Properties and Structure of Solids

Vocabulary flashcards covering the physical properties, atomic structures, and mathematical principles of solids as presented in the lecture.

Solid

A material where molecules or atoms are very tightly bound together, giving the object a rigid volume and shape that does not change to fit a container.

Crystalline solid

A solid in which atoms are arranged in an orderly, repeating manner, such as diamonds, quartz, and snowflakes.

Unit cell

The regular, repeating atomic pattern in a crystalline solid that allows for the determination of the location of all other atoms.

Bools

Large silicon crystals grown in laboratories that are eventually sliced into wafers for computer chip manufacturing.

Amorphous solids

Solids with atomic arrangements that are disordered or lack an orderly arrangement, including materials like plastics, wax, and glass.

Polycrystalline materials

A class of material composed of many individual crystals, typically including most metals and ceramics.

Density ($D$)

A property defining how compact the matter in an object is, calculated using the equation $\text{mass} / \text{volume}$, with standard units of $kg/m^3$ or $g/cm^3$.

Osmium

The densest naturally occurring element, which has a density of $22.6\,g/cm^3$.

Liquid displacement method

A method to measure the volume of irregularly shaped objects by fully submerging them in water; every milliliter of water rise equals a volume of $1\,cm^3$.

Elasticity

The property of an object to return to its original shape after being deformed by a force.

Yield strength

The point at which a certain amount of applied force prevents an object from returning to its original configuration.

Ultimate strength

The maximum amount of force an object can withstand before it breaks.

Hooke's law

The mathematical definition for springs stated as $F = k \times \Delta X$, where $F$ is the force applied and $\Delta X$ is the deflection distance.

Spring constant ($k$)

A measure of a spring's stiffness, expressed in units of $N/m$; a larger constant indicates more force is needed for stretching.

Springs in series

Springs joined together end-to-end; the effective spring constant is smaller than individual constants because the combination is less stiff.

Springs in parallel

Springs joined together side-by-side; the effective spring constant is larger because the combination is stiffer and stretches less.

Tension

A force that exists when a solid object is pulled or stretched apart.

Compression

A force that exists when a solid object is pushed or squeezed together.

Neutral layer

The region in a deflected solid, such as the middle of a meter stick or beam, where no forces of tension or compression are acting.

I-beam

A structural beam with a carved-out center where no forces act, reducing weight and cost while maintaining material at the top and bottom for tension and compression.

Scaling

The study of how properties like surface area, volume, and weight change as an object's size increases or decreases.

Surface area to volume ratio

A ratio indicating how strong something is compared to its weight; for a cube with edge length $X$, the ratio is calculated as $6/X$.

Lycopodium powder

A dry, flammable powder used to demonstrate that chemical reactions are more vigorous when reactants have more exposed surface area.