My Dad has an awesome background of science, when I saw the science contest I asked him for ideas on what to do - the result is Eddy currents.
In this 'ible you should learn what an eddy current is and how they occur and how to make them yourself!
I'm sorry for the lack of photos, you can't exactly photograph an electrical current...
Parts list is explained further in the 'ible where I show you how to make this neat machine yourself.
Move on for the full experience!
**Before you comment and say "This is not ANTI-GRAVITY" please read the following:
Anti = Against, Opposed to, Prejudicial to, Preventing, Counteracting, or Mitigating.
Gravity = the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.
Anti in short is Opposed to.
Gravity in short is a downwards force.
Anti-Gravity is a term used for an object that is Opposed to a downward force (thus slowing down gravity).
Step 1: The what, when, where and why of eddy currents
"Eddy currents (also called Foucault currents) are circular electric currents induced within conductors by a changing magnetic field in the conductor, due to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field." ~Quote from wiki~
My dad has taught me to question everything with five simple words; Who, What, When, Where and Why?
Using this principle lets briefly explain eddy currents.
Who: Francois Arago
What: Eddy Current
Where:Beginning in 1933, in Germany, while working for the
Kaiser-Wilhelm-Institute, Professor Friedrich Forster adapted eddy current technology to industrial use, developing instruments for measuring conductivity and for sorting mixed-up ferrous components.
Why: To develop an instrument for measuring conductivity and for sorting mixed-up ferrous components.
So there you have it, the "who, what, where and Why" of eddy currents.
Now move on to the next step for my explanation of these wondrous marvels!
Step 2: My explanation.
So from what I understand, eddy currents are the following:
When a strong magnet passes through a tube of non-ferric metal (meaning the magnet won't stick) but this metal is conductive (i.e. copper, aluminium and brass).
When the magnet passes though the conductive-non-ferric material it creates electricity.
This electricity occurs in invisible waves that separate at the middle of the magnet, half going up and half going down.
The half of the currents that go down the tube ahead of the magnet loop back around and in the end they go up too.
In turn, the down-up currents push the magnet back up the tube thus making it fall at an extremely slow rate.
When the electrical currents push the magnet back up the tube the magnet can take over 20X the time to fall to the ground as a normal object.
The tube wall size also makes a difference, the thicker the wall - the slower the fall!
We have used a 3mm walled alloy tube and it took 20X longer to fall through the tube!
Eddy currents can also work if you drop a strong magnet onto a slab of conductive but non-ferric material, the magnet falls at high speed and then when it approaches the slab it slows right down and lands quite softly.
If you don't understand any of this please PM me and I will try to help.
Lets move on to where you can make your own eddy currents!
Step 3: The gear I'm using.
Here is a step dedicated to the gear I used.
I had a 30cm (1') (12") tube of aluminium.
I also had 1.5cm Neodymium magnet.
The third photo shows the time to drop, less than one second out of the tube and three seconds through the tube! 3 times longer with the eddy currents!
The next step will tell you how to set the effect up!
Step 4: D.I.Y. (Do It Yourself) Eddy currents.
Here's how to make eddy currents in your own home.
You will need either a neodymium or strontium magnet of a decent size.
You will also need a conductive but non-ferric material (preferably a tube).
Now you have to make sure the magnet will fit in the tube without touching the edges, there should be about a millimeter around the edges of the magnet.
Now with the end of the tube over a soft landing (rag, couch, bed, mattress, pillow or any other soft thing) you can drop the magnet through the tube - BUT - First you should drop it outside of the tube to test the difference!
You should notice the magnet moves much much slower through the tube and you can even drop marbles down the tube to eliminate the displacement theory.
Now that you have experienced your own eddy currents, please sign into Instructables (for new members, sign up) and cast a vote my way for the science contest 2015!
Thanks for reading, If you know anyone that might have a possibility of interest in this topic please send them the link!
I have now added a video to this 'ible, Many thanks to : BWRUSSELL for providing me with the URL so I could embed my video.