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Simple School Projects

Updated on December 19, 2012

Concept Oriented Education

The sole aim of this and a series of blogs is to impart quality and concept oriented education to children. In today's world, parents have to be well educated and are bound to spend quality time on their children for the benefit of their future. Most parents lack in time in paying attention for various reasons. To ease their job, we've planned to release a list of projects for them to help their children. These projects seem to be very simple but informative. Honestly, the projects were collections from various sources but presented in our own style. So, thanks for all sources. The projects are based on items that we use in our daily life. Hope, this would help children develop their skills in science. The list of projects is not limited to the following but will increase in course of time. To start with, the first and simple project is

How does a Ball Pen work?

We all know and seen a ball pen or a ball point pen. We would've used it in our daily life. We're not going to see the detailed use of it here, as the focus would be only on the concept.

Fine, before we start, keep a ball pen with you that you might not be using for the moment. That is, an exhausted one. You're going to analyze how it works. So, before throwing the used one, let's us see the important parts and the concept behind.

Step 1 - Important parts and Assembly - Refer Video 1.

  • Steel or Brass Ball
  • Spring
  • Cam & a follower like arrangement.
  • Ink reservoir tube
  • Push button to push the ball point in and out


  • Push button is attached to a follower ( a small rod ), the follower is attached to a tube containing ink in it. At the end of the ink reservoir tube a ball is set. The ink reservoir tube has a spring in it. See the video below. The whole arrangement is kept in a casing.

Working Mechanism

The tip of the pen has the ball on a socket. The ball on the other hand will receive ink from the ink reservoir tube. The ink, which is viscous in nature, acts as an lubricant for the ball to move. The ink is forced down by gravity. The rolling mechanism allows the ink to flow through the ball and to write on the paper. The tolerance between the ball and reservoir tube helps in two ways; one to get the ink on gravity and the second to allow air so that the ink does not dry.

When the push button is pressed down, it works on the spring pressuring the ink reservoir tube move down. Here, there will be tiny pits and teeth that help in locking mechanism. When the push button is retracted, the cam-follower mechanism is applied and the pen gets unlocked.

Ball Pen Assembly

Cam and Follower Mechanism

Retractable Ball Pen

Step 2 - Clicking Mechanism

What is a cam and a follower? What is its mechanism?

Cam is flat that has an unusual shape. It will be in contact with a rod called Follower. The movement of cam and follower resembles simple uniform motion as in pendulum. Follower moves in a particular direction based on the rotation of cam. The locking and unlocking of pen is done by the cam-follower mechanism. The video 2 attached to it explains the working principle of cam and a follower.


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