Maya plucks a guitar string and hears a sound. When she presses her finger on the string, the sound stops right away. What was making the sound before she touched it?

A student stretches a rubber band tighter across an open box and plucks it again. The rubber band now vibrates faster than before. What happens to the sound it makes?

Ben taps a drum gently, then hits the same drum much harder. The drumhead now moves back and forth a greater distance each time. How does the sound change?

A struck tuning fork looks completely still. When its tip is dipped into a bowl of water, the water splashes. What claim does this observation best support?

Lena taps one end of a long wooden table. Ana presses her ear against the other end and hears the taps clearly, even in a noisy room. What does this show about sound?

Two whales swimming far apart in the ocean call to each other, and each one hears the other's call. What is the sound traveling through to reach them?

A student puts an ear against a steel railroad rail and hears an approaching train before anyone standing nearby hears it through the air. Sound travels fastest through which kind of matter?

Astronauts working outside their spacecraft cannot hear one another shout, so they speak by radio instead. Why does shouting fail out there?

A xylophone has bars of many different lengths. When they are struck with the same force, the long bars vibrate more slowly than the short bars. What sound do the long bars make?

Sam taps a row of glass bottles with a metal spoon. Each bottle holds a different amount of water. The bottle holding the most water vibrates the slowest when tapped. How does its sound compare?

A marching band keeps playing at a steady level while Jordan walks farther and farther down the street. The music sounds weaker and weaker to him. What is changing about the sound he hears?

Ravi turns up the volume knob on a speaker without changing the song. How do the speaker's vibrations change?

A singer holds a low note, then sings a much higher note at the same loudness. What has changed about the parts of her throat that make the sound?

Sound needs matter, such as a solid, a liquid, or a gas, to travel through.

Ana blows across the open top of a long plastic straw and hears a note. She cuts the straw much shorter and blows across it exactly as hard as before. The air inside the shorter straw vibrates faster. How does the note change?

A sound's pitch can change while its volume stays the same.

Two students want to test whether a longer string has a lower pitch. They compare a short thick string with a long thin string. What is wrong with their test?

Kai claims that louder sounds are made by bigger vibrations. Which observation best supports his claim?

A team is designing earmuffs to make a noisy workshop quieter. The earmuffs must cost less than ten dollars per pair. Their best noise-blocking version costs thirty dollars. What is the problem with that version?

Ana hears her brother talking in the next room with the wooden door closed. What does the sound travel through on its way to her ear?