Reflection/ wave shape/Incident and reflected waves

By: Marc Palmer and Joe Smith

Reflection

• The Law of Reflection• Light is known to behave in a very predictable

manner. If a ray of light could be observed approaching and reflecting off of a flat mirror, then the behavior of the light as it reflects would follow a predictable law known as the law of reflection.

Reflection Continued…• In the diagram, the ray of light approaching the mirror is

known as the incident ray (labeled I in the diagram). The ray of light which leaves the mirror is known as the reflected ray (labeled R in the diagram). At the point of incidence where the ray strikes the mirror, a line can be drawn perpendicular to the surface of the mirror.

Reflection continued…Reflection involves a change in direction of the light ray. The angle of incidence is the angle between this normal line and the incident ray; the angle of reflection is the angle between this normal line and the reflected ray.

Reflection Continued…According to the law of reflection, the angle of incidence equals the angle of reflection. These concepts are illustrated in the animation below.

Reflection Continued…

Reflection continued…Reflection off of smooth surfaces such as mirrors or a calm body of water leads to a type of reflection known as specular reflection. Reflection off of rough surfaces such as clothing, paper, and the asphalt roadway leads to a type of reflection known as diffuse reflection. Whether the surface is microscopically rough or smooth has a tremendous impact upon the subsequent reflection of a beam of light. The diagram below depicts two beams of light incident upon a rough and a smooth surface.

WavesA wave can be described as a disturbance that travels through a medium from one location to another location. Consider a slinky wave as an example of a wave. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. The coils of the slinky naturally assume this position, spaced equally far apart.

Waves continued…

A Wave Transports Energy and Not Matter

When a wave is present in a medium (that is, when there is a disturbance

moving through a medium), the individual particles of the medium are only

temporarily displaced from their rest position. There is always a force acting

upon the particles which restores them to their original position.

Waves Continued…Waves are said to be an energy transport phenomenon. As a disturbance moves through a medium from one particle to its adjacent particle, energy is being transported from one end of the medium to the other.

Waves Continued…

Waves are seen to move through an ocean or lake; yet the water always returns

to its rest position. Energy is transported through the medium, yet the water

molecules are not transported. Proof of this is the fact that there is still water in

the middle of the ocean. The water has not moved from the middle of the ocean

to the shore.

Waves Continued…In conclusion a wave can be described as a disturbance which travels through a medium, transporting energy from one location its source to another location without transporting matter. Each individual particle of the medium is temporarily displaced and then returns to its original equilibrium positioned.

Test•The behavior of the light as it reflects would follow a predictable law known as______________

•Reflection involves a change in direction of the _____________________

•According to the law of reflection , the angle of incidence equals_____________________

•Reflection off of smooth surfaces as mirrors or a calm body of water leads to a type of reflection known

as_______________________

•A wave transports___________ not matter.

Answers

1. Law of reflection2. Light ray3. The angle of reflection4. Specular reflection 5. Wave6. Energy

Waves/Reflection/Refraction

By Jen Cantor & Meghan LeporePer.5

Waves in the ocean

• Our world would be a different place without waves.

• Waves and winds work side by side in the environment to produce natural storms, move nutrients in the ocean, transport warm currents and cold currents, they also help erode rocks and sand which is the natural cycle of earth.

a wave's energy is proportional to the square of its height

3m high wave has 3x3=9 times more energy than a 1m high wave

Reflection of light waves

Law of Reflection: the waves will always reflect in such a way that the angle at which they approach the barrier equals the angle at which they reflect off the barrier.

Reflection• Reflection involves a change in direction of

waves when they bounce off a barrier• Reflection of waves off parabolic barriers

results in the waves coming together at one point

Refraction

• Refraction is the change in direction of waves when they travel from one medium to another

• Refraction is followed by a wavelength and speed change

Refraction

• Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.

Sound waves

• Sound is a mechanical vibration that travels through the air as a wavelength.

• The tighter the waves the higher the frequency

characteristics

• Sound waves have generic characteristics : frequency, wavelength, period, amplitude, intensity, speed, and direction.

• Speed+ Direction = velocity vector• Wavelength + Direction = wave vector

longitudinal waves • Longitudinal (also known as compression

waves):transmitted through gases, plasma, and liquids, solids.

• Longitudinal :are waves that alternate pressure from the equilibrium pressure.

Transverse waves

• Transverse waves: can be transmitted through solids as well

• Transverse: alternate sheer stress from a right angle to direction of propagation

Multiple Choice

1)Waves move nutrients around in?a.your body c. oceans b.fish d. on land

2)Reflection involves a change in?a. speed c. height b. direction d. distance

3)What is refraction followed by?a. air c. lightb.Ms. I d. wavelength and speed change

• 4)The tighter the sound wave the higher the?a. frequency c. speedb.distance d. Height

• 5)After reflection waves come together at?a. at a circle c. at one pointb.they don’t d. the shape of a triangle

Short Answer6. Name 3 characteristics of sound waves…

7. ______+_______ = velocity vector

8. Wavelength + Direction =__________

9. Longitudinal waves are also known as _____

10. Transverse waves can be _______ through solids

MC answers/Short Answer• 1. c 6. frequency, wavelength, speed• 2. b 7. Speed+ Direction• 3. d 8. =wave vector• 4. a 9. compression waves• 5. c 10. transmitted

Bibliography

• www.seafriends.org• www.wikipedia.com • www.schoolforchampions.com• www.google.com /images