 Hello, my name is Vinnie and I am a librarian at San Francisco Public Library. For today's STEM challenge, we will be making balloon racers. But first, does everybody know what STEM means? Just in case you don't, STEM is an acronym where every letter stands for a word. In this case, science, technology, engineering, and mathematics. So how is this project STEM? Well, this project explores physics, using Newton's third law of motion to race our balloons. Newton's third law of motion states that for every action, there is an equal and opposite reaction. And in this case, our action will be the air escaping from the balloon and the reaction will be the balloon traveling in the opposite direction. So now that we have those concepts down, let's get started. First we will gather our materials. You will need a binder clip, some string, a pair of scissors, some tape, a balloon, and a straw. Now our first step is to measure out at least eight feet of string. So once you have your string cut, you will tape one end very securely to a wall or have a friend or family member to help you hold it. I'm going to let my friend here today. Next you will take the other free end of your string and thread it through your straw. So here's your straw. Once you have the straw or the string through your straw, set this aside and then blow up your balloon. Once you've filled the balloon as much as you like, you're going to secure it with the binder clip. So that the air does not escape yet. Then you will tape this balloon to your straw, making sure that the opening of the balloon faces away from your wall or friend. Right, so once you have your balloon taped to the straw, you're going to pull your string so that it is straight and parallel or even with the floor. And when you're ready, you're going to release the binder clip and watch your balloon go. And there you have it, our balloon racer. So to make this really a race, you can cut out another piece of string and make another one of these racers and challenge a friend. So how do you think you can get the balloon to go faster? Maybe with more air, less air, with different sized balloons? Why don't you try it out now that we've completed our project, the balloon racer. Thank you so much for joining me here today. And if you enjoy working with physics, some of the careers that are available to you are things like mechanical engineering, vehicle safety technician, or a physicist. And if you enjoy these STEM projects, please check out more of our STEM challenge videos in our playlist on the San Francisco Public Library YouTube channel. And if you'd like to read more about physics and the science of motion, please visit your local library and ask a librarian for some book recommendations. Or check out the link below for our suggested reading titles list. So thank you again and have fun.