Sound Part 1

Another form of energy is sound Vocabulary words you should know and listen for while watching Bill Nye are: Sound (duh!) Vibration Pitch Absorption

Bill Nye Quiz Questions A(n) __________ is an instrument that visually shows the changes in a varying current or frequency of sound waves. a. laser b. microscope c. oscilloscope d. telescope Which of the following is an important term related to sound and music? a. frequency b. pitch c. vibration d. all of the above A ________ creates sound by making air molecules vibrate at certain frequencies and can be used to fix the sound of an out-of-tune instrument. a. divining rod b. rhythm spoon c. treble staff d. tuning fork How many quarter notes make up a half note? a. 1 b. 2 c. 4 d. 6 5. ___________ discovered that the octave had a ratio of two to one and used the idea to develop the musical scale. a. Galileo b. Plato c. Pythagoras d. Socrates

Bill Nye Quiz Answers A(n) ____________ is an instrument that visually shows the changes in a varying current or frequency of sound waves. C. Oscilloscope Which of the following is an important term related to sound and music? D. All of the above A ________ creates sound by making air molecules vibrate at certain frequencies and can be used to fix the sound of an out-of-tune instrument. D. Tuning fork How many quarter notes make up a half note? B. 2 _________ discovered that the octave had a ratio of two to one and used the idea to develop the musical scale. C. Pythagoras

What is Sound? Turn to page 1 in your books (draw glasses at the bottom of the page then read) Turn to page 2. If a tree falls in a forest and no one is there, does it make a sound? Why or why not? Let’s talk about it…what do you think? We’ll get back to the answer at the end of the lesson Sound is a form of energy caused by vibrations. Vibrations are the rapid back and forth movement of molecules. Sound energy is transmitted by vibrating an object.

How sound happens Let’s write down the 8 steps how sound happens Pluck the string The string vibrates Molecules around the string vibrate This causes more molecules to vibrate The vibration continues to travel through the molecules The vibration reaches your ear Your eardrum and other bones vibrate This tells your brain you’ve heard a sound

Choose an instrument that does not have strings Choose an instrument that does not have strings. How does it produce sound? For instance: Instrument: Drum How it produces sound: Strike the drum. The drum vibrates. This vibrates molecules which travel to your ear. Your ear bones vibrate and you hear a sound. Instrument: Recorder How it produces sound: You blow into the recorder making a vibration, this vibrates molecules, your ear bones vibrate, you hear the sound.

Tuning Fork Turn to page 3 Have you seen one of these before? What does it do? Let’s see if we can get it to make a sound What will happen if I place the tines in water? What if I exert more energy upon the tuning fork and place it in water again? Why? The tines vibrate, which vibrates the water. What will happen if I only place the handle of the tuning fork in the water after hitting it? Why? The handle is not vibrating, so it will not vibrate the water. How does sound travel? Sound travels in a wave.

Sound travels in waves We are going to see how a slinky can be used to show sound waves https://www.youtube.com/watch?v=_vYYqRVi8vY https://www.youtube.com/watch?v=4GBBSomUY90 Let’s try it, too Draw this in your book

How does the Slinky relate to the Molecule Model? The coils of the slinky actually represent the molecules in the air. As sound waves travel through air, the molecules compress and stretch apart just like the coils of the slinky Let’s draw a group of molecules close together (these are compressions), when they are stretched apart, they are rarefactions Let’s add the sound wave. The wave is up high (crest) when the molecules compress and is down low (trough) when they rarefract. The distance from one crest to another or one trough to another is known as one wavelength.

Circle Model Here’s another model to show you how sound waves travel. I need 2 volunteers I need one person to sit down on the floor and one person to stand on a chair Remind me to take off the microphone  I’m going to stand in the center of the room…and talk Raise your hand if you can hear me Even though I was only talking in one direction, how come everyone could hear me? Sound travels in all directions from its source. Let’s draw the circle model

In 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 vibrate. This causes the molecules to vibrate, and those vibrations spread out in all directions from the source. If the vibrations in the air reach your ear, you will hear the sound. However, even if you are not there, the vibrations still exist, so the sound still occurs. Fill your answer in on page 4

Since we talked about water in glasses… https://www.youtube.com/watch?v=_b-7P-XsnUI https://www.youtube.com/watch?v=gzf9hITzuOM

And strings on a guitar https://www.youtube.com/watch?v=ERjE22bwFcA https://www.youtube.com/watch?v=nM0xo1xZtP0