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70 Cards in this Set
- Front
- Back
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Absolute humidity |
The actual mass or content of water in a measured volume of air. It is usually expressed in grams per cubic meter or pound a |
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Acoustics |
The science of sounds |
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Adhesive forces |
Attractive forces between two different kinds of molecules |
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Ammeter |
An instrument for measuring the strength of an electric current in terms of amperes. |
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Amorphous solids |
A solid, such as glass or margarine, in which the constituent atoms and molecules are arranged in a fashion that is not rigid. In contrast, the constituent particles of crystalline solids are more rigidly arranged. |
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Ampere |
The standard unit of measurement of electric current. |
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Archimedes principle |
States that when an object is submerged in a fluid, it will be buoyed up by a force equal to the weight of the fluid that is displaced by the object. |
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Atomic theory |
The concept that all matter is composed of submicroscopic atoms that are, in turn, composed of protons, electrons, and neutrons. A chemical element is identified by the number of protons in its atom. |
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Atoms |
The smallest division of an element that exhibits all the properties and characteristics of that element, including neutrons, electrons, and protons. The number of protons in the nucleus of every atom of a given element is the same and is called its atomic number. |
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Avogadro's number |
The number of particles (ie, atoms or molecules) in one mole of a particular substance. It has been determined to be approximately 6.02x1023 mole^1. |
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Boiling point |
The temperature at which a liquid begins to turn to gas. For water at 1 atm: 100° C, 212°F, or 373°K absolute. |
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Boltzmann universal gas constant |
A fundamental physics constant constant named for Ludwig Boltzmann, who determined its value as being equivalent to the ratio of the universal gas constant to Avogardo's number. It has a value of 1.380662x10^-23 joules per kelvin. |
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Buoyancy |
When an object us immersed in a fluid, it appears to weigh less than it does in air. |
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Celsius |
Temperature scale in which 0° is the freezing point of water and 100° is the boiling point of water at sea level. |
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Cohesive forces |
Attractive forces between like kinds of molecules. |
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Compounds |
A substance composed of two or more elements, chemically combined in definite proportions, that cannot be separated by physical means. |
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Condensation |
Change of state from gas to liquid, such as with water vapor condensation. |
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Critical point |
The critical temperature and the critical pressure of a substance. |
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Critical pressure |
The pressure above which a material cannot exist as a gas. |
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Critical temperature |
The temperature below which a material cannot exist as a gas. |
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Diffusion |
The physical process whereby atoms or molecules tend to move from an area of higher concentration or pressure to an area of lower concentration or pressure. |
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Dipole-dipole interactions |
The interaction of equal and opposite electrical charges. |
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Electricity and magnetism |
See Chapter 1 |
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Electromotive force (EMF) |
The electrical potential, or the ability if electric energy to perform work. Usually measured in joules per coulomb or volts. Any device, such as a storage battery, that converts some form if energy into electricity is a source of EMF. |
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Elements |
One of more than 100 primary, simple substances that cannot be broken down into any other substance by chemical means. Each atom of any element contains a specific number of protons in the nucleus and an equal number of electrons outside the nucleus. The nucleus contains a variable number of neutrons. An element with a disproportionate number of neutrons may be unstable, in which case the nucleus undergoes radioactive decay into a more stable elemental form. |
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Evaporation |
The process by which liquids change into the vapor state. This occurs because of changes in temperature, pressure, and vapor pressure gradients. |
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Fahrenheit |
A temperature scale in which the boiling point of water is 212 F and the freezing point of water is 32 F at sea level |
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Fluidic |
Referring to hydrodynamic principles used to direct gas flow through circuits, resulting in switching of flow directions and signal amplification. Also used in pressure-sensing and flow-sensing. |
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Freezing point |
The temperature at which a liquid becomes a solid. |
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Gravitational potential energy |
The potential energy an object can gain by falling, as a result of gravity. |
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Horsepower |
Common term for power; measure of the rate at which work is being performed. (P=W/t) |
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Hydrogen bonding |
The attractive force of compounds in which a hydrogen atom covalently linked to an electronegative element (e.g., oxygen, nitrogen, fluorine) has a large degree of positive character relative to the electronegative atom, thereby causing the compound to have a large dipole. |
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Hydrometer |
A device that determines the specific gravity or density if a liquid by comparing its weight with that of an equal volume of water. A calibrated, hollow, glass device is placed in the liquid being examined, and the depth to which the device settles in the liquid is noted. |
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Insulators |
A nonconducting substance that is a barrier to heat or electricity passage. |
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Joules |
A unit of energy or work in the meter-kilogram-second system. It is equivalent to 10^7 ergs or 1 W-second. |
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Kelvin |
An absolute temperature scale calculated in centigrade units from the point at which molecular activity apparently ceases (-273.15 C) . To convert Celsius degrees to Kelvin add 273.15 to the Celsius temp. |
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Kilowatt |
Unit of measure of electrical power (1000 W). |
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Kinetic energy |
The energy a body possesses by virtue of its motion. |
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Kinetic theory |
Theory that states that atoms and molecules that make up matter are in constant motion. |
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Latent heat |
The amount of heat needed for a substance to change its state of matter. |
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Macroshock |
A shock from an electric current of 1 mA or greater that is applied externally to the skin. |
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Mechanics |
The branch of physics dealing with the motion of material bodies and the phenomena of the action of forces on them |
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Melting point |
The temperature at which solids being to turn into liquids. |
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Microshock |
A shock from a usually imperceptible electrical current (<1mA) that is allowed to bypass the skin and follow a direct, low resistance pathway into the body. |
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Mixtures |
A substance composed of ingredients that are not chemically combined and do not necessarily occur in a fixed proportion. |
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Molecules |
The smallest unit that exhibits the properties of an element or compound. A molecule is composed of two or more covalently bonded atoms. |
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ohm |
A unit of measurement of electrical resistance. One ohm is the resistance of a conductor in which an electrical potential of 1 V produces a current of 1A. |
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Ohm's law |
V=I x R |
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optics |
A field of study that deals with the electromagnetic radiation of wavelengths that are shorter that radio wave but longer than X-rays. |
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Potential energy |
The energy a body possesses by virtue of its position. |
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Power |
A source of physical or mechanical force or energy. Force or energy that can be put to work. |
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Rankine |
The fourth temperature scale, used in the engineering sciences. |
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Relative humidity |
The ratio of actual to potential water vapor in a volume of gas (i.e., how much is present as opposed to how much could be present). |
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Resistors |
Passive electrical component that impedes the movement of electrons through an electrical circuit. |
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Semiconductors |
Materials with conductivity characteristics that are intermediaries between conductors and insulators. |
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Sublimation |
The direct transition of a substance from solid to the gas or vapor state. |
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Supercooled liquids |
An amorphous solid (e.g., margarine) |
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Systeme Internationale d Unites (SI) |
An internationally accepted scientific system of expressing length, mass and time in base units (IU) of meters, kilograms, and seconds, replacing the old centimeter-gram-second system (CGS). The SI system includes the ampere, Kelvin, candela, and mole as standard measurements. |
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Thermistor |
A metal oxide bead whose resistance changes according to its temperature. |
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Thermodynamics |
The science of interconversion of heat and work. |
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Thermometer |
An instrument for measuring temperature. Usually consists of a sealed glass tube that is marked in degrees Celsius or Fahrenheit and contains a liquid such as mercury or alcohol. The liquid rises or falls as it expands or contracts according to changes in temperature. |
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Van der Waals forces |
Physical intermolecular forces that cause molecules to be attracted to each other. |
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Vaporization |
The process whereby matter in its liquid form is changed into its vapor or gaseous form. |
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Vapor pressure |
The force exerted by vapors on a gas or mixture of gases. |
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Vapors |
A transition state between liquid and a gas during which, through application of pressure/temperature changes, the transition may be reserved. |
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Volt (V) |
The unit of electrical potential. In an electric circuit, a volt is the force required to send 1 A of current through 1 ohm of resistance, or the difference in potential between two points on a conductor carrying a charge of 1 A when there is a dissipation of 1 W between them. |
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Voltmeter |
An instrument, such as a galvanometer that measures (in volts) the differences in potential between different points of an electric circuit. |
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Watts |
A unit of power, equivalent to work done at the rate of 1J/s. |
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Weight density |
Weight divided by its volume or dw=Mass/Volume. |
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Wheatstone bridge |
A particular arrangement of multiple resistors in an electrical circuit. |
