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Mini Projects

Through this article you will be able to understand construction and working of electric generator and electric motor. Electric generators, about which you may have read many times in books, are very simple to construct and can be used as mini school project. Many other projects can also be made using this experiment which can be used in science fair and exhibitions at school level.

Working Principle of Electric Generator:

Metals, as you know, are very good conductor of electricity because they contain free electrons that transfer energy from one end to other. When a coil is kept in a changing/ fluctuating magnetic field, electric voltage/potential difference occurs across the coil. This difference in potential forces these free electrons in the wire. In simple words, change in magnetic field causes electric current in the coils kept in that magnetic field. After doing the project you will have better understanding of its working.

Working Principle of Electric Motor:

The construction of electric motor is same as electric generator. In this, alternating current (AC) is passed through the coils which rotate the magnet kept inside the coil. This rotating magnet turns the motor shaft.

Now let’s check out the construction and working of electric generator.

Materials Required:

Small cylindrical films roll can, metal rod (spokes), straw (for bush bearing), strong magnets, insulated copper coils, electric wires, one LED.

Steps of Construction of Electric generator:


Take the film roll can and make two holes at equal height as shown. Holes should me at equal heights and take proper care while making holes.


Use two cut straw pieces and insert them each in the holes. These straw pieces will serve as bush bearings for smooth motion of magnet inside the can.


Now insert the metallic spoke containing magnet inside these straw pieces, as shown in the figure. After inserting the metallic spoke, make sure the magnet spins freely on its axis. This freely moving magnet will create the fluctuating magnetic field to produce the voltage potential required for the motion of free electron, as mentioned in the working of electric generators above.


Now take the insulated copper coil and wind it around the film can, as shown. Make approximately 1000 turns. More the number of turns more will be the voltage produced.


Now at the two ends of the coil thus wounded, connect one LED with the help of electric wires. Make sure the connection is right and the circuit is complete. If the circuit is not complete, the free electrons will not move and hence no electric current.


Now to the end of metallic spoke, connect a turbine/wheel as shown. This will help in turning the magnets around the axis. This completes the construction of electric generator.

Working of electric generator:

Turning the turbine wheel around the axis causes the magnets to spin. This movement of magnets causes change in magnetic field. This produces electric voltage which generates the electric current through the coils. LED will glow intermittently because the current thus developed is alternating current (AC).

Electric generators are used to produce electricity that we use. Basic principle of working is same for all generators, only the method of turning the turbine wheel changes.

This electric generator project can be used in making various other school science projects also. Check out this space regularly to have more project ideas.

The project idea that we are about to discuss under Mechanical Engineering Project Idea can come handy to amaze your friends and family. You can use Archimedes Screw Pump Project to show your engineering skills and knowledge and flabbergast everyone around you. The project idea has rightly been kept under Fun with Projects category keeping in mind the difficulty level of the project.



Archimedes screw pump works on a very useful concept in Mechanical Engineering known as Archimedes Screw pump. The pump is very simple to make and is used to transfer water from low lying location to relatively high lying location.



Archimedes Screw pump is a machine historically used as a method to transfer water from a low lying water body into irrigation lands and ditches. The device was designed by Archimedes in 3rd century BC to get rid of the water leaked into the ship. The method is so effective that it is still used in many modern mechanical engineering applications as well.

What is Archimedes Screw Pump?

Before getting into the project let us through some light on exactly what the device is. The screw pump in its simplest form consists of a screw embedded inside a hollow pipe with the help of a shaft. When this shaft is turned either manually or by connecting it to some other aid like windmill, the bottom end scoops up water from low lying location. This water slides up the spiral tube and pours out from top of the tube.

Materials Required:

  • PVC pipe
  • Clear tubing
  • Sticky tape
  • Scissors
  • Two bowls

How to Make Archimedes Screw Pump:


  • Using sticky tape wrap clear tubing around PVC pipe leaving some part of the tubing hanging free at both the ends of the PVC pipes as shown in the figure below.
  • Wrap the tubing carefully around the PVC pipe in regular interval and pin it at both ends with the help of sticky tapes.
  • There should be around 1/4 inch of tubing hanging at both the ends of the pipe where it has been taped.
  • The starting section of tubing will scoop the water into the tubing and end section will pour the water out.
  • Wrapping the tubing at regular intervals will give the period of tubing for calculations if required.

With this the basic set-up of screw pump is ready for the trick you are about to perform. Now lets set the two locations to transport water from lower to higher region. You can add color to the water to have track of water going through the tubing.


  • Place two bowls keeping some difference in slope between them. It can be done by keeping one bowl at relatively higher position than the other.
  • Now place the Archimedes screw pump across the two bowls as shown.
  • Make sure that the hanging part of the wrapped tubing is inside bowls.

Now lets see how the screw pump works.

Working of Archimedes Screw Pump:

When the screw is turned, water gets scooped into the tubing hanging out of the PVC pipe. As the screw is turned, water travels from lower bowl through tubing. Make sure the water does not fall back by adjusting the slope. Turn the screw several time to make sure water is traveling through the tubing. You can also vary turning speed to see how fast water climbs up.

Once you are sure about the technique, speed and slope of screw, you can go and make the trick work in front of your friends and showcase your talent.