We learn in the Physics books that the Period - the time for one complete round-trip - of a Simple Pendulum - is given by this mathematics: T = 2piSqrt(L/g) This means that the time of oscillation is governed by the squareroot of the length and by g - that is - where on the Earth or on the Moon - do we clock it. ANY body can oscillate as a pendulum - say a rod - and this we call a Physical Pendulum. Every Physical Pendulum has an Equivalent Simple Pendulum - that is, a simple pendulum which keeps in phase with the motion of the Physical Pendulum. A loaded spring also oscillates with a Period governed by how stiff the spring is and what the load on it is. Oscillating bodies can be coupled with other oscillating bodies - that is - connected with them.
A- We show three Simple Pendulums of lengths 10, 40, 90 cm. We clock equal numbers of oscillations. The times come out to be very interest¬ing! In the ratio of 1:2:3.
B - Since the "formula" for the period of a simple pendulum does NOT involve the mass of the bob we show several pendulums with bobs of different size and mass. C - We show in turn - a prismatic rod; a hoop; a disk. These all execute oscillatory motion as physical pendulums., The rod has special enchant¬ing properties: It has the same period at a point 2/3 its length as it does at its very end! And this tells us why a bat stings the hand sometimes!
D - We show an array of loaded springs - alone and coupled. The period of a loaded spring is given mathematically by T = 2piSqrt(M/k) where M is the load on the spring and k is its modulus - that is - a number which tells us how stiff it is. A special interesting problem arises: If a spring of length L has a modulus k - what is the modulus of half such a spring? It turns out to be 2k -which is very exciting to know. The genius Robert Hooke - who was a contemporary of Isaac Newton - discovered the Law of the Spring. He wrote it as an anagram in this way: ceiiinosssttuv And why did he write it this way? Because he was afraid Newton would steal it! The anagram reads Ut tensio sic vis As the extension so the force.
Demonstrations in Physics was an educational science series produced in Australia by ABC Television in 1969. The series was hosted by American scientist Julius Sumner Miller, who demonstrated experiments involving various disciplines in the world of physics. The series was also released in the United States under the title Science Demonstrations.
This program was a series of 45 shows (approximately 15 minutes each) on various topics in physics, organized into 3 units: Mechanics; Heat and Temperature / Toys; and Waves and Sound / Electricity and Magnetism.