April 22, 2016

Earlier this year, members of the WRAP Lab, Lexie Tabachnick and Joe Toscano, along with friend of the lab, Neil Bardhan, submitted an entry to this year’s Flame Challenge to answer the question “What Is Sound?”. The Flame Challenge is a contest organized by the Alan Alda Center for Communicating Science that challenges scientists to explain complex concepts to 11-year-old students. Written and video entries are judged by students in classrooms around the world.

We submitted an entry for the written response category, and although we did not win, our entry was judged to be one of the top 25 submissions! You can see the finalists and choose the winning entry here.

Here is our answer to the question “What Is Sound?”

Sounds are everywhere. Music, birds, babies crying… We can’t go anywhere without sound!

Sounds happen when something vibrates, meaning that it moves back and forth really fast. Think about music. When you press the keys on a piano, strings inside vibrate and create sound. The strings on the left vibrate more slowly, which creates low notes. The ones on the right vibrate more quickly, creating high notes. This difference between low and high notes is called frequency.

You can also change how loud the sounds are. That's called amplitude. If you press the keys gently, they're quiet. If you hit them hard, they're loud.

All sounds have a frequency and amplitude. Your ears are great at noticing this. In fact, cells inside your ear are arranged like keys a piano. Cells on one end detect low notes and cells on the other end detect high notes.

What about speech sounds? We hear thousands of words every day, but words aren’t just low or high notes, like music. How do we tell them apart?

Let’s create some sounds. Place your fingers on your throat. Say “baaa” and “paaa”. Try it a few times. Can you feel the vibration on your fingers? Did you also notice the puff of air that happens with “p”? It lasts longer than it does for “b”. This difference is one way we make different sounds when we talk.

Here’s another. Say “eeee” and “ahhh”. Don’t worry if people are giving you funny looks. This is for science! When you say “eeee”, your tongue is near the front of your mouth. When you say “ahhh”, it’s near the back. This is how we create different vowels.

By putting these sounds together we can make words. Now, you can use sounds to tell someone else what sound is!