"In <em>optics</em>, a deviation in the rays of light when unequally refracted by a lens or reflected by a mirror, so that they do not converge and meet in a point or focus, but separate, forming an indistinct image of the object, or an indistinct image with prismatically colored edges."-Wright, 1902

Aberration

"In optics, a deviation in the rays of light when unequally refracted by a lens or reflected…

"That point in which a right line drawn from the eye parallel to another given right line cuts the picture of plane."-Whitney, 1902

Accidental Point

"That point in which a right line drawn from the eye parallel to another given right line cuts the picture…

This barometer depends upon the changes in form of a think metallic vessel partially exhausted of air, as the atmospheric pressure varies.

Aneroid Barometer

This barometer depends upon the changes in form of a think metallic vessel partially exhausted of air,…

This figure represents an apparatus frequently employed for illustrating some of the consequences of Torricelli's Theorem.

Apparatus for verifying Torricelli's Theorem

This figure represents an apparatus frequently employed for illustrating some of the consequences of…

Aristotle was a Greek philosopher, a student of Plato and teacher of Alexander the Great. He wrote on many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, politics, government, ethics, biology and zoology.

Statue of Aristotle

Aristotle was a Greek philosopher, a student of Plato and teacher of Alexander the Great. He wrote on…

A simple apparatus called the arithmetical lever for illustrating the laws of parallel forces.

Composition of Parallel Forces

A simple apparatus called the arithmetical lever for illustrating the laws of parallel forces.

Atwood's machine illustrates the effects of force in producing motion.

Atwood's Machine

Atwood's machine illustrates the effects of force in producing motion.

This experiment illustrates the law of action and reaction, which asserts that momentum cannot be imparted to any body without equal and opposite momentum being imparted to some other body.

Backward Movement of Discharging Vessel

This experiment illustrates the law of action and reaction, which asserts that momentum cannot be imparted…

"A representation of a common form of the delicate balances employed in physical and chemical researches. the beam is constructed so as to combine lightness with strength, and rests by a fine knife-edge on an agate plane. It is surmounted by a weight moving on a screw, so that the sensibility may be increased or diminished, according as weight is raised or depressed." &mdash; Chambers' Encyclopedia, 1875

Balance

"A representation of a common form of the delicate balances employed in physical and chemical researches.…

In the common balance there is a stiff piece of metal called the beam, which turns about the sharp edge of a steel wedge forming part of the beam. The scale pans rest upon the hooks of the wedges.

Balance

In the common balance there is a stiff piece of metal called the beam, which turns about the sharp edge…

A balance of great delicacy with the glass case that contains it.

Balance for Purposes of Accuracy

A balance of great delicacy with the glass case that contains it.

The car in which the aeronauts sit is usually made of wicker-work of whalebone. It is sustained by cords attached to a network covering the entire upper half of the balloon.

Balloon with Car and Parachute

The car in which the aeronauts sit is usually made of wicker-work of whalebone. It is sustained by cords…

An instrument used for indicating changes in atmospheric pressure.

Baroscope

An instrument used for indicating changes in atmospheric pressure.

A general view of the air-pump apparatus formed by Bianchi.

Bianchi's Air-pump

A general view of the air-pump apparatus formed by Bianchi.

This apparatus is used to prove Boyle's Law which describes the relationship between the product pressure and volume within a closed system as constant when temperature remains at a fixed measure; both entities remain inversely proportional.

Proof of Boyle's Law for Expanding Air

This apparatus is used to prove Boyle's Law which describes the relationship between the product pressure…

(1627-1691) An Irish natural philosopher noted for his physics and chemistry. Dr. Boyle was known for <em>The Sceptical Chymist</em>.

Robert Boyle

(1627-1691) An Irish natural philosopher noted for his physics and chemistry. Dr. Boyle was known for…

A Cartesian diver or Cartesian devil is a classic science experiment, named for Ren&eacute; Descartes, which demonstrates the principle of buoyancy and the ideal gas law.

Cartesian Diver

A Cartesian diver or Cartesian devil is a classic science experiment, named for René Descartes,…

"When a vessel containing water is whirled rapidly round, why does not the water fall out when the vessel is upside down? Because the centrifugal force, tending to make the water fly from the center, overcomes or balances the attraction of gravitation, which tends to cause the water to fall out." &mdash; Wells, 1857

Centrifugal Force

"When a vessel containing water is whirled rapidly round, why does not the water fall out when the vessel…

This figure represents a small centrifugal pump as mounted for use. The largest class of centrifugal pumps are usually immersed in the water to be pumped, and revolve horizontally.

Centrifugal pump

This figure represents a small centrifugal pump as mounted for use. The largest class of centrifugal…

This instrument consists of a bent tube closed at one end and containing within the space a quantity of air which is cut off from external communication by a column of mercury.

Compressed Air Manometer

This instrument consists of a bent tube closed at one end and containing within the space a quantity…

A French physicist and chemist famous for her work on radioactivity. She was the first person honored with two Nobel prizes, in physics and chemisty.

Marie Curie

A French physicist and chemist famous for her work on radioactivity. She was the first person honored…

"To avoid friction and heat, the piston is not in contact with the cylinder in which it works."

Deleuil's Air-pump

"To avoid friction and heat, the piston is not in contact with the cylinder in which it works."

Double acting pumps use both sides of the piston to pump fluid.

Double-action pump

Double acting pumps use both sides of the piston to pump fluid.

Two racks carry the pistons and work with the pinion. The pinion is turned by a double-handed lever, which is moved alternately in opposite directions.

Double-barrelled Air-pump

Two racks carry the pistons and work with the pinion. The pinion is turned by a double-handed lever,…

"A drill to which a steady momentum is imparted by means of a fly-wheel having a reciprocating motion like that of the balance-wheel of a watch." -Whitney, 1911

Fly Drill

"A drill to which a steady momentum is imparted by means of a fly-wheel having a reciprocating motion…

An instrument used to measure the force of the intermingling of two liquids of different densities, in close juxtaposition, but separated by a thin membranous tissue.

Endosmometer

An instrument used to measure the force of the intermingling of two liquids of different densities,…

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

Deadbeat Escapement

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

Recoiling Escapement

A piece in clocks and watches that converts rotational motion into oscillation, as in a pendulum.

An experiment using a balloon and air-pump to demonstrate the expansibility of gases.

Expansibility of Gases

An experiment using a balloon and air-pump to demonstrate the expansibility of gases.

The pressure on the bottom of a vessel containing liquid is not affected by the breadth or narrowness of the upper part of the vessel.

Experiment of Pascal's Values

The pressure on the bottom of a vessel containing liquid is not affected by the breadth or narrowness…

The illustration of putting lenses in front of the eye. The focal point of the image is reflected into the eye. The focal point in the lens will end past the eye, creating a blurry image.

Optical Position and Size of Image Through Lens in Front of Eye

The illustration of putting lenses in front of the eye. The focal point of the image is reflected into…

(1791-1867) British scientist, chemist, physicist, and philosopher who greatly contributed to the fields of electromagnetism and electrochemistry.

Michael Faraday

(1791-1867) British scientist, chemist, physicist, and philosopher who greatly contributed to the fields…

The ordinary fire-engine is formed by the union of two forcing-pumps which play into a common reservoir, containing in its upper portion air compressed by the working of the engine.

Fire engine pump

The ordinary fire-engine is formed by the union of two forcing-pumps which play into a common reservoir,…

In the first order of levers, the fulcrum is between the power and the weight.

First Orders of Lever

In the first order of levers, the fulcrum is between the power and the weight.

The forcing pump consists of a pump-barrel dipping into water, and having at the bottom a valve opening upward.

Forcing-pump

The forcing pump consists of a pump-barrel dipping into water, and having at the bottom a valve opening…

This apparatus consists of a bell-shaped vessel of glass, the base of which is pierced by a tube fitted with a stop-cock which enables us to exhaust the vessel of air.

Fountain in Vacuo

This apparatus consists of a bell-shaped vessel of glass, the base of which is pierced by a tube fitted…

"In mechanics, the point of rest about which a lever turns in lifting a body; also, a prop or support for a lever at this point. F, Fulcrum; L, lever." -Whitney, 1911

Man with Lever and Fulcrum

"In mechanics, the point of rest about which a lever turns in lifting a body; also, a prop or support…

An apparatus for verifying the parallelogram of forces. This method is used in physics for determining the force of vectors.

Gravesande's Apparatus

An apparatus for verifying the parallelogram of forces. This method is used in physics for determining…

"Gyroscope. Gyroscopic top, an instrument consisting of a heavy fly-wheel revolving about an axis one point of which is fixed, but which is otherwise free to move in any way." -Whitney, 1911

Gyroscope

"Gyroscope. Gyroscopic top, an instrument consisting of a heavy fly-wheel revolving about an axis one…

"Foucault's Gyroscope. GYROSCOPE. An instrument consisting of a fly-wheel, the axis of which can turn freely in any direction, designed to illustrate the dynamics of rotating bodies." -Whitney, 1911

Foucault's Gyroscope

"Foucault's Gyroscope. GYROSCOPE. An instrument consisting of a fly-wheel, the axis of which can turn…

"Gyrostat. An instrument for illustrating the dynamics of rotation, composed of a box or case having a sharp bearing-edge in the form of a regular polygon, and containing a fly-wheel having its center and its direction of rotation in the plane of the bearing-edge." -Whitney, 1911

Gyrostat

"Gyrostat. An instrument for illustrating the dynamics of rotation, composed of a box or case having…

A hand holding a pointed weight suspended from a string.

Hand holding weight

A hand holding a pointed weight suspended from a string.

A machine designed to suppress the dead space which limits the efficiency of ordinary air-pumps.

Kravogl's Air-pump

A machine designed to suppress the dead space which limits the efficiency of ordinary air-pumps.

This apparatus illustrates the principle stating that liquids tend to find their own level.

Vessels in Communication

This apparatus illustrates the principle stating that liquids tend to find their own level.

"The Atwood machine consists of a wheel or pulley, R, over the grooved edge of which are balanced two equal weights suspended by a long silk thread which is both light and strong. The axle of this wheel is preferably supported upon the circumfrences of four friction wheels, r, r, r', r', for greater delicacy of motion. As the thread is so light that its weight may be disregarded, it is evident that the weights will be in equilibrium whatever their position." &mdash; Avery, 1895

Atwood Machine

"The Atwood machine consists of a wheel or pulley, R, over the grooved edge of which are balanced two…

A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted, either by contact or by other means.

Magnet

A bar or mass of steel or iron to which the peculiar properties of the loadstone have been imparted,…

This is an apparatus employed to obtain a uniform flow of water. The device provides a constant pressure delivering a constant rate of flow.

Mariotte's Bottle

This is an apparatus employed to obtain a uniform flow of water. The device provides a constant pressure…

When gases of different densities are inclosed in the same space an intimate mixture takes place, so that each gas becomes uniformly diffused throughout the entire space.

Mixture of Gases

When gases of different densities are inclosed in the same space an intimate mixture takes place, so…

An illustration of Sir Isaac Newton sitting on the ground being hit by an apple falling out of a tree and discovering the law of gravity.

Isaac Newton Discovering Gravity

An illustration of Sir Isaac Newton sitting on the ground being hit by an apple falling out of a tree…

An illustration of the position and the size of the image viewed by the eye. The eye approximates the the height of the image. The image's height is the hypotenuse of the triangle, creating an angle with the eye. This image is then reflected upside down in the eye.

Position and Size of Image for Eye Optics

An illustration of the position and the size of the image viewed by the eye. The eye approximates the…

"If y be the object the image appears to a normal eye situated behind the system L with passive accommodation at a very great distance under the angle w'. Since H' P&#61; F O, &#61; y, from the focal length of the simple microscope is the image side focal length." &mdash;Encyclopaedia Britannica, 1910

Optical Position and Size of Image Through Magnifying Glasses

"If y be the object the image appears to a normal eye situated behind the system L with passive accommodation…

"The intersection of the principal rays in this case lies in the middle of the entrance pupil or of the exit pupil. By head and eye motion the various parts of the whole field can be viewed one after another." &mdash;Encyclopaedia Britannica, 1910

Optical Position of Diaphragms using Lens

"The intersection of the principal rays in this case lies in the middle of the entrance pupil or of…

"In the diagram, let AB and AC represent two forces acting upon the point, A. Draw the two dotted lines to complete the parallelogram." &mdash; Avery, 1895

Parallelogram

"In the diagram, let AB and AC represent two forces acting upon the point, A. Draw the two dotted lines…

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in the experimental demonstration of the earth upon its axis. The chief function of the wheel-work of a clock is to register the number of vibrations of the pendulum. If the clock gains time, the pendulum is lengthened by lowering the bob, if it loses time, the pendulum is shortened by raising the bob." &mdash; Avery, 1895

Pendulum

"A pendulum has a strong tendency to maintain its plane of oscillation, a fact that has been used in…

"When the pendulum hands at rest in a vertical position, as Pa, it has no energy at all. Considered as a mass of matter seperate from the earth; it certainly has potential energy; but considered as a pendulum, it has not." &mdash; Avery, 1895

Path of a pendulum

"When the pendulum hands at rest in a vertical position, as Pa, it has no energy at all. Considered…

A device used for demonstrating the elastic properties of materials.

Physics demonstration

A device used for demonstrating the elastic properties of materials.

A pipette is a laboratory instrument used for transporting a volume of liquid. If one end is closed with a finger, the efflux of the liquid will cease immediately.

Pipette

A pipette is a laboratory instrument used for transporting a volume of liquid. If one end is closed…

"To avoid friction and heat, the piston is not in contact with the cylinder in which it works."

Piston and Barrel of Deleuil's Air-pump

"To avoid friction and heat, the piston is not in contact with the cylinder in which it works."

An experimental verification of the Principle of Archimedes.

Experimental Verification of Principle of Archimedes

An experimental verification of the Principle of Archimedes.

A pulley, when fixed in such a way that it can only turn about a fixed axis, confers no mechanical advantage.

Pulley System

A pulley, when fixed in such a way that it can only turn about a fixed axis, confers no mechanical advantage.