Science Lecture Review: Variables and Flight Physics

Vocabulary flashcards covering experimental design, scientific variables, Bernoulli's Principle, and the forces of flight.

Independent variable (IV)

The variable you are testing and deciding to change in an experiment, sometimes referred to as the 'I' variable.

Dependent variable (DV)

The variable that you measure in an experiment, which changes based on the independent variable.

Controlled variable (Constant)

A variable that is kept constantly the same so that only one independent variable is tested at a time.

Experimental group

The group in an experiment that receives the variable change being tested.

Control group

The group set up exactly like the experimental group except for the one variable being tested, used as a comparison.

Qualitative data

Data that is based on opinion.

Quantitative data

Data that is based on exact measurements and precise numbers.

Hypothesis

A predicted outcome of an experiment based on prior knowledge.

Bernoulli's Principle

States that the total mechanical energy of a moving fluid remains constant, implying that as a fluid moves faster its pressure gets lower, and as it moves slower its pressure gets higher.

Thrust

The forward push generated by the engines that makes an airplane move through the air.

Drag

The air resistance force that can slow an airplane down as it moves through the air.

Lift

The upward force that pushes a plane off the ground, created primarily by the wings.

Weight

The force of gravity pulling downwards on an airplane.

Newton's 3rd Law of Motion

States that for every action there is an equal but opposite reaction, meaning forces always act in pairs.

Action force (in airplane flight)

The downward force exerted on the air when an airplane's wings cut through the air.

Reaction force (in airplane flight)

The equal and opposite upward force of the air pushing back up on the airplane's wings.

Runway Takeoff Speed

Planes must travel over $150\,mph$ on the runway before taking off.

Balanced Forces on a Plane

When all forces acting on a moving plane are balanced ($\text{Net Force} = 0$), the plane maintains the same speed and same altitude.

Cruising Altitude Advantages ($30,000\,ft$)

Commercial airplanes cruise at $30,000\,ft$ because there is less air resulting in less drag (saving fuel), a smoother ride with less turbulence, and it is above weather systems.