## Waves and Sound

Vibrating Mass on a Spring
Pick up a mass and place it on the end of a spring and watch the mass bob up and down. Pull it off the spring and try placing a different mass on the end of the spring. Or use both springs and place different masses on each one of them. Ready to measure? Just click the Start button and the height of the mass, the velocity at which it is moving, and the time will all be measured and plotted on a graph. Values go by too fast? No problem with this Interactive - just drag a slider backwards across the graph and view height, velocity and time values at any point on the graph. As if that were not enough, you can also change the nature of the spring - changing both its stiffness and the amount of damping. This simulation is so realistic it is almost as if you are manipulating the real thing.

Grab a particle on a string and start wiggling it back and forth. Watch as the disturbance you create travels from particle to particle. Explore the result of wiggling more or less frequently or with a smaller or larger amplitude. Change the amount of damping effects and other variables. You'll have so much fun with Slinky Lab that you might forget that you're learning physics.

The Physics Classroom thanks their friends at Nerd Island Studios for contributing this Interactive to the collection.

Simple Wave Simulator
Whether seen in a science museum or inside a physics classroom, everyone is intrigued by a wave machine. One can watch and observe the periodic motion of a mechanical wave machine in amazement without knowing that 30 minutes just passed by. Prepare yourself because you are about to observe a virtual wave machine ... only now you (not the museum official or your teacher) are in control. You can set it vibrating at any frequency and any amplitude you wish. You can even view it simulating a sound wave. Watch it vibrate in slow motion. Watch it in fast motion. Watch it in real time. And watch the clock because you're going to be so captivated that you might be late for your next class.

Standing Wave Maker
If you have ever seen a standing wave demonstration, then you have seen the definition of groovy (excuse the 80s term). And groovy is what you will see when you open this simulation. Make standing waves from several pre-set conditions or set the conditions yourself. View two waves traveling in opposite directions and the standing wave pattern that results from their interference. Don't forget to say Groovy!

Thanks to our friends at Nerd Island Studios for contributing a little bit of groovy to our Physics Interactives collection.

Beat Patterns
If you have ever tried to tune an instrument, you likely used the phenomenon of beats. Or if you've observed the orchestra attempting to tune their instruments to one another, you likely observed them utilizing beats. Just exactly what is the concept of beats? And what physics is involved in beats? In this Interactive, you will use two virtual tuning forks to explore the answers to these questions. Give them a tap, set them into vibrations, and observe the result.