Transfer of EnergyWaves and Circuits

• Energy: the ability to do work

• Wave: a disturbance that transfers energy from place to place

Types of Waves

Transverse Wave a wave that moves the medium at right angles (perpendicular) to the direction in which the wave is traveling

Transverse Waves• Crest: the highest part of a transverse wave

• Trough: the lowest part of a transverse wave

Motion in a Transverse Wave

What are the crest, trough, and rest position?

Types of WavesLongitudinal Wave a wave that moves the medium in the same direction (parallel) to the direction in which the wave is traveling

Longitudinal Waves• Compression: the part of a longitudinal wave

where the medium is pushed together• Rarefaction: the part of a longitudinal wave

where the medium is spread apart

Motion in a Longitudinal Wave

Which are the areas of compression and rarefaction in the diagram?

All waves (transverse and longitudinal) have the same properties:

Properties of WavesWavelength the distance between two corresponding parts of a wave (such as the distance from crest to crest or trough to trough)

Properties of WavesAmplitudethe maximum distance that the particles of the medium carrying the wave move away from their rest positions. The greater the amplitude, the greater the energy in a wave.

Properties of Waves

Wave Speedhow far the wave travels in a given length of time

Examples: •A tsunami wave travels through the ocean at approximately 600 mph.•Sound waves travel through the air at 768 mph.

Properties of Waves

Frequency

the number of waves that pass a certain point in a given amount of time; measured in Hertz (Hz) – 1 Hz is one wave per second

What are the properties of a wave?What are the parts of the wave?

Properties of Waves

All waves have amplitude, wavelength, frequency, and speed.

Wavelength

Wavelength

TRANSVERSE WAVE

Crest

Rest position Trough

Direction of wave

LONGITUDINAL WAVE

Compression

Amplitude

Rarefaction

Wavelength

Electric Circuits

• Electric Current – the continuous flow of electrons through a material

• Conductor – a material through which electrical charge can easily flow (metals such as silver, gold, copper, aluminum, and iron)

• Insulator – a material through which electrical charge cannot easily flow (rubber, glass, plastic, and wood)

ELECTRIC CIRCUITSa complete, unbroken path through which an electric current can flow

A symbol in a circuit diagram represents a part of the circuit.

Circuit DiagramsScientists use circuit diagrams to represent a circuit.

Battery

Wire

Device such as a light bulb

Switch

Component Circuit Symbol Function of Component

Wire To pass current very easily from one part of a circuit to another

BatterySupplies electrical energy. The larger terminal (on the left) is positive (+), and the smaller terminal (on the right) is negative (-).

Lamp (lighting)Symbol is used for a lamp that provides illumination, for example a car headlamp or light bulb.

Switch (On)Allows current to flow only when it is in the closed (on) position.

Switch (Off)Will not allow current to flow when it is in the open (off) position.

SERIES CIRCUITAll parts of the circuit are connected one after another along one path; in a series circuit there is only one path for the current to take

The number of bulbs in a series circuit affects each bulb’s brightness.

The different parts of the circuit are on separate branches; in a parallel circuit, there are several paths for the current to take

PARALLEL CIRCUIT

How Does an Electrical Circuit Work?Use the key to fill in the blank label boxes.

DIAGRAM PRACTICE

MORE PRACTICE