Science Energy

Energy

The ability to do work or cause change.

Joule (J)

The unit of energy.

Law of Conservation of Energy

Energy cannot be created or destroyed; it can only be transferred or transformed.

Chemical Energy

Potential energy stored in the chemical bonds of atoms and molecules.

Examples of Chemical Energy

Batteries, food (digestion), photosynthesis, fuel.

Electrical Energy

Energy caused by the movement of electrons through a conductor.

Examples of Electrical Energy

Lightning, vacuums, toasters, phones, power lines.

Kinetic Energy

Energy an object has due to its motion.

Examples of Kinetic Energy

Walking, throwing a ball, a moving car, running water.

Mechanical Energy

The total energy of an object's motion and position.

Mechanical Energy Formula

Mechanical Energy = Potential Energy + Kinetic Energy.

Examples of Mechanical Energy

A moving car, a swinging pendulum, a roller coaster.

Nuclear Energy

Energy stored in the nucleus of an atom/ Fission and Fusion

Examples of Nuclear Energy

Nuclear power plants, the Sun, nuclear reactions.

Potential Energy

Stored energy based on an object's position, shape, or state.

Examples of Potential Energy

A car at the top of a hill, a stretched bow, a water bottle on a desk.

Types of Potential Energy

Gravitational, Chemical, Elastic.

Gravitational Potential Energy

Energy stored due to height above the ground.

Chemical Potential Energy

Energy stored in chemical bonds.

Elastic Potential Energy

Energy stored when an object is stretched or compressed.

Radiant (Light) Energy

Energy that travels in electromagnetic waves.

Examples of Radiant Energy

Sunlight, light bulbs, lasers, fire.

Thermal (Heat) Energy

Energy related to the temperature of an object.

Examples of Thermal Energy

Fire, hot stove, warm water.

Conduction

Transfer of thermal energy through direct contact.

Examples of Conduction

Touching a hot pan and your hand gets hot.

Convection

Transfer of thermal energy through the movement of liquids or gases.

Examples of Convection

Boiling water, warm air rising, ocean currents.

Radiation

Transfer of energy through electromagnetic waves.

Examples of Radiation

Sunlight warming Earth, feeling heat from a fire.

What does thermal energy depend on?

How fast particles move.

What happens to particles in hot objects?

Particles move faster and are more spread out.

What is the density of hot air or liquid?

Hot air or liquid is less dense.

What occurs in cold objects regarding particle motion?

Particles move slower and are closer together.

What is the density of cold air or liquid?

Cold air or liquid is more dense.

What causes hot fluids to rise?

Hot fluids are less dense than cold fluids.

What causes cold fluids to sink?

Cold fluids are more dense than hot fluids.

How does convection create wind during the day?

Land heats up faster than water, causing warm air to rise and cooler air to move in.

What is a convection current?

A circular movement of air caused by differences in temperature and density.

What happens to air above the land during the day?

It gets warm, becomes less dense, and rises.

What moves toward the land to replace rising warm air?

Cooler air from above the water.

What is felt as wind during the day?

The surface movement of cool air from water to land.

What is speed?

How fast an object moves; distance ÷ time (m/s)

What is velocity?

Speed with direction (m/s)

What is acceleration?

Rate at which velocity changes (m/s²)

What is gravity?

Force of attraction between ALL objects

What is the acceleration due to gravity on Earth?

9.8 m/s² downward

What is a force?

A push or a pull

What unit is force measured in?

Newton (N)

What is a Newton?

Force needed to accelerate 1 kg by 1 m/s²

What is a vector?

An arrow showing force magnitude and direction

What does magnitude mean in a vector?

The size or strength of the force

What is vector analysis?

Adding forces to find the total force

What is net force?

The overall force acting on an object

What are balanced forces?

Equal forces in opposite directions; net force = 0

What happens when forces are balanced?

Object stays at rest or moves at constant velocity

What are unbalanced forces?

Forces are not equal; net force ≠ 0

What happens when forces are unbalanced?

Object accelerates

What is Newton's First Law?

Objects stay at rest or in motion unless acted on by an unbalanced force

What is Newton's Second Law?

Force equals mass times acceleration (F = ma)

What is Newton's Third Law?

Every action has an equal and opposite reaction

What is weight?

The force of gravity acting on an object (N)

What is mass?

The amount of matter in an object (g or kg)

How are weight and mass different?

Mass stays the same; weight changes with gravity

How does mass affect gravity?

More mass = stronger gravitational force

How does distance affect gravity?

More distance = weaker gravitational force

What is free fall?

Falling with only gravity acting (no air resistance)

What is terminal velocity?

Maximum speed reached when air resistance equals gravity

What is projectile motion?

The curved path an object follows when thrown

What is energy?

The ability to do work (J)

What unit is energy measured in?

Joules (J)

What is kinetic energy?

Energy of motion (J)

What is potential energy?

Stored energy due to position or height (J)