Home orchestra

Find the best loudspeaker among your household items!

Difficulty:
Danger:
Duration:
20 minutes

Safety

  • Carefully review the general safety advice on the back of the box cover before starting the experiment.
  • Read the “Working with Batteries” section of the safety guidelines carefully before proceeding.
  • Do not let children under 8 years old handle small magnets.
  • Disassemble the setup after the experiment.

Step-by-step instructions

physics-microphone-project_iks-s-01

Let’s walk around the house and examine how well various household objects can work as a speaker. In the kitchen, for example, you can play with a pot, mug, or even a bottle. Use the setup from the DIY microphone experiment, and attach the magnet to the bottom of an object of your choice. Now, turn on the sound. If you’re looking in your room, try a pillow, tabletop, or book. Attach the magnet to your chosen item and play music. Which object is the prime contender in the competition for best speaker?

Disposal

  • Dispose of solid waste together with household garbage.
  • Dispose of used batteries in accordance with local regulations.

Scientific description

Let’s recall how sound is generated in the speaker. Electric current flows through the coil, constantly changing directions and thus attracting and repelling the magnet situated nearby. The magnet vibrates and, since it’s attached to the bottom of the speaker (an object of your choice), it causes the bottom of the speaker to vibrate as well. This vibration pushes the adjacent portion of air, which in turn pushes the next portion of air, and thus this push propagates through space. Ultimately, moving air reaches our ears, which is how we hear sound.

How come some speakers are good at transmitting sound, while others aren’t? One important factor is the material the speaker is made of. Once generated by the magnet’s vibrations, the oscillations travel through the air. Soon enough, they bump into the wall of your creative household speaker and are reflected from it. That is, the air pushes the wall of the speaker, which begins to vibrate and push the air as well. Depending on the material the speaker is made of, it either picks up the vibrations (solid yet flexible materials) or mutes the vibrations (soft and amorphous materials), thus amplifying or damping the initial sound that reached the speaker’s wall.