| Class Vocabulary | |
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atom
| The smallest distinguishable unit of a material that maintains the same characteristics. |
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conductor
| A material that is very effective at conducting electricity. Metals are generally excellent conductors. |
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coolant
| A substance that is used to prevent a workpiece from reaching excessively high temperatures during machining. |
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corrosion
| The deterioration of a metal or ceramic. |
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covalent bond
| A type of atomic bond that occurs when two atoms share electrons. |
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crevice corrosion
| The corrosion of a metal at the joints of a workpiece or component. |
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degradation
| The deterioration of a plastic or polymer. |
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density
| The relative compactness of a material. Density is the mass of a material per unit volume. |
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electrical conductivity
| The ability of a material to convey electricity. |
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electron
| The smallest part of the atom that revolves around the nucleus. Electrons have a negative charge, and they are the basic charge of electricity. |
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electron cloud
| A sea of electrons that lets electrons freely move around within a metallic bond. |
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freezing point
| The temperature necessary to change a liquid to a solid. |
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gravity
| The force exerted by the Earth on other objects at or near its surface. |
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heat of fusion
| The additional heat that is initially necessary to cause a material to begin to melt. |
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insulator
| A material that is highly resistant to the flow of electricity. Ceramics and polymers are excellent insulators. |
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ionic bond
| A type of atomic bond that occurs when one atom borrows one or more electrons from another atom. |
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liquidus
| The temperature at which an alloy completely finishes melting. |
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mass
| The amount of matter that is contained within an object. |
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mechanical force
| The application of a force that bends, dents, scratches, compresses, or breaks a material. |
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melting point
| The temperature necessary to change a solid to a liquid. |
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metal alloy
| A solid combination or mixture of two or more metals, in which the atoms of one metal occupy little spaces between the atoms of the other. |
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metallic bond
| A type of atomic bond that occurs when atoms share electrons that float about in a general electron cloud. Metals are held together by metallic bonds. |
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molecule
| The smallest unit into which a material can be divided without changing its properties. A molecule consists of a group of atoms held together by strong primary bonds. |
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passivation
| Helpful corrosion that protects a material from other harmful effects. |
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physical properties
| The way that a material reacts to forces other than mechanical forces. Melting, freezing, thermal conductivity, and electrical conductivity are all physical properties. |
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pitting
| The corrosion of a metal that takes place in specific locations on a workpiece or component. |
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resistor
| A material that resists the flow of electricity. |
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solidus
| The temperature at which a solid alloy begins to melt. |
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specific heat
| The amount of heat that is required to raise the temperature of a specific amount of material by one degree. |
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strength-to-weight ratio
| The relationship between a material's strength and its weight. Materials that are light but also very strong have a high strength-to-weight ratio. |
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thermal conductivity
| The ability of a material to conduct heat. |
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thermal expansion
| The tendency of a material to increase in size as it increases in temperature. |
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thermal stresses
| A decrease in the quality of a material that occurs due to excessive changes in temperature. |
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weight
| The degree of heaviness of an object that results from the gravitational pull of Earth. |