Homework Finish lab! Do Now: Draw a diagram of a pendulum and list what you could change about it. AIM: How do we determine which factors affect the period.

Homework Finish lab! Do Now: Draw a diagram of a pendulum and list what you could change about it. AIM: How do we determine which factors affect the period of a pendulum?

What are three things you can change about an pendulum? – What would be the period of a pendulum? How could you test if each of these factors affect the period of a pendulum? http://www.youtube.com/watch?v=r2gnD5NEplY Properties of a Pendulum

Lab Goal: which factors affect the period of a pendulum? Groups 1, 2: – Does mass affect the period of a pendulum? Groups 3, 4: – Does length affect the period of a pendulum? Groups 5, 6, 7: – Does release height affect the period f a pendulum?

Lab Write-up Goals (all 3) Background: – What is a pendulum? – What is period? Predictions: – Which of the factors will effect the period of a pendulum? Procedures: – Mass – Length – Initial height Data/Analysis: Conclusion:

Homework Do Now: Draw a wave and label any part of the wave you know. AIM: What is a wave and how do we describe them? Blue book pg 153-155 #1-47

Simple Harmonic Oscillators An object in simple harmonic motion experiences a net force which obeys Hooke’s Law The oscillator oscillates about an equilibrium position (or mean position) between two extreme positions of maximum displacement in a periodic manner – Periodic means regular (same every time) and repeating Mass on a spring pendulum

Parameters and parts of waves

Vocabulary Period (T): – The time for one oscillation – Measured in Seconds – Period = Time/number of oscillations Frequency (f) – The number of oscillations in one second – Measured in Hertz; Hz (1/s or s -1 ) – Frequency = Number of oscillations/time Mathematical Relationship between Period and Frequency – Period and frequency are inversely related

Examples 1.A mass on a spring completes 10 oscillations in 30 seconds. a.What is the period of oscillation? b.What is the frequency of oscillation? 2.A pendulum completes 5 swings in a minute a.What is the frequency of oscillation? b.What is the period of oscillation?

Waves are repetitive disturbances that transfer ENERGY without transferring MATTER – energy transferred without matter being transfered energy transferred without matter being transfered Mechanical Waves require a medium to travel through. Mediums include; water, air, anything solid SOUND is a mechanical wave "the wave" Electromagnetic Waves do not require a medium to travel through. They can travel through a vacuum (empty space) Empty space exists outside of Earth’s atmosphere LIGHT, Xrays, Radio Waves are all examples of electromagnetic waves electromagnetic waves Waves

ALL electromagnetic waves travel at the speed of light! – c is the symbol for the constant “speed of light” – c is always equal to 3x10 8 m/s when electromagnetic waves are traveling through a vacuum. This speed can be decreased by sending light through a different medium Nothing can ever travel faster than the speed of light. Visible light is the same type of wave as a radio wave, an Xray, or a microwave. Its just a different size! electromagnetic spectrum The Electromagnetic Spectrum

VERY small wavelengths VERY high frequencies VERY high wavelengths VERY low frequencies Visible Spectrum. Each color is within these FREQUENCY ranges. Remember, higher frequency, lower wavelength

The Electromagnetic Spectrum Nanometers Kilometers Megahertz meters Gigahertz

Two Classes of Waves Transverse Waves The particles vibrate in a direction that is perpendicular to the waves propagation (direction of travel) Longitudinal Waves The particles vibrate in a direction that is parallel to the waves propagation (aka compression waves)

Parts of a Wave Crest: the top-most part of a wave Trough: the bottom-most part of a wave Amplitude: the distance from the equilibrium line to the crest or to the trough (measure in meters) Wavelength (λ): the distance between two similar points on a wave (measured in meters)

Wave Pulse One single Vibration or disturbance - The amplitude of SOUND ONLY tells you about the energy in the wave Transverse Pulse Longitudinal Pulse One Crest Or One Trough One rarefaction Or One compression

Phase The relative position between… – Two different points on the same wave Phase is measured in degrees and follows the conventions of a sine curve. Reference Point 0 o 90 o One-quarter wavelength 180 o Half wavelength 270 o three-quarter wavelength 360 o One full wavelength

Phase The relative position between… – Two similar points on different waves Pick the same point on each wave and look at the difference between their relative positions 90 o out of phase, 1/4 wave apart180 o out of phase, 1/2 wave apart 270 o out of phase, 3/4 wave apart 360 o out of phase, AKA IN PHASE 1 full wavelength apart

Homework AIM: What affects the speed of a wave? How do we calculate a wave’s speed Finish 1-47 in the blue book. Questions are posted on the website QUIZ ON THEM TOMORROW! Do NOW! Make a compare and contrast list of everything you know about sound waves and light waves

Sound Waves vs. Light Waves Sound Waves Mechanical Wave Longitudinal wave Amplitude tells you about volume Frequency tells you about pitch The speed of sound in air is about 330m/s Sound travels faster in most solids than it does in air Light Waves Electromagnetic wave Transverse wave Amplitude tells you about intensity/brightness Frequency tells you about type of wave/color The speed of light in air is 3x10 8 m/s Light slows down in solids

You are standing on a dock and observe 15 waves pass you in 1 minute. – What is the frequency of the waves? – What is the period of the wave? What is the difference between a mechanical and electromagnetic wave? What is the difference between a transverse and longitudinal wave? Recall…

standing wave A wave that appears to be “standing still” and not moving either left or right. - Particles seem to vibrate up and down In order to create a standing wave, you need - Two waves, moving in opposite directions, with the same amplitude and frequency Nodes: points that don’t moveAntinodes: points that move the most

Measuring Parameters of a Wave Goal: we are going to use a standing wave to measure and investigate the affect of the amplitude, frequency, period, and wavelength on the speed of a transverse wave. Prediction: Which of the four parameters do you think will affect the speed of the wave and why. Background: in a paragraph, please define all bolded words above. Diagram: Draw a diagram of a transverse wave and label all the parts of the wave. Materials – Slinky, stopwatch, meter stick

Procedure – Measure 4m length across the floor and a 0.5m and 1m amplitude. – Have one person hold one end of the slinky still while having the other person generate a half wavelength standing wave with a 0.5m amplitude – Have 10 classmates time 20 complete oscillations of the wave. – Calculate the period, frequency and wave length for this trail and enter the numbers into the data table. – Repeat for a 1m amplitude then for 1 wave, 1.5 waves, 2 waves, 2.5 waves and possibly 3 waves. – Using the data table, try to determine how you would calculate the speed of the wave. – Once the speed for each wave is calculated, determine which parameters affect the speed of the wave and which don’t.

Data Small AmplitudeLarge Amplitude wavelength (m) Time for 20 (s) Period (s) Frequency (Hz) Speed (m/s) wavelength (m) Time for 20 (s) Period (s) Frequency (Hz) Speed (m/s)

Analysis – Show a sample calculation for each of the following Period of the wave Frequency of the wave Speed of the wave. – What formula did you come up with to calculate this? (hint: use the units!) Percent difference between velocities. – Do they appear different? Conclusion – Restate goal – What is the formula for the speed of the wave? – What parameters affect the speed, which don’t? If the frequency was changed, did the speed or the wavelength change? – How could you change the speed of this wave? – Sources of error/one future experiment

Calculating the speed of a wave 1.A 5m long wave passes the end of a dock once every 10 seconds. a.What is the period of the wave? b.What is the speed of the wave? 2.A light wave has a frequency of 6MHz a.What is the frequency in Hertz? b.What is the speed of the wave? c.What is the wavelength of the light? d.What type of light wave is this?

Do Now WORKING ON YOUR OWN, complete the crossword. You can use your notes. You have 7 minutes from the beginning of the period. If you finish, take out the lab we worked on yesterday and finish writing the background and write a conclusion paragraph Conclusion – Restate goal – What is the formula for the speed of the wave? – What parameters affect the speed, which don’t? If the frequency was changed, did the speed or the wavelength change? – How could you change the speed of this wave? – Sources of error/one future experiment

Homework Castle Learning Assignment due Monday! Do Now: Describe what you heard and explain it in terms of reflection AIM: What is Reflection? http://www.youtube.com/watch?v=kVzTWDwQzrc&feature=related

Wave Behaviors

3 Options When a wave hits a boundary, it does a combination of 3 things – Reflection Bounces off the boundary – Absorption Gets absorbed and turned into heat – Transmission Goes through the boundary The transmission of the lights on the inside of the building The reflection of the lights coming off the car on the outside of the building

Law of Reflection How to draw the diagram The Law of Reflection states –A–Angle of incidence is equal to the angle of reflection i r Normal Line: A reference line always drawn perpendicular to the surface USE A PROTRACTOR!!!! Angle of incidence i : angle made between the incident ray and the normal line Incidence Ray: The light ray on the way INTO the surface Reflected Ray: The light ray on the way AWAY FROM the surface Angle of Reflection r : angle made between the reflected ray and the normal line

Reflection of Light The bouncing of a wave off of a surface. – Regular reflection Bouncing off of a Smooth surface – Mirrors, ponds – You can see an image of the object – Diffuse Reflection Bouncing off of a Rough surface – The road, leaves, furniture, cloths – You can see light, but no image

Reflection of sound The bouncing of a wave off of a surface. – Regular reflection Bouncing off of a Smooth surface ECHOs If the speed of sound in water is 1.5Km/s and the signal takes 0.8 seconds to come back to the boat, HOW DEEP IS THE WATER?

Echos A person in the grand canyon screams and hears the sound come back to her 1.2 seconds later. How far away is the other face of the canyon?

Reflection Ray Diagram Object Mirror Normal Line Incident Rays Incident Angle Reflected Ray Reflected Angle Eye sees two diverging rays and traces them back Image Appears where the virtual rays cross Object DistanceImage Distance Law of Reflection in a PLANE mirror: -O-Object distance (d o ) is equal to image distance (d i )

Reflection Lab Goals: 1.To draw a 2-ray diagram of a single pin image a.Use this diagram to compare the incident angles to the reflected angle -Use percent difference to determine if the object distance is the same as the image distance b.Use this diagram to compare image distance to object distance -Use percent difference to determine if the object distance is the same as the image distance

1. Draw a line down the middle of the page, perpendicular to the edge of the page

2. Prop the mirror up against the book with the BACK surface of the mirror on your mirror line. Make sure the cardboard is under the paper

3. Stick the pin in the middle of the page

4. Look in the mirror from the angle and locate the image of the pin in the mirror Image of the pin

5. Line up the edge of the ruler such that if extended into the mirror, it would run straight into the pin. Trace that line

6. Repeat step 5 from the other side

7. Extend the reflected rays back to the mirror 8. Draw a line connecting the object to the place on the mirror where the reflected rays hit

9. Trace the VIRTUAL rays back behind the mirror. The image appears where the rays meet

10. Use a protractor to construct the normal perpendicular to the mirror at the point where the rays hit the mirror. 11. Measure both incident and reflected rays and compare them using a percent difference

12. Label and measure the object distance and the image distance. Using percent difference, compare these two numbers

Goals Continued 2.To draw a 2-ray diagram of a single pin image a.Use this diagram to compare the incident angles to the reflected angle -Use percent difference to determine if the object distance is the same as the image distance b.Use this diagram to compare image size to object size -Measure the length of each side of the image and the object. -Use percent difference to determine if the object distance is the same as the image distance

When light rays from an object are incident upon an opaque, rough-textured surface, no reflected image of the object can be seen. This phenomenon occurs because of 1. regular reflection 2. diffuse reflection 3. reflected angles not being equal to incident angles 4. reflected angles not being equal to refracted angles A typical microwave oven produces radiation at a frequency of 1.0 × 10 10 hertz. What is the wavelength of this microwave radiation? 1. 3.0 × 10 -1 m 2. 3.0 × 10 -2 m 3. 3.0 × 10 10 m 4. 3.0 × 10 18 m At the instant shown, a cork at point P on the water's surface is moving toward A B C D

Electromagnetic radiation would be classified as 1. a torsional wave 2. a longitudinal wave 3. a transverse wave 4. an elliptical wave

Standing Waves Revisited Do Now: -What are the three conditions that need to be met to produce a standing wave? -An example of a standing sound wave Rubens flame tube HW MAKE A REVIEW SHEET

Sound as Music -What is the relationship between frequency and pitch? -Think of a trombone, how does the pitch of the sound change as the length of the slide increases? -Based on this, how is frequency related to wavelength? blue man group – What do you notice about the length of the tubes and the pitch of the waves? Does this confirm your statement above?

Reflection Continued Fixed end Reflection – 180 o phase change Free end Reflection – No phase change fixed and free end reflection Incident Crest Reflected Trough Incident Crest Reflected Crest

Resonance Resonance is… When a small amount of energy… Added at the right frequency… Produces a large amplitude… resonance tuning forks glass breaking 1 breaking glass 2 glass music

Questions on the videos Video 1 – What type of wave would be produced in the ping pong balls when hit with the paddle? – What characteristic of sound does the frequency tell you about? – When is one tuning fork able to resonate with another? When doesn’t it work? – How does your radio work? Video 2/3 – why is the sound of the glass considered resonance? – What happened to the frequency when he added water? – What would happen to the sound wave’s wavelength when the water was added? – What would happen to the glass if he changed the frequency of the sound generator? Video 4 – What do you notice about the pitches of the sound and the size of the glasses? – Can you come up with an explanation of the relationship you wrote above? Include wavelength and frequency in your explanation

Two types of wave sources Point Source One point that oscillates – Like a child bobbing in the pool. – Produce circular waves Plane Source An extended (rectangular) source that oscillates. – Produce plane waves

Diffraction Diffraction is the bending of a wave around a barrier – Consider a door cracked open, what shape does the light make? If it didn’t bend, it would be a straight column As you can see the light ‘fans out’ after it passes through the barrier

Ripple tank Ripple tank a way to show wave behaviors Point source Plane wave Angled Reflection Diffraction around a corner Single slit Double slit Doppler effect

Point Source Angled Reflection Plane wave Diffraction around a corner

Single Slit Doppler effect Double slit Your own:

DO NOW: 1. Which wave phenomena is exemplified by this picture? 2. As the wave propagates, explain what happens to the… -speed of the wave -the wavelength of the wave -the frequency of the wave - the amplitude of the wave HW: Castle Learning on Diffraction-Due tomorrow. Counts as a 10pt HW assignment Aim: How do we recognize various wave behaviors?

DO NOW: 1.Name two different media in this picture. 2.What happens to light as it passes from one medium to the other? 3.Offer an explanation as to WHY you are seeing what you see. HW: Blue Book Review for test- all of waves up to diffraction: pg Aim: What is refraction and how do we use it in every day life?

Refraction Refraction is the BENDING of a wave as is travels from one medium to another. Remember: a wave changes speed when it moves from one medium to another.

Index of Refraction The index of refraction is similar to the coefficient of friction. – It tells you how easily (quickly) light travels through a substance – It has no units – The symbol for index of refraction is n – The formula for the index of refraction is – c is the speed of light in a vacuum (3x10 8 m/s) – v is the speed of light in the other medium. – The index of refraction is ALWAYS GREATER THAN ONE!

Homework -Make sure lab is complete - finish packet Do Now: First page of packet (#6). AIM: How do we apply Snell’s Law when finding the index of refraction of a medium? Remember, Snell’s Law:

Using the Index of Refraction 1.In which medium does light move the fastest? 2.In which medium does light move the slowest? 3.In which two mediums will light have the same speed? 4.What is the speed of light in water?

Procedure: 1.Trace the block on a sheet of paper 2.Remove the block and construct a normal line close to the upper right hand corner 3.Using colored pencils, construct 5 incident rays at various angles between 15 o and 60 o 4.Replace the block, and using a ruler like the mirror lab, sight one of the incident rays through the block such that the ruler’s edge would run straight with the ray. Trace that ray and repeat for all 5 rays 5.Remove the block and connect the rays of the same color 6.measure the angle of refraction for each incident ray at the top of the block 7.Construct normal lines at each exit point and measure the incident and refracted angles. 8.Enter all angles in the data table 9.Graph sin θ 1 vs. sinθ 2 (what will the slope of this graph be?)

Do Now!

Finding the Index of Refraction Goals: The goals of this lab include to determine the index of refraction of the unknown block using a graph Background write a PARAGRAPH explaining how refraction works and what happens to all the parameters (speed, wavelength, frequency) of a light wave as it moves from one medium to another. Procedure based on the do now graph, what do we need to do to determine the index of refraction of a block?

Finding the Index of Refraction Refraction Block Top view Incident rays. 15 o increments Normal line Just like in the mirror lab, you will use a ruler to line up the ray while looking THROUGH the block. You line of sight needs to be at table level! You can use pins to help you line it up. Focus on ONE color at a time

Lab Requirements 1.Each person needs -A goal statement -Background PARAGRAPH on refraction and how it works -A procedure -Well organized data table (similar to the do now) -Graph -Slop calculation and percent error -Conclusion PARAGRAPH

Do Now Light is incident on a flint glass air boundary. The light enters the air at the following angles – 10 o – 20 o – 30 o – 40 o Using a ruler and protractor, find the refracted angle for each incident angle. You can use colored pencils to differentiate Flint glass Air

Dispersion

Polarization

Superposition

Constructive Interference

Destructive Interference

Double Slit Interference

Light as a wave

Light as a Particle

Wave Particle Duality

Energy of a Photon

Conservation of Mass/Energy

Homework Finish lab! Do Now: Draw a diagram of a pendulum and list what you could change about it. AIM: How do we determine which factors affect the period.

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Homework Finish lab! Do Now: Draw a diagram of a pendulum and list what you could change about it. AIM: How do we determine which factors affect the period.

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Presentation on theme: "Homework Finish lab! Do Now: Draw a diagram of a pendulum and list what you could change about it. AIM: How do we determine which factors affect the period."— Presentation transcript:

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