
Lecture Description
MATTER as we know it exists in three familiar "states": Solid-Liquid-Gas. Liquids have strange and wonderful properties one of these being incompressibiiity - they cannot be squeezed together very much. We show this enchanting business in a number of DEMONSTRATIONS.
A - PASCAL'S PARADOX: Three glass vessels have different shapes but the same base. We fill these to the same depth with water. And very strangely they have the same pressure on the bottom and the same force on the bottom. Pressure we define as a Force per unit area - that is
P = F/A.
B - The Hydraulic Press utilizes the dramatic property of the incompressibiiity of liquids and Pascal's Principle which says: A force communicated to a liquid is "felt" without loss in all parts of the liquid. The press is worked by a lever so this machine is a Compound Machine and it has enormous Mechanical Advantage.
C - A hypodermic needle has a very tiny point - a point of small area. If we push the piston with the thumb with a force say of ONE pound and the point has an area of ONE THOUSANDTH of a square inch we have at the point end a PRESSURE of ONE THOUSAND POUNDS PER SQUARE INCH. No wonder the needle goes in!
D - We show an array of demonstrations of a simple ordinary sort which point up the beauty of these properties of liquids:
1 - We squeeze a flask equipped with a glass tube; the liquid goes UP
and it goes DOWN. The glass is highly ELASTIC and the water is highly incompressible.
2 - The Cartesian Diver: The water is incompressible; the air IN the
Diver very compressible.
3 - A flask filled COMPLETELY with water can be broken apart by a
sharp blow on the stopper. WHY? The water is incompressible.
4 - A flask filled COMPLETELY with water can be used as a hammer
to drive nails. WHY? The water is highly incompressible.
E - A tin can is filled with water. The can has a TINY hole in the side near the bottom. With the stopper IN the water does not run out! Pull out the stopper and the water runs out! What holds the water IN? Answer: Atmospheric Pressure.
F - A U-Tube has mercury in it to a certain level. We add water to one arm. The mercury falls in that arm and rises in the other. A measure of the mercury and water columns reveals a wonderful thing: The ratio comes out to be 13.6 - which is the specific gravity of mercury.
We show a picture of Blaise Pascal - that genius of the 17th century who lived a very short life (1623-1662) but one filled with drama. He died as is said -with seven-fold immortality: as a mathematician - a physicist - an inventor -chief creator of his nation's great prose - a theologian - a philosopher - and a fanatic. His sister wrote a biography of him.
Course Index
- The Idea of the Center of Gravity
- Newton's First Law of Motion: Inertia
- Newton's Second Law of Motion: The Elevator Problem
- Newton's Third Law of Motion: Momentum
- Energy and Momentum
- Concerning Falling Bodies & Projectiles
- The Simple Pendulum and Other Oscillating Things
- Adventures with Bernoulli: Bernoulli's Principle
- Soap Bubbles and Soap Films
- Atmospheric Pressure
- Centrifugal Force and Other Strange Matters
- The Strange Behavior of Rolling Things
- Archimedes' Principle
- Pascal's Principle: The Properties of Liquids
- Levers, Inclines Planes, Geared-wheels and Other Machines
- The Ideas of Heat and Temperature
- Thermometric Properties and Processes
- How to Produce Heat Energy
- Thermal Expansion of Stuff: Solids
- Thermal Expansion of Stuff: Gases & Liquids
- The Strange Thermal Behavior of Ice and Water
- Heat Energy Transfer by Conduction
- Heat Energy Transfer by Convection
- Heat Energy Transfer by Radiation
- Evaporation, Boiling, Freezing: A Dramatic Adventure
- Miscellaneous Adventures in Heat
- The Drama in Real Cold Stuff: Liquid Nitrogen
- The Physics of Toys: Mechanical
- The Physics of Toys: Acoustic and Thermal
- Waves: Kinds of Properties
- Sound Waves: Sources of Sound & Pitch and Frequency
- Vibrating Bars and Strings: The Phenomenon of Beats
- Resonance: Forced Vibrations
- Sounding Pipes
- Vibrating Rods and Plates
- Miscellaneous Adventures in Sound
- Electrostatic Phenomena: Foundations of Electricity
- Electrostatic Toys, Part 1
- Electrostatic Toys, Part 2
- Adventures with Electric Charges
- Adventures in Magnetism
- Ways to "Produce" Electricity
- Properties and Effects of Electric Currents
- Adventures in Electromagnetism
- Further Adventures in Electromagnetism
- Miscellaneous and Wondrous Things in E&M
Course Description
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.