Science‎ > ‎

Making a magnet

posted Feb 2, 2015, 2:00 AM by ranmini@charliesresearch.com   [ updated Jul 12, 2016, 1:53 PM by Upali Salpadoru ]


Fig.1. Look ! Pins getting attracted.


We get fascinated by magnets.  

There are magnets in our pencil boxes. There are magnetic pictures on fridges etc. Some students tend to think they are a kind of a substance.  

Magnets are mostly made from iron.

In order to make a magnet, what you need will be a piece of iron, (even a nail would do,) a piece of plastic covered copper wire  and a torch cell.

A wire wound in this manner is called a coil. For the piece of iron to get magnetized the electric current must go round and round many times. The more turns you have merrier it will be. As the wires are insulated they may even touch, or even overlap. If it is difficult to hold the ends of the wires touching the cell you may use a thick rubber band or clasp them in some other manner.
                 To find out whether your magnet is really working you can bring  pins, clips and nails near the piece of iron.  If you allow the current to pass for a long time the cell will soon run down.  Pulling one wire out of the rubber band can work as a switch to stop the current.

More Activities.


                Activity 1.     What substances (or objects)  get attracted to a magnet?

   You can bring various substances near a magnet and see how they get attracted .  If they get attracted very quickly give them an A.  If the attraction is mild give them a B.  If there is no attraction give a C, If they get pushed out give them an X
A chart like this can be used to record the results.

Object or    Substance

                                                    Result

Strong attraction

Mild attraction

No attraction

Repulsion

Iron or steel blades

 

 

 

 

Copper wire

 

 

 

 

     A few others:- Aluminium,Gold jewelery,Various coins,Another magnet

                             Activity  2       

                 Where will this magnet have the strongest pulling force?
                 To find an answer to this you can attach pins or clips at different places along the magnet.  The method is shown in this diagram.  What place or places in the magnet can hold the highest number of pins?

                           

  Fig. 2.   An experiment to find out the points having a high pulling force.

According to the diagram right hand side edge exerts the highest pulling force.  It is pilling three clips. This is not what may happen. You will have to do the experiment and find out the place or places having the strongest pull.

Activity 3   The effect of changing the core inside the coil
                           
For this activity, you have to wind the coil around a plastic tube or a card board cylinder.


Fig.3 A method to change the core.

Now insert wires or rods  of different materials into the core.  Instead of a solid iron rod you may even use a number of thin iron wires. Then find out which will create the most powerful magnetic field.. Magnetic force can be judged by the number of pins it can attract.  Another way to test the strength of the magnet is to bring it near a direction finding compass


Fig.4  The N of the needle will show a deflection in a horizontal magnetic field.




Fig.5. Pocket compasses aligning according to magnetic lines of force.

Magnetic lines are indicated by iron filings.

Comments