit level myself but I can be a bit OTT like this!:confused:
     
    Ann Chinnery likes this.
  6. I attached a laser to our 'gun' to help with the aiming. I also replaced out 'ammo' from being a large ball bearing to a rubber bung, much safer and just as effective.
     
    Ann Chinnery likes this.
  7. Setting up Monkey and Hunter today. Will try the laser sight :)
     
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  8. I tried this way today with the laser pointer and it worked a treat. We have rubber 'ammo' which worked as well. I am hoping to try at a longer distance tomorrow, see what happens when its not a foot away to start off with :p
     
  9. Nick Mitchener

    Nick Mitchener COMMITTEE

    Did you just scratch that nice top?

    What is the propellant?
     
  10. Haha, definitely wasn't me scratching it although it was unfortunate positioning :p The propellant is 2 thick elastic bands, they're in place of the tinier ones in the side picture.
     
  11. Actually there is no need for it to be horizontal. So long as it is aimed accurately at the 'monkey' it should work.
     
    PhysicsSimon likes this.
  12. PhysicsSimon

    PhysicsSimon COMMITTEE

    Well yes....technically! But when I was at school* the picture in the book was horizontal & that's how I think of it so that's how I set it up......makes me happy anyway!:)

    *A long time ago in a galaxy far, far away
     
    Ann Chinnery likes this.
  13. In case others have trouble with a thin strip of aluminium not being broken (as I used to) you can also attach a wide piece of aluminium to a thin wire so there is a manufactured weak point. We used to use an air rifle which would just push/bend the aluminium foil out of the way.
     
  14. i start a small tear in the aluminium strip to ensure it breaks

     
  15. I use a nerf gun and an old fluffy monkey with a pea tin in its head. fires through Al foil a treat. I must admit the laser is a good idea!
     
  16. This looks fun, I've asked our physics teacher if she would like to try it :D
     
    Ann Chinnery likes this.
  17. I only clip my foil on one side. On the other side I just touch it against the croc clip. That way the foil bends out of the way (and can be reset).