 Hi, my name is Ileana and I'm a librarian at the San Francisco Public Library. You may recognize me as the host for the STEM Challenge Yourself series, where SFPL librarians share fun and creative STEM projects for you to try at home. I'm really excited because today's episode is a super special one. We have a Teen Takeover. This summer, Youth Engaged in Library Leadership teens created STEM projects as groups for you to do at home using household items. Are you ready to try out this fun experiment? Let's go! I'll be your host for this STEM Challenge Yourself video. Today, Callie will be showing you a couple of musical instruments and how they work. First, she'll be showing you the bee hummer. Hi, I'm Callie and today I'm going to be showing you how to make two instruments, the bee hummer and the straw oboe. We're going to start with the bee hummer. It's a super fun toy that when you swing it around, it sounds like there's a swarm of bees nearby. For this, you are going to need a stapler, an index guard, a popsicle stick, two of these pencil top erasers, a wide rubber band, some string and some scissors. First, you're going to start by attaching the popsicle stick to the erasers. You want to put them on top, but if you have a big popsicle stick like me, you can cut it in half to make it work. Next, you are going to staple your index guard to the wood. If you have a bigger index guard, you can also trim it. Or next, you are going to take about two feet of string and attach it on to the popsicle stick. Tie it in a knot at one end of the popsicle stick. And last, you are going to attach the rubber band around the two erasers. Make sure you have the erasers on good so it doesn't come off. This might take a couple tries. Now you're going to swing it around. Do I hear a swarm of bees nearby? Okay, now let's talk about why that works. So with the bee hummer, when you swing it around, it forces the molecules in the air to interact with the rubber band. This creates the vibration. This is like a sound wave, and that's why it travels all the way to your ear. Like the vibration, sound waves are compressional pressure waves, and you can think about that in a slinky. When it moves back and forth, you can see the wave being passed through. Similar to the movement of slinky, a sound is created when an object vibrates, and so the molecules in the air force to interact and that travels all the way to reach your ear drums. Then your brain interprets this as sound. The index card also helps to amplify the sound by vibrating against the rubber band. Now I'm going to talk to you about the straw oboe. For the straw oboe, you will only need a straw and some scissors. So first, what you want to do is take your straw and flatten it out like this. Make sure it's really good and flat. And then you're going to take your scissors and cut two little triangles out. You want it to look like this, so it has these two pointy parts. Next, you're going to go in, you're going to flatten out one more time, and then you're going to put your lips around it and blow. You might have to flatten it a few times. So what's going on here? Like the bee homer, the straw oboe also works with vibration. When you blow through the straw, air is going through while there's also pressure building up on the outside, causing the straw to close. Once enough pressure builds up, it causes the straw to reopen, creating the vibration. Those also create the sound waves that reach all the way to your ear. You can change how the straw is like louder or quieter by making the straw longer or shorter or by blowing harder or softer. Thanks. Thanks, Callie. For more information about the STEM Challenge Yourself series, check out sfpl.org. Thanks for watching. See you next time. That's pretty cool. I like that you could learn about sound waves and have an instrument that you could use at home. I want to thank the teens that were part of this instrument making STEM Challenge. Our other STEM Challenge videos is part of Teen Takeover and the teens that were part of the Youth Engaged in Library Leadership Program with the San Francisco Public Library. For more info, tips and tricks about this video, our videos with our SFPL librarians and future Teen Takeover videos, be sure to check sfpl.org slash STEM Challenge and stay STEM-tastic. Bye.