Science at the Speed of Sound
First Draft: January 2008
Most recent update: October 2008
Introduction
The following learning objectives are taken from the Ontario and Quebec curriculum documents and synthesized for ease of use. Complete citations from both documents appear in the curriculum link section of the training binder.
Our goal is for the children attending Science at the Speed of Sound to understand:
v that sound is a form of energy
v that sound is caused by vibrations which are transmitted via sound waves
v that sound can travel through a substance
v how the human ear is designed to detect sound
v that sound can have potentially harmful effects in the world
v how some materials that absorb sound are used
Naturally, aviation is the twist given to our program which differentiates it from the program they would expect to receive at a science center or similar facility. Below is a list of aviation–related topics which form an additional layer of learning and help teachers relate science and technology to the real world:
v aircraft sounds (how they are made, what makes them)
v the evolution of aircraft design (and other inventions) to reduce the effects of noise and improve comfort for passengers and crew
v what happens to your ears in flight
v noise pollution from aircraft (and the industry response)
Construction in the Museum
Starting in the fall of 2008, the Museum will undergo major physical changes. The majority of the aircraft on the floor will be moved, a new group lobby as well as classrooms are anticipated. The locations noted in the program outline are to be used until the construction of the classrooms at which point the sound demonstration and activities will be relocated to the classrooms. All other portions will stay essentially the same with minor adjustments to be made to the script to reflect any changes in aircraft selection on the tour route required as a result of aircraft moves.
Section 1 – Introduction / Why come to the Aviation Museum to study sound?
Location: CF-104 (post-construction: CF-18)
Second Location for Two Group Scenario: BCATP
Approximate Duration: 15 minutes
Format: Q&A
Purpose: Establish a rapport with the group, capture their interest and set the tone for the program; reinforce the purpose of the program.
Begin with a general welcome to the museum (introduce yourself, quick review of rules etc…). Then ask the following types of questions (allow for student feedback, questions etc…):
o How many of you have heard an aircraft fly over head?
o Are they loud? Does it hurt your ears?
o Has anyone heard an aircraft up close? What kind of aircraft? Big or little?
o Are they only loud on the outside or are they loud on the inside too?
o Does it matter if airplanes are loud?
o Just how loud is an airplane? Is there a way to measure how loud they are?
Show decibel meter and explain that this is a device used for measuring sound. Turn it on and ask everyone to be quiet. On a large paper, record the sound level. Ask them to talk normally amongst themselves and record the number again. Ask them to clap their hands and yell (count them down for 5 seconds) and record the number. Go over the results with them. Reveal the chart of other sounds and read out some examples. Then ask how loud they think a jet aircraft would be compared to their sounds (twice as loud? three times?). Reveal the answer (a jet taking off is approximately 140 decibels).
Explain that there is a device called a decibel meter that can be used to measure sound. Show the decibel chart and where different activities rank compared to a jet engine.
In order to judge how much they understand about sound and hearing, ask the following types of questions:
o What part or parts of an aircraft makes noise?
o How does the sound get from that part of the aircraft to our ears?
Explain that next you are going do some experiments about sound and how our ears work. Before entering the classroom, explain to the teachers that the kids will need to sit in small groups at the tables and that one adult should sit with each group of kids if possible.
Section 2A – Sound Activity Stations
Location: Group 1 = RAF Café; Group 2 = H-68
(post-construction = Classrooms 1 and 2)
Approximate Duration: 45 minutes
Format: Activity Stations
Set up: Keep all activity materials on your work table. Group all materials so that each activity is separately identifiable.
Purpose: For the kids to experience that sound is a form of energy that travels in waves of vibrating air; that sound can travel through a substance and that it can be absorbed.
Explain that they are about to undertake some activities that will help them understand about sound.
Key instructions to kids:
· Work together in your groups
· Everyone will have a chance to try each station
· When finished an activity, please replace all the materials neatly in the center of the table for the next group and sit quietly so you know they are ready to rotate
· You will signal the group when it is time to rotate (approx. 5 minutes per station)
For each activity, hold up the various materials and ask what the group thinks they need to try to do with the materials. Make sure that everyone is clear about the question they are trying to answer (i.e. Does sound travel through water?) and the methodology. Do not take answers yet!
After all the activities have been explained, ask 1 person from each table to come up in an orderly fashion and retrieve the materials for their station. They may begin when they have their materials.
Keep a close eye on each group – circulate and help especially if there are not sufficient adults to have one at each station. Keep an eye on the time – give suggestions for further explorations to groups are done early and help slower groups catch up so that everyone can rotate at the same time.
Use the attached activity sheets to keep track of the materials for each station and for explaining the goal of each activity. Everyone should understand the question they are trying to answer at each station.
At the end, have the last group in the rotation, bring the materials back to your work table. Take a few minutes to go over the results – ask them questions (refer to questions on activity sheets) about their experiments and the results.
Section 2B – Hearing Demonstration
Location: Same as 2A
Approximate Duration: 15 minutes
Format: Interactive Demonstration
Purpose: To tie together the information learned in section 2A to understand how our ears hear. To explain what happens to them when we fly (why they pop, how pilots can lose track of up and down).
Begin by asking a few questions about the experiments to see if the kids understand the concept that sound is caused by vibrations, that sound is energy, that it can travel through things etc…
Now bring them back to an airplane flying overhead. Ask what the airplane is doing to the air (moving it). Ask what happens to the air when it moves (the air molecules vibrate and the vibrations travel in waves). Ask where they think the waves have to go for us to hear the sound (in our ears!).
Bring out the model of the ear. Point out if the outer ear and ask if anyone knows the name of that part of the ear (outer ear; pinna). Ask what they think that part does (traps the sound). If you want to hear more sound, you need more ear! (pull out big paper cone and demonstrate with a kid).
Ask if anyone knows another part of the ear that is considered part of the outer ear (point out the ear canal). What do we find in our ear canal? Earwax! The kids will laugh and think this is gross but you can explain that earwax is useful because it traps dirt and gunk and prevents us from getting ear infections.
Explain that the sound waves are trapped by the outer ear and travel down the ear canal to the next part of the ear (solicit the name and show it – the middle ear). When they get to the middle ear, the sound waves bump into something (solicit the name and show it – the ear drum). Remind the kids of the activity they did with the rice. Tell them that the cellophane stretched across the container was kind of like our ear drum. When the sound waves hit the cellophane, the rice bounced around (vibrated). Do we have rice in our ears? No! What do we have? 3 tiny bones (solicit the names and point them out – the malleus, the incus and the stapes). These bones help move the vibrations along into the next part (solicit the name and point it out – the inner ear).
The inner ear has a small curved tube (solicit name and show – the cochlea). Does anyone know what is inside the cochlea? Liquid! Ask the kids what happened when the sound vibrations hit the water in the experiment with the tuning fork and water tray (the water moves; waves). Explain that there are also tiny hairs that vibrate and these send nerve signals to the brain which are then interpreted as sounds.
Next ask what happens to out ears when we fly, (they pop). Ask if anyone knows why, (air pressure).
What is air pressure? What is air for that matter? (get a couple answers from kids) – get kids to say that air is all around us and air is always pushing in all directions. How can we prove that? Well, we can capture air….
Ask a kid to come up and capture air in a plastic bag.
Air is made up of a huge number of molecules and atoms (which are tiny tiny things) that are constantly in motion.
Ask another kid to come up and shake the molecule box.
Imagine millions and millions of these little molecules. Individually they don’t amount to much (do not weigh much or have much mass) but together they create air pressure.
If there is air pressing on us, why don’t we get squished? Because we have air inside us too so it balances things out.
So what happens when we are in an airplane and we take off? As we go higher up, there are fewer air molecules around us (more space between them). This causes the air pressure to drop. This means that there will be a difference in the pressure outside our bodies and the pressure inside our bodies. So, what does that have to do with our ear?
There is air inside us, including in our ears. When you are in an aircraft, and you are taking off, the pressure outside your ears drops. This creates an imbalance with the pressure of the air inside your ears. Luckily your body is prepared to deal with this – there is a part of your body called the Eustachian tube (a narrow tube that connects your ears and your nose) and this acts as a valve and opens up you can make it open by swallowing) to equalize the pressure – that is the “popping” sensation you feel. The reverse happens when you land.
Next explain that our ears have something else to do with flight. Ask if anyone knows what it might be, (get a couple answers from the kids).
Well, remember (refer back to model), the inner ear? There are 3 small loops above the cochlea called semicircular canals. These are filled with liquid and lots and lots of tiny hairs. This part of the ear is very important to our balance.
Ask for a kid to come up and demonstrate the next part (have him /her stay for next part).
When you move (start spinning the kid slowly), the liquid in your ears moves also. This movement sends a signal to your brain to say where your head is. What happens when you stop moving? (stop the kid – make sure they don’t fall down!). (get a couple answers from the rest of the class) – you stop but the liquid keeps going so your brain gets confused and you get dizzy! (thank kid – they can sit down).
Repeat while having the kids use the pop bottle of dyed water so that everyone can see it better.
For a pilot, as the aircraft is moving up/down, side to side etc… (roll, pitch, yaw), the liquid in the pilots ears sloshes around. Those tiny hairs in the semicircular canals detect the sloshing motion of the liquid and tell the brain what is going on. But, because something the sloshing keeps going even after the pilots’ head has stopped (the plane is in level flight), the pilot might get confused and think he is still turning when he is really straight and level. That’s why the instruments in a cockpit are so important to helping the pilot!
So, now we know that air moves in waves which make vibrations in our ears and allow us to hear. We also know why our ears “pop” during flight and what we can do (swallow to open Eustachian tubes). We also know how important our ears are for balance and why pilots have to rely on their instruments to make sure they are not being fooled by their body.
Ask if there are any questions.
Explain that next we are going to go to a special place in the museum to talk about how sound is absorbed.
Section 3: Reducing the Effects of Sound
Location: Hall of Tribute
Approximate Duration: 5 minutes
Format: Q&A
Purpose: Sound can have potentially harmful effects on the world. Loud sounds can damage hearing and effect animals by making it hard for them to communicate with each other which could put them in danger.
Explain that you are leaving the classroom to explore the museum’s collection and to see how aircraft relate to sound.
Bring the group to the Hall of Tribute and explain it is a special room designed to absorb sound. It designed this way so visitors who come here can have a quiet place to reflect on the efforts of the people who made contributions to the RCAF and to Canada.