P-S

Pitch

The property of a sound and especially a musical tone that is determined by the frequency of the waves producing it highness or lowness of sound.

Precipitation

A deposit on the earth of hail, mist, rain, sleet or snow; also the quantity of water deposited.

Process

Human activities used to create, invent, design, transform, produce, control, maintain and use products or systems. A systematic sequence of actions that combines resources to produce an output.

Producer

Any of various organisms (such as a green plant) that produce their own organic compounds from simple precursors (such as carbon dioxide and inorganic nitrogen) and many of which are food sources for other organisms..

Prototype

A full-scale working model used to test a design concept by making actual observations and necessary adjustments.

Reflection

The return of light or sound waves from a surface.

Refraction

Deflection from a straight path undergone by a light ray or energy wave in passing obliquely from one medium (as air) into another (as glass) in which its velocity is different.

Resource

In a technological system, the basic technological resources are energy, capital, information, machines and tools, materials, people and time.

Revolve

To move in a curved path around a center or axis.

Rotate

To turn about and axis or a center.

Sedimentary Rocks

Rocks formed from material, including debris of organic origin, deposited as sediment by water, wind or ice and then consolidated by pressure.

Sketch

A rough drawing that represents the main features of an object or scene and often used as a preliminary study.

Solar System

A star (as the Sun) together with a group of celestial bodies that are held by its attraction and that revolve around it.

Solid

A substance that does not flow perceptibly under moderate stress, has a definite capacity for resisting forces (as compression and tension) that tend to deform it, and under ordinary conditions, retains a definite size and shape.

Synthetic Material

Material that is not found in nature, such as Styrofoam, concrete or plastics.

System

A group of interacting, interrelated or independent elements or parts that function together as a whole to accomplish a goal.