What is a wave? A disturbance that travels through a medium from one location to another location A medium is a substance or material which carries the wave

Rhythmic disturbances that carry energy without carrying matter What are Waves? Rhythmic disturbances that carry energy without carrying matter

Longitudinal (Compression Waves) Are composed of Compressions, where the parts of the medium (coils of the Slinky) are closer together than normal In this demonstration, you created (generated) compressional longitudinal waves The waves traveled through a media (the slinky)

Vibrates perpendicular (at right angles) to the wave travel Transverse Vibrates perpendicular (at right angles) to the wave travel Electromagnetic waves Animation courtesy of Dr. Dan Russell, Kettering University

A combination of longitudinal & transverse Water Waves A combination of longitudinal & transverse Animation courtesy of Dr. Dan Russell, Kettering University

Types of Waves Mechanical Waves – need matter (or medium) to transfer energy A medium is the substance through which a wave can travel. Ex. Air; water; particles; strings; solids; liquids; gases Electromagnetic Waves – DO NOT NEED matter (or medium) to transfer energy They do not need a medium, but they can go through matter (medium), such as air, water, and glass

Electromagnetic Waves Wave which is capable of transmitting its energy through a vacuum (i.e., empty space) Produced by the vibration of electrons within atoms on the Sun's surface Travel through space until they reach Earth These waves subsequently travel through the vacuum of outer space, subsequently reaching Earth

Mechanical Waves Are not capable of transmitting its energy through a vacuum (space) Require a medium in order to transport their energy from one location to another

Mechanical Waves Waves traveling through a solid medium can be either transverse waves or longitudinal waves Waves traveling through a fluid (such as a liquid or a gas) are always longitudinal waves

Waves that need matter (medium) to transfer energy: Mechanical Waves Waves that need matter (medium) to transfer energy: Examples: Sound waves, ocean waves, ripples in water, earthquakes, wave of people at a sporting event

Some examples of Mechanical Waves

Use the next four slides and your Wave Diagram sheet to label and define the parts of a Transverse wave.

Parts of a Transverse Wave The crest is the highest point on a wave.

Parts of a Transverse Wave The trough is the valley between two waves, is the lowest point.

Parts of a Transverse Wave The wavelength is the horizontal distance, either between the crests or troughs of two consecutive waves.

Parts of a Transverse Wave The amplitude is the peak (greatest) value (either positive or negative) of a wave. The distance from the undisturbed level to the trough or crest.

An ocean wave is an example of a mechanical transverse wave

Compressional Wave (longitudinal) A mechanical wave in which matter in the medium moves forward and backward along the same direction that the wave travels. Ex. Sound waves A slinky is a good illustration of how a compressional wave moves

Use the next three slides and your Wave Diagram sheet to label and define the parts of a Compressional wave.

Parts of a Compressional Wave (Longitudinal) The compression is the part of the compressional wave where the particles are crowded together.

Parts of a Compressional Wave (Longitudinal) The rarefaction is the part of the compressional wave where the particles are spread apart.

Parts of a Compressional Wave (Longitudinal) The wavelength is the distance from compression to compression or rarefaction to rarefaction in a compressional wave.

Electromagnetic Waves Waves that DO NOT NEED matter (medium) to transfer energy Examples: radiation, TV & radio waves, X-rays, microwaves, lasers, energy from the sun, visible light Electromagnetic waves are considered transverse waves because they have similar characteristics; therefore, they have the same parts.

Electromagnetic Spectrum The electromagnetic spectrum illustrates the range of wavelengths and frequencies of electromagnetic waves.

Speed Frequency (f)- the number of crests of a wave that move past a given point in a given unit of time. The most common unit of frequency is the hertz (Hz), corresponding to one crest per second. 

Speed Period (T)- Amount of time for a wave to complete one cycle. Measured in seconds (s)

Calculating the Speed of a Wave

Calculate the Wave Speed Medium Wavelength Frequency Speed Zinc,1-in. dia. coils 1.75 m 2.0 Hz ______ 0.90 m 3.9 Hz Copper,1-in. dia. coils 1.19 m 2.1 Hz 0.60 m 4.2 Hz Zinc,3-in. dia. coils 0.95 m 2.2 Hz 1.82 m 1.2 Hz 3.5 m/s 1. 2. 3.5 m/s 3. 2.5 m/s 4. 2.5 m/s 5. 2.1 m/s 6. 2.2 m/s

Reflection Reflection- When a wave travelling on one medium strikes the surface of a different medium and changes direction so that it returns back into the medium in which it was originally travelling in

Reflection Incident Ray- is a ray of light that strikes a surface Reflected Ray- the ray that represents the light reflected by the surface. The angle between the surface normal and the reflected ray is known as the angle of reflection.

angle of incidence -The angle at which incoming light rays approaches a surface. it is located between the light ray and the normal angle of reflection- The angle at which light rays are reflected, or bounced off, of a surface

Reflection Law of Reflection- The angle of incidence equals the angle of reflection

Reflection with Mirrors Reflection on plane mirrors- Image in plane mirrors is virtual, upright, laterally inverted at the same distance from the mirror as the object's distance, and the same size as the object

Reflection with Mirrors

Refraction Refraction- The change of speed of a wave when the density it travels through, changes. The direction of the wave changes because of the change in speed Density- The mass of an object Angle of refraction- The angle between the refracted ray and the normal

Critical Angle- A specific value for the angle of incidence that yields an angle of refraction of 90 degrees. Total internal reflection- the complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is greater than the critical angle Fiber optics- Thin, flexible and transparent fibers that are made of pure glass. They efficiently transmit light pulses over long distances. Mirages- An optical phenomenon, especially in the desert or at sea, by which the image of some object appears displaced above, below, or to one side of its true position as a result of spatial variations of the index of refraction of air

Critical Angle

Total Internal Reflection

Mirages