AMASE: Sound Energy

[Guelph Physics logo, music.]

[Joanne standing in front of a blackboard.]

Joanne: On today's episode of Ask Me Anything Science Edition we have a question from grade 5 student Sophie in Guelph, Ontario. 

[Cut to girl wearing a mask in a classroom.]

Sophie: My name is Sophie I'm in Grade 5 and I was wondering um what sound energy would convert to or like how it would convert.

[Cut back to Joanne in front of the blackboard.]

Joanne: Such a great question Sophie. As you know sound is a form of energy which means we can turn it into other types of energy through different processes. For example, there is a process happening right now in your head that's turning sound energy into electrical energy.  

[Cut to animated ear diagram, showing parts of the inner ear.]

Joanne: Sound travels in waves and when it reaches your ear it travels down the ear canal to the eardrum which is a small thin stretch of tissue. The sound waves make the eardrum vibrate or move back and forth which means the eardrum is turning the sound energy into the energy of movement or kinetic energy. These vibrations get passed along through some tiny bones to the cochlea which is a structure that looks like a tiny snail that's full of fluid. The vibrations create waves inside the fluid which makes tiny hairs in the fluid dance around. The dancing hairs release chemicals which then create an electrical signal in the nerve cells nearby and it's those electrical signals that get sent to the brain to get interpreted as the sounds we hear. 

[Cut back to Joanne in front of the blackboard.]

Joanne: So, we are constantly converting sound energy into electrical energy in our heads. Here's another fun example...

[Cut to Mara sitting on the couch, clapping. The light beside her comes on. She claps twice more, the lights go off.]

[Cut back to Joanne in front of the blackboard.]

Joanne: Is it magic? Nope! The lamp is plugged into a device that turns sound energy into electrical energy. It's got a built-in microphone that turns sound into an electrical signal that activates a switch and turns the light on. When Mara claps again it activates the switch to open and the light turns off. 

Now one last example, in case you're wondering whether sound can be turned into any other form of energy other than electrical. 

Did you know that in medicine sometimes doctors use sound energy to treat kidney stones?  

[Cut to treatment office where a person is lying down on their stomach with their shirt off. An ultrasound machine is being used by another person to treat their kidneys.]

Joanne: If the kidney stones get a bit too big doctors will focus sound waves into the patient that are strong enough to actually break the stones up into much smaller pieces that are then easier to get rid of. 

[Cut back to Joanne in front of the blackboard.]

Joanne: Imagine getting blasted by strong sound waves as a form of treatment! Pretty cool right ? 

Thanks for your great question Sophie and thanks for watching Ask Me Anything: Science Edition!