th th Magnetism, balancing of forces (level 7 to 10 )

Magnetic Levitation activity will help us understand that:

If the gravitational force (weight) of a body is balanced with a force of repulsion due to magnets, the body will levitate (raise)

Be careful while using cutters to make slits on the rubber-sheet/cardboard base.

Content:

Key learning:

Safety:

Activity Procedure:

1www.life-lab.org

Magnetic LevitationMagnetic Levitation

1 2One more combination

Magnets A and B repel C; and all 3 are same planeMagnets E and D repel F; and all 3 are same plane

Another view

Magnets A and B repel C and all 3 magnets in same plane

Levitation with 3 magnets

Dimple

Another view

A

B

C

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The pencil is levitated in the air due to balancing of forces:

a.

b.

Try to rotate the pencil in a circular motion while it is in the levitated position. Observe what happens. Why the pencil does not

fall?

Maglev Trains are one of the classic examples of the application of magnetic levitation. The pole of the magnets on the rail and

train are arranged to repel each other. So, trains can move without physically touching the rails, saving huge losses due to friction. [1]The average speed of the Maglev train is 350 km/hr .

Summary:

Think :

Relate:

Currentin track

Train magnet

Guide magnet

Train

Rail

Guide magnets control propulsion

Reaction force Magnetic

repulsion

Magnetic repulsion

Weight(gravitational force)

Magnetic repulsion

The weight of the pencil and the 2 ring magnets C and F (acting downwards) = repulsive force by the 4 ring magnets A and B;

E and D (acting upwards).

The Reaction force from the CD piece balances the Repulsive force on the pencil by the magnets A and B in the forward

direction.

Alternatives:

References:

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[1] - http://en.wikipedia.org/wiki/Maglev

Design procedures and alternatives - http://www.arvindguptatoys.com/toys/levitation.html

Image source - Maglev Train

a. http://www.universetoday.com/61590/what-is-friction/

b. http://www.whatsonxiamen.com/news5690.html

Base and be replaced with a juice tetrapack.CD can be replaced with box lid.

Base magne ts can also be fitted in pencils

One more assembly variationMagnets fixed using plasticine/modeling clay

Old CD

6 Ring magnets17.5 mm OD, 7.5mm ID, 3mm thick. Cost Rs one per magnet