Objective :

To see Dia and Paramagnetism in action   

Introduction :

Magnets attract iron clips, pins, nails etc very strongly. This is because iron is a ferromagnetic material. There are certain materials in which large number of atoms/molecules are magnetically ordered making domains. These are ferromagnetically/antiferromagnetic or ferrimagnetic materials.

   In large number of materials, magnetic ordering is absent. In some materials, the individual atom/molecule/ions does not have a magnetic moment. Such materials are diamagnetic and are weakly repelled by magnets. In another class of materials, the individual entity has magnetic moment but they do not much interact with each other and do not form domains, such materials are called paramagnetic.

  While ferromagnetic materials ate strongly attracted to a magnet, the attraction or repulsion of a paramagnetic or a diamagnetic material is quite weak. That is why we do not see any effect of magnet on aluminum, copper, glass, plastic etc, In this experiment you will experience these forces and will classify some objects whether they are paramagnetic or diamagnetic.  

Keywords :

Magnetic moment, Diamagnetism, Paramagnetism, Ferromagnetism.

Equipment :

A plastic tub, thermocol piece, two test tubes, materials to be tested, a strong magnet, a long nail/screw to hold the magnet. 

Procedure:

Take some common household material like salt, sugar, water, oil etc. Some of these are in solid power form and some in liquid form. Use one of the test tubes for solids and other for liquids.

  1. Fill the tube with water up to say 3/4 of the height.
  2. Make a small hole in the thermocol piece and put a test tube in it so that the bottom 1/4 of the test tube is below the hole and the rest above the hole.
  3. Put it in the water btub and check that it floats with the test tube remaining vertical.
  4. Fill the material in the test tube up to about 3/4 part and make it float. Make it stay at rest in the middle of the tube . For liquids, you can use the syringe given.
  5. Put the magnet on the tip of the nail and hold the nail.
  6. Bring the magnet close to the test tube, the pole facing the material in the tube. Go closer to the test tube but short of touching it.
  7. See whether the test tube starts going away from the magnet or coming towards the magnet, Write whether the material is paramagnetic or diamagnetic in a nicely formatted table.

Discussion :

Thermocol piece has a great role in providing stability. The buoyancy force on the thermocol from the sides of the tube makes the tube stay in vertical stable equilibrium. Salt solution is conducting because of the ionic character of NaCl.

The frictional force between water and thermocol is quite small and that is very important as the force between the magnet and the para dia magnetic material is very weak. If water gets contaminated, friction may increase and you may not see the effect.

Acknowledgement :

First shown by Mr MS Marwaha at NWUPT-2011 with water melon.  BVN-IAPT Anveshika, Delhi demonstated in the present form in 2012.

Hazard :

None