Sprinkle salt onto the plastic wrap. Then, connect the speaker to the cell phone, play a song, and watch the salt move to the music!
Troubleshooting: If the salt isn’t moving, first try increasing the volume. If it still isn’t moving, try moving the plastic wrap closer to the speaker by shortening the distance between the top of the popsicle sticks and the speaker.
Optional: To see the salt more clearly, try dyeing it with food coloring! Simply combine salt and one or two drops of food coloring in a sandwich bag and shake the bag until fully mixed.