ENERGY REVIEW

• The Law of Conservation of EnergyEnergy is never created or destroyed it just

changes form

EnergyThe ability to cause change.

Types of EnergyChemical Energy- the energy stored in chemical bonds.

Nuclear Energy- the energy in the nucleus of every atom.

Types of Energy

Thermal Energy- the energy of an object that increases as temperature increases.

Radiant Energy- the energy carried by light.

Convection- the transfer of thermal energy through the movement of molecules from one part of a material to another.

• Cold Sinks

• Creates a Circular Current

• Heat Rises

Types of Energy

Electrical Energy- the energy carried by electrical current that comes out of batteries or electrical outlets.

Kinetic Energy- the energy an object has because of its motion

Converting Energy

Generator- a device that transforms kinetic energy into electrical energy.

Motor- a device that transforms electrical energy into kinetic energy.

Types of Energy• Potential Energy- energy that is stored in an

object because of its position

Electric Force- The attraction or repulsion between charged objects

Positive Charge Negative Charge

OPPOSITE CHARGES ATTRACT – AND + ATTRACT.

LIKE CHARGES REPEL – AND – REPEL,

+ AND + REPEL.

Electrical Forces

Electric field- the field or space in which charges exert a force on each other.

Electric discharge- the quick movement of electric charge from one place to another.

Types of Circuits

Series Circuit- a circuit that has only one

path for the electric current to follow.

Parallel circuit- a circuit that has more than

one path for the electric current to follow.

Controlling the Circuit

Voltage- the measure of how much electrical potential energy

each electron can gain.

Resistance- the measure of how difficult it

is for electrons to flow through a material.

• The unit of resistance is called

an ohm Ω

OHM’S LAW

The relationship among voltage, current, and resistance; when the voltage in a circuit increases the current increases.

ELECTRIC POWER

Power (in Watts) =Current (in amperes) x Voltage (in volts)P= I x V

POWERin watts

CURRENTin amperes

VOLTAGEin volts

Electromagnet- a wire with current flowing through it that is wrapped around an iron core.

How do they work?

Electrical SafetyAn Electric shock is when electric current flows through your body. Since nerves are electric signals shocks can disrupt your nervous system. A transformer changes the

electric voltage so the household appliances are not overloaded.

How magnets work.

Magnetic field-a space around a magnet where the magnetic force is active.

Magnetic Domain-a group of atoms with their magnetic fields pointing in the same direction.

Magnetosphere- the space affected by the Earth’s magnetic field.

The Sun and the Earth’s magnetosphere.

Charged particles

Aurora-the light given off from the sun’s charged particles crashing into atoms in the

Earth’s atmosphere.

Generating Energy

• Turbine- a set of steam powered fan blades that spins a generator at a power plant.

• Photovoltaic- a device that transforms radiant energy directly into electrical energy.

Renewable and Nonrenewable Resources

Gasoline is a nonrenewable resource.

Wood is a renewable resource.

Inexhaustible Resource- an energy source that cannot be used up by humans.

The Sun is an Inexhaustible Resource because we cannot use up that energy.

Alternative Resources- new renewable or inexhaustible resources.

Wind to generate energy.

The sun to power and heat houses

Electrical Energy to Power Transportation

How Does Energy Move?

• Waves-regular disturbances that carry energy without carrying matter.

Types of Waves

Mechanical Waves Electromagnetic Waves• Waves that use matter to

move energy.• Waves that can travel

through space where there is no matter.

Shapes of Waves

Transverse Waves-

Compressional /(Longitudinal) Waves-

• a type of mechanical wave in which the energy of the wave makes the wave move up and down or back and forth at right angles to the direction the wave travels

• A type of wave in which the matter in the medium moves forward and backward along the same direction that the wave travels.

Parts of a Transverse Wave

Crest-the top (peak) of a wave.

Trough-the bottom (dip)of a wave.

Frequency and Wavelength

The frequency is the number of waves that pass a point in space during any time interval, usually one second.

Waves with a longer wavelength will not pass a point as quickly as a wave with a shorter wavelength.

Descriptors of a Transverse Wave

• Amplitude- one half the distance between the crest and the trough.

• Wavelength- the distance from the top of one crest to the top of the next crest or from the bottom of one trough to the bottom of the next trough.

• Frequency- the number of wavelengths that pass a given point in one second

Parts of a Compressional/Longitudinal Wave

• Compression- the parts of a compressional/ longitudinal wave where the matter is closer together.

• Rarefaction- the parts of a compressional/ longitudinal wave where the matter is farther apart.

Descriptors of a Compressional/Longitudinal Wave

• Wavelength- the distance between the center of one compression and the center of the next compression or from the center of one rarefaction and the center of the next rarefaction.

• Amplitude- How close together the particles of a medium are.

• Frequency- the number of wavelengths that pass a given point in one second.

PROPERTIES OF WAVES

#1 Reflection

Occurs when a wave hits an object or surface and bounces off.

#2 Refraction

The bending of a wave as it moves from one medium to another.

Properties of Waves

The bending of waves around a barrier

• #3 Diffraction

Properties of Waves

#4