High School‎ > ‎Science‎ > ‎Engineering‎ > ‎

Important Terms

Fluids - are substances that flow easily, such as liquids and gases

Pressure -
is a force per unit area P = F/A  
    It is often used to describe 
            * force exerted by a contained liquid on the walls of its container
            * force exerted by a contained liquid on the surface of an object submerged in it

Buoyant Force -
the upward push on the object, equals the weight of the volume of water displaced by an object

Surface -
The outer or the topmost boundary of an object

Sinks -
when the volume of an object weighs more than the volume of water it displaces - it sinks

Expands -
to increase the extent, number, volume, or scope of

Neutral Buoyancy-
is a condition in which a physical body's mass equals the mass it displaces in a surrounding medium. This offsets the force of gravity that would otherwise cause the object to sink. An object that has neutral buoyancy will neither sink nor rise.

is how much three-dimensional space a solid, liquid, gas occupies, often quantified numerically.

To ascend or float in a fluid, as gases or vapors in air, cork in water, and the like. (c) To move upward under the influence of a projecting force; as, a bullet rises in the air.

Newton's 1st  Law of Motion - 
An object in uniform motion will continue in uniform motion unless acted on by an outside force.

Newton's 3rd Law of Motion -
Every action has an equal and opposite reaction!! The (mass * acceleration) of the gas ejected from the rocket engine backward = the (mass * acceleration) of the rocket forward. "Acceleration" is the scientific term for speeding up.

Resistance -
is any force that opposes motion

Closed System Engine -
the working fluid remains within the system

Open System Engine - the working fluid moves across the system boundary

Convection -
is an energy transfer due to fluid motion

Renewable Energy -
source is an energy source that is naturally replenished in a short amount of time (wind, solar, wood are examples)

Elements -
substances that have only one kind of atom

are the smallest particle of a chemical element that retains its chemical process

Molecule - 
is the smallest particle of a material that still has all the chemical properties of that materials. Usually a molecule has two  more atoms

Chemical Reactions -
molecules break apart and atoms are rearranged into new molecules

Hydrostatic Pressure -
Hydrostatic pressure is the pressure exerted by a fluid at equilibrium due to the force of gravity.

- Heat flow/Energy Transfer via direct contact

- A material through which energy passes easily - most metals are good conductors of thermal and electrical energy

- process that occurs when an object is pressed together

- the energy transmitted in all directions from a source in the form of waves and rays

- Energy transfer due to fluid motion -ex in a house hot air displaces cold air  and then cold air displaces hot air

- the capability of a strained body to recover its size and shape after deformation

- Capable of being shaped or formed, as by hammering or pressure

- the ability of being shaped or form

Tensile Strength
- The resistance of a material to a force tending to tear it apart, measured as the maximum tension the material can withstand without tearing.

- Likely to break, snap, or crack, as when subjected to pressure

Tension - a force related to the stretching of an object (the opposite of compression)

Torsion - the twisting of an object due to an applied torque

Dead Load
- weights of material, equipment, or components that are relatively constant throughout the structure's life. Dead loads are not limited to walls, floors, roofs, ceilings, stairways, built-in partitions, finishes, cladding and other similarly incorporated architectural and structural items, and fixed services equipment, including the weight of cranes. All permanent loads are considered dead loads

Live Load
- sometimes referred to as probabilistic loads include all the forces that are variable within the object's normal operation cycle not including construction or environmental loads. Using the staircase example the live load would be considered to be –
  • Pressure of feet on the stair treads (variable depending on usage and size)
  • Wind load (if the staircase happens to be outside)
Live loads (roof) produced (1) during maintenance by workers, equipment and materials; and (2) during the life of the structure by movable objects such as planters and by people

- An applied force or system of forces that tends to produce a shearing strain. Also called shearing stress, shear stress.

- A force that produces tension on one side of an object and compression on the other side.