Browse Items (54 total)

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These glass spheres were used to contain gases such as iodine, bromine, and hypo-nitrous acid in order to study their light-absorption properties, i.e. their absorption spectra. Light shown on the cell passed through the glass and was absorbed by the…

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The three prisms hanging from the brass stand may be folded up in pairs to demonstrate achromatism (no color separation) or constant deviation (no color dependence of the angle of minimum bending of light.) These were made by Lerebours et Secretan of…

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An ammeter is a device for measuring electric current. The analog ammeter is constructed so as to pass only a small (but known) fraction of the current to be measured through the meter movement that deflects the needle. This allows a very sensitive…

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Analytical balances are accurate and precise instruments for weighing chemical samples. They require a dust-free and draft-free location on a solid bench that is free of vibrations. The samples must be measured at room temperature to prevent natural…

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Lightning is the ultimate arc lamp, and so Benjamin Franklin's 1752 experiment of drawing electricity from the clouds and jumping a spark is perhaps the first arc lamp. In 1801 Humphry Davy observed the brilliant spark obtained when the connection…

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The simplest type of balance, the equal-arm, or beam, balance, is an application of a lever. A uniform bar, the beam, is suspended at its exact center on a knife-edge set at right angles to it. The point of support is called the fulcrum. Two pans of…

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This is a device used to demonstrate the effect of atmospheric pressure. A glass vessel with openings at the bottom and top has its large top opening covered by a piece of animal bladder that is tied to seal it around its edges. As air is pumped from…

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Chemists, and other people who do careful weighings, know that we live at the bottom of a sea of air, and that a buoyant force equal to the weight of the air displaced by our bodies acts upward on us. Alas, the density of air is small, and the…

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When the large center disk, made of non-conducting material with metallic strips attached, was turned using a hand crank, fixed metallic brushes rubbed against the metallic strips causing them to become charged. The charge was drawn off and collected…

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A mathematical instrument for laying down and measuring angles on paper, used in drawing or plotting.

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A current balance measures the force of repulsion between two wires, each carrying an electric current. An upper wire is fixed in place, and the wire directly below it is free to move. The currents are adjusted so that the electrical attractive force…

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A five decade variable resistor made by Max Kohl of Chemnitz. The 0.1 and 1 ohm resistors are slide wires along the front and back of the top, and the three upper ranges use coils of low-temperature coefficient resistance wire (probably constantan).…

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NOT YET LOCATED. When two wires made of different metals are connected to make a loop, and the two junctions between the wires are held at different temperatures, a voltage is produced and electrical current can be detected with a sensitive current…

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The basic discharger is simply a conductor used to discharge a Leiden jar. The two arms are spread apart at the hinged joint, and the insulated handle prevents the operator from receiving a shock as the knobs are touched against the outer foil and…

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This picture should be rotated 90 degrees clockwise to show how the instrument was actually used. This kinetoscope was manufactured by Edison Mfg, Co, Orange, N.J., USA. around 1902. Continuous 35mm film wrapped around the reel, and turning the crank…

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The label of this electric motor notes that it is a 1/6 HP, 130 Volt motor made by the Crocker Wheeler Motor Company of New York. The patent dates are May 5 and September 22, 1891.

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In the nineteenth century almost all power supplies were direct current (DC). In order to step voltage up or down, the direct current had to be converted to alternating current (AC), stepped using transformers, and then converted back to DC. The…

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This is a demonstration device showing two aspects of electric charge. When the conducting sphere atop the vertical stand is charged (e.g. by using a Leyden jar) the horizontal pinwheel device at the top begins to spin as charge is leaked from its…

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This picture shows the electrical experimentation room in Reid Hall around 1900. The tangent galvanometer visible in the picture above had been moved and can be seen at the right. Just to the left of it is the Kelvin current balance still in the…

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"The “Fountain in Vacuo” is a perfectly delightful and entertaining 19th century demonstration that is never done today. Volume 1 of Pike’s Illustrated Catalogue of Optical, Mathematical and Philosophical Instruments (New York, 1856) describes…

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In 1844 Froment devised an electric motor that was one of the first used for industrial purposes. In his design, electromagnets are energized to attract iron bars mounted on a revolving cage. Once the iron bar is level with the electromagnet, the…

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NOT YET LOCATED. The term “galvanometer” is in current use, naming an instrument which indicates the strength of an electric current. The Galvanoscope is an earlier instrument, which shows the presence of the current but gives only a rough…

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Glass, when stressed, shows the property of double refraction: light of differing polarization directions bends differently passing through the glass. When placed between crossed polarizers , bands of color may be seen, with the spacing of the bands…

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The heliostat takes light from the sun as it tracks across the sky, and redirects it in a fixed direction. To accomplish this, the light is reflected from a mirror that reproduces the motion of the sun, except at twice the rate. Although he did not…

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This apparatus is listed in the 1885 catalogue of Jules Duboscq of Paris as the “Grand Circle of MM. Jamin et Sénnarmont.” It was designed for the study of the laws of polarized light reflected from crystalline substances, from liquids and from…

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Kaleidoscopes operate on the principle of multiple reflection, where several mirrors are attached together. There are three rectangular lengthwise mirrors. Setting the mirrors at a 45 degree angle creates eight duplicate images of the objects, six at…

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Friedrich Wilhelm Georg Kohlrausch (1840-1910) was a professor of physics at Göttingen, Zürich, Würtzburg, Strasbourg and Berlin during his career. He wrote a widely-used book on methods of experimental physics, and developed improved measurement…

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The Leyden jar is the earliest form of the condenser or capacitor. The jar allowed the electric charge produced by an electrostatic machine (for instance) to be accumulated and stored for future use. The first jars were made independently in 1745 by…

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These light bulbs were manufactured around 1905. They can be dated by the construction of the filament.  To learn more about antique light bulbs, visit this link to the  SCHENECTADY MUSEUM.

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The Magdeburg hemispheres are a pair of large copper hemispheres with mating rims. When the rims were sealed with grease and the air was pumped out through the valve below the lower hemisphere, the lowered pressure within the sphere made it very…

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