What is Sound?

If a tree falls in a forest and no one is there, does it make a sound? Why or why not?

Sound Sound is a form of _______ caused by _________. Vibrations are __________________________ ____________________. Sound energy is __________ by ________ an object. energy vibrations the rapid back and forth movement of molecules transmittedvibrating

Demonstration: Stringed Instrument How sound happens: 1. Pluck the string. 2. The string vibrates. 3. Molecules around the string vibrates. 4. This causes more molecules to vibrate. 5. The vibration continues to travel through the molecules. 6. The vibration reaches your ear. 7. Your ear drum and other ear bones vibrate. 8. This tells your brain you’ve heard a sound.

Sound Choose an instrument that does not have strings. Explain how it produces sound: Instrument:______________________________ How it produces sound:____________________ _______________________________________

Sound Examples: Drum: You strike the drum, the drum vibrates, this vibrates the molecules, your ear bones vibrate, you hear sound. Recorder: You blow into the recorded creating a vibration, this vibrates the molecules, your ear bones vibrate, you hear a sound.

Sound Examples: Piano: You press the key, a hammer strikes the string which vibrates, this vibrates the molecules, your ear bones vibrate, you hear a sound. Trumpet: You vibrate your lips and blow into a tube, this vibrates the molecules, your ear bones vibrate, you hear a sound.

Demonstration: Tuning Fork Tines in WaterHandle in the waterWhy? The tines vibrate the water and cause it to move – possibly spray out of the pan. Nothing happens. The handle it’s not vibrating.

How Does Sound Travel? Sound ______ in a _____. travelswave

Demonstration: Slinky Model

Explanation: Molecule Model

How Does Sound Travel? Demonstration: Circle Model Can the people in front of you hear you talking? Can the people on the right or left hear you talking? Can the people behind you hear? Can the person below you on the floor hear? Can the person standing above you hear? yes

Sound Who could hear you talking? Why? Why could everyone hear you talking? Everyone in the room Your mouth (the sound) was only pointed in one direction. Sound travels in all directions from the source.

Sound Conclusion: If a tree falls in a forest and no one is there, does it make a sound? Why or why not? When the tree hits the ground, it causes the ground to _______. This causes the _________ to _______, and those vibrations spread out in ___________ from the source. If the vibrations in the air reach your ____, you will _____ the sound. However, even if you are not there, the vibrations still _____, so the ______ still occurs. vibratemolecules vibrate all directions earhear existsound

Sound Experiments Rubber Bands: Stretch each rubber band approximately six inches wide and plunk it. Rubber BandObservation Thickest Band Thick Band Thin Band Thinnest Band

Sound Experiments Paperclips: Hold the paperclips with the spiral on the desk and pluck the upper end. PaperclipObservations Small Paperclip Large Paperclip

Sound Experiments Vocal Cords Gently place your fingers on the front of their throat and recite the alphabet. Try varying your speed, pitch, and volume. SpeakingObservations Regular Voice Change Speed Change Pitch Change Volume

Sound Experiments Wire Hangers: Wrap the string around the index finer of each hand, put your index fingers in your ears, and hit the wire hanger again a chair or desk. Try changing the length of the string by wrapping in more or less around your fingers. Try hitting the wire hanger against different surfaces such a chairs, desks, tables, the floor (but no people)

Sound Experiments Wire HangerObservation Hanger Change Length Change Surface

Sound Experiments Yo-yos: Unwind the string from a yo-yo and hold the plastic end of the yo-yo next to your ear. Have a partner pull the string tight and pluck it. Try varying the locations the string is plucked by going closer to and farther from the plastic end. Also try pinching the string and pulling it through your fingers. Try varying the speed with which the string is pulled.

Sound Experiments Yo-yoObservation Pluck String Change Location Pull String Change Speed

Sound Experiments Balloon and Stereo Hold the balloon up against the speaker of the stereo while the music is playing. BalloonObservations Held on Speaker

Sound 1.What did all the objects have in common while they were producing sound? 2.What did you observe about the rubber band? They were vibrating. They vibrated when plucked to make sound. The differences in thickness affected their pitch. We’ll discuss pitch in more detail later.

Sound 3. What did you observe about the paperclip? 4. What did you observe about your vocal cords? They vibrated against the table to make sound. The larger and smaller one sounded different. My throat vibrated as I talked. The vibrations changed when I changed pitch, speed, or volume.

Sound 5. What did you observe about the wire hanger? Why? The hanger vibrated as it hit the chair and made sound. However, the sound in my ears through the string was much louder than if I just listened to someone else do the experiment. The string acts as an amplifier.

Sound 6. What did you observe about the yo-yo? The string vibrated when pluck or pulled to make the sound. The sound was much louder near the end of the yo-yo than the end of the string. The sound changed depending on where the string was plucked.

Sound 7. What did you observe about the balloon and stereo? I felt the vibrations of the music through the balloon. I could feel the different beats of the music as they changed.

Pitch _____ is a measure of ____ or ____ a tone sounds to your ear. Pitch depends on the _________ of the ____________. Frequency is ___________________________ ___________________________________. Pitchhighlow frequency sound waves the measure of the number of waves that pass in a given amount of time

Pitch Low FrequencyMiddle Frequency High Frequency ________ Frequency=_____ waves=_______ PitchGreaterMore Higher

Pitch Low PitchMiddle PitchHigh Pitch

Demonstration: Bicycle Card and BicycleObservation What created the sound? Wheel turns Faster Wheel turns slower

Demonstration: Talking Tapes Talking TapesObservations What created the sound? What phrase did you hear? What happens when it’s played faster? What happens when it’s played slower?

Demonstration: Musical Instruments InstrumentObservation Drums Ukulele Recorder Chimes _______, ______, _______=______LongerLargerLooserLower _____=____ or ____ Pitch High Low

Pitch Experiments Rubber Band and Textbook Stretch a rubber band around the width of a textbook. Place two pencils under the rubber band, one near the left and one near the right edge of the cover. Pluck the string and not its pitch. Place a finer one inch from the right pencil. Predict how the sound will change. Pluck the rubber band between your finer and the left pencil. Listen to the pitch. Were your predictions correct? Repeat the process for the entire length of the rubber band.

Pitch Experiments Rubber Band & Textbook Observations Entire Rubber Band 1 inch 2 inches 3 inches 4 inches 5 inches 6 inches 7 inches 8 inches

Pitch Ruler Hold ruler firmly against a desktop with 2 inches on the desk and 10 inches in the air. Strum the free end. Observe the pitch. Repeat the process for the entire length of the ruler with 4 inches on and 8 off, 6 inches on and 6 off, 8 inches on and 4 off, and 10 inches on with 2 off.

Pitch RulerObservations 2” and 10” 4” and 8” 6” and 6” 8” and 4” 10” and 2”

Pitch Band Instrument Stretch the end of the rubber band up and over the end of the ruler. Place your finger at the 2 cm mark and pluck the rubber band. Listen to the pitch. Repeat the process placing your finger at the 4 cm, 6 cm, and 8 cm marks and listening to the pitch.

Pitch Band InstrumentObservations Finger at 2 cm Finger at 4 cm Finger at 6 cm Finger at 8 cm

Applying what you’ve learned Use what they have learned about pitch to answer the following questions about human vocal cords. 1.How do we produce sounds? Air passes by your vocal cords causing them to vibrate.

Pitch 2. Why are some voices high while other are low? How would the vocal cords look different for a high voice versus a low voice? 3. How can we change the pitch of our voice? A high voice has tight, short, thin vocal cords. A low voice has long, thing, loose vocal cords. To make a high pitch, we stretch our cords thin. To make a low pitch, we compress our cords to make them thicker.

Mini Quiz Rand the following glasses filled with different amounts of water from the lowest pitch to the highest pitch. Why?

Mini Quiz B,C,A,D. B is the lowest pitch, because it has the most water. It is a “longer” or “larger” amount of water, so it is lower. D is the highest pitch, because it has the least amount of water.

Palm Pipes How do palm pipes work? What makes the sound? How is the length of the palm pipe related to its pitch? What was your favorite palm pipe song to play? Why?

Volume Have you ever placed your hands over your ears because something was too loud? When?

Volume Volume is the _________ or ________ of a sound. Volume depends on the ________________ used to produce the sound. You use a lot more energy to ____ than you do to _______. loudnessintensity amount of energy yell whisper

Volume If you want to play a musical instrument loudly, what do you need to do? Piano:________________________________ Guitar:________________________________ Drum:________________________________ Trumpet:______________________________ Volume=____ or _____ pound the keys strum the strings hard Hit the surface hard Blow hard into the mouth piece softloud

Volume Think about it Think about the gym. What are the floor, walls, and ceiling made of? Think about the library. What are the floor, walls, and ceiling made of? Wood, bricks, cement, tile, etc. Carpet, wood, fabric, etc.

Volume Why do you think they are made of different materials? What purposes do the room server? How is the sound involved? Gym:____________________________________ __________________________________ Library:__________________________________ __________________________________ Sound waves can be _________ off surfaces or _________ by them. A gym is noisy. It is used for assemblies, PE, etc. A library is quiet. It is used for classes, studying, and reading. reflected absorbed

Volume Absorbed Absorption is __________________________. Certain materials “soak” up ______ like a sponge soaks up water. To keep areas ______ (like libraries), certain materials are placed in the room to ______ noise. Examples of sound absorbing materials:_____ _____________________________________ the ability to take in or dampen sound quiet absorb carpet, fabric, furniture, insulation, Styrofoam, cotton

Volume Reflected If sound is ________ from an object, we hear an _____. In a large auditorium (like gyms), sounds are ________ from surfaces like ______________ _________. This reflection is known as ____________. reverberation echo reflectedtile, brick, metal, and wood loudness

Volume Too much ____________ is unpleasant, but a little gives sound its _______. Acoustical Engineers try to design buildings with _________ and _________ materials the help the sound ______ and still control ____________. reverberation fullness reflecting absorbing travel reverberation

Speed of Sound Sound travels differently in different materials. Study the chart below to see if you can identify any patterns.

Speed of Sound Sound travels ____ through a ____. Example:______________________________ _____________________________________ Sound travels ______ through _____ and _____. Example: _________________. Sound does not travel in a _______. A _______ is a place with _____. fastsolid The sound of a dental drill is clearly transmitted through the bones of your skull slowerliquid gases Talking under water vacuum no air

Speed of Sound Why can’t sound travel in a vacuum? _______________________________________ _______________________________________ _______________________________________ There is no ___ in _____; therefore, no ______. You pluck the string, the string vibrates, but there are no air molecules to carry the vibration to your ear, so there is no sound. airspace sound

Speed of Sound If there is no sound in space, how do astronauts communicate?___________________________ _______________________________________ Think about space movies you have seen recently. Are they accurate? Why or why not?___________________________________ _______________________________________ _______________________________________ _______________________________________ They have radios inside their helmets, and there is air inside the helmet. Usually no. There is no air in space, so there is no sound and no fire. The explosions in movies would not be nearly as spectacular without the flames and loud noises.

Rainsticks How do rainsticks work? What makes the sound?_______________________________ _____________________________________ How do the size and weight of the items you tested relate to their pitch?________________________________ _____________________________________

Rainsticks What material(s) did you choose to permanently put in your rainstick?______________________________ _____________________________________

Battle of the Bands What materials did you use to make your instrument?_____________________________ _______________________________________ How is your instrument played? How does it make sound?____________________________ _______________________________________ What was the name of your band?___________ What song did your perform?_______________