Riding the Waves of Sound

Engage / Activator (approx. 5 minutes):

• This activity may affect students with hearing aids so you may want them to step out of the room briefly.
• For this activity you will need a couple of adults (the more adults, the more effective, but two including yourself will do). You will need your students, a computer with the speakers on (not blasting- just regular sound) and this website. Have everyone participating in the activity, including the adults stand up. Start with the lowest pitch which is 8kHz. When you hit the arrow, each pitch will play when you click it, for 2 seconds. With each pitch, have everyone stay standing if they can hear it. Announce that you are playing a new pitch before you hit play. You *may* choose to play eachtwice. When a person can’t hear the pitch, they need to sit. Keep going until nobody can hear one, that will be somewhere above 17 mHz, however, adults will start not hearing it somewhere around 14 or 15 mHz for the most part. However, most eighth graders will still be able to hear a few more pitches higher than that. The students won’t believe you can’t hear the higher pitches that they can hear which is why the activity works well to have adults in the room too.

Direct Instruction (10 minutes): 

• Today we are diving deep into sound. When do we use sound? A difference in pitch occurs when the frequency of the waves change. The higher the frequency, the higher the pitch. The lower the frequency, the lower the pitch.
• The wave height, or amplitude, affects the volume. When you turn your speakers up for to make sound louder, then you are making the amplitude bigger. When the sound gets quieter, the wave height gets smaller. As a review, sound waves are mechanical waves which means that they need matter to travel through. If there is no matter than sound cannot travel.
• It is suggested that the teacher ask students to come up to the board and illustrate amplitude, wavelength, and height as a review. Students may do this on a white piece of paper or on a small personal whiteboard if available.

Independent Investigation (30 minutes): 

• The instructor will need to divide the students in to four groups to complete the following activities on a rotation. Students will be at each station for approximately 5 minutes. Teachers may adjust the time based onthe needs of each group.
• Lab 1: Students will first wind the music box and listen to the music. Next they will wind it and hold the music box firmly against the whiteboard or the metal tray on the white board. Students should compare the sound from the first time they listened to when they held it up to the board. (Teacher note: The music should sound louder when they hold it up to the board because the matter is solid instead of the air which was a gas) The solid makes it easier for the particles to vibrate because they are closer together. This amplifies the sound.)
• Students will write down their observations and make their conclusions as to what they heard and why.
• Lab 2: For this activity the teacher will need to get 2 tuning forks. If your lab does not have one check with the music teacher. One sturdy plastic cup (clear) should be filled most of the way with water, leaving about a half inch unfilled at the top. Students will strike the tuning fork on the table, getting it to ring. Immediately after striking the fork,stick it partially in water. Have the students illustrate, describe, and explain what theysaw, on a piece of paper. (Teacher note: While the fork is making a tone, it is vibrating,therefore when it is placed in the water, it will spray water. This is caused by the sound vibrations. As mechanical waves, sound needs matter such as air or water to travel.
• This gives visualization so students can see sound waves move.)
• Lab 3: 5 -7 Cheap glasses (12 oz) real glass- all the same, a bucket of water or watering pot with water, metal spoon. Students will make a familiar song such as ABC, Three Blind Mice- they can pick the song. They will make the song with glasses filled with different amounts of water. They control the water. Explain that students will gently tap on the glasses to make the tones. Students will explain why the sound is different with different levels of water.
• Lab 4: At this station there will be a ping pong ball with about a 1 ½ feet of string taped to it. One student will hold the string so that the ball hangs down. Another student will strike the tuning fork on the table to make the tone and slowly move the fork toward the ball as the fork makes noise. What happens to the ball? Why? Explain using level three vocabulary such as vibration, sound waves, matter, etc.
• Lab 5: The teacher will decide which links students utilize for this section. There are three online interactives to choose from to review soundwaves:
• http://interactives.ck12.org/simulations/physics/violin/app/index.html - This interactive has two parts. The first part plays music and discusses why different instruments play the same note but have different tone The second part shows how different traits of a sound wave cause the volume or pitch to change. There is an information tab at the top of this section for further explanation.
• http://interactive.knowitall.org/interactive/nasa/sound/wave_traits.html This interactive further reviews waves and wave properties in general.
• Lab 6: If sound travels on average at a speed of 340 m per second, how long would it take to travel from school to your house? (Students will need to use a mapping app or website to determine the distance from school to home). If the sound was traveling under water, would it take longer or would it go faster when traveling?
• As students make their rounds they use the collective information that they have gathered through observations and the online interactives to draw conclusions about sound waves.

Formative Assessment (5 minutes): 
At the conclusion of this process, have students sit down but stay seated near their other group members. They are going to complete a disciplinary literacy strategy called Chain Notes (full instructions provided on PDF).

Chain Notes is a strategy that begins with a question printed at the top of a paper. The paper is circulated from student to student. Each student responds with one or two sentences related to the question and passes it on to the next student. Upon receiving the previous “chain of responses,” a student adds a new thought or builds on a prior statement.

The teacher can select his/her own statement or use this one for students to pass around: Some ways that we control sound are…:

Closure (5 minutes)- 
3-2- 1 is a strategy that aids reflection by providing a structure for students to summarize, organize and integrate what they are learning. When asked what they learned, students are often at a loss as to where to begin explaining their thinking. 3-2- 1 helps by giving them prompts to jump start the process of reflecting. The strategy may be used as an admit or exit ticket. It may also be used to promote reflective dialogue by small groups of students.

After a learning experience, provide students with prompts similar to the following:

 3 things I learned today

 2 things I found interesting

 1 question I still have

Full PDF is included for full directions.