It is not everyday that young students discover a new law of nature on their own. The law the students will discover in this activity is not new to science, of course, but it may be new to them. The discovery process that the students undergo in this activity is bound to be both emotionally and intellectually intriguing.
The didactic principle guiding the activity is that as they work through it, the students are quite unaware that they are progressing towards the discovery of a new law of nature. They are working merely to solve a challenging riddle. In order to solve it they need to build an original measuring instrument. Only at the end of the activity, during the discussion about the results and conclusions of the experiment, will the students discover that not only is it possible to formulate a law from these results, but that this law was formulated by one of the greatest physicists of the 17th century - Robert Hooke, a physicist of the same generation as Newton.
The law the students will discover formulates the degree of extension of springs and other elastic objects as dependent on the force (weight) operating on them. This law stating that the extension of a spring is directly proportional to the force applied to it, is used in many technological tools to this very day. This is an unexpected achievement from such an innocent-looking activity.
To prepare for your lesson, you will find the following resources useful: