I started by reading Squeak! Rumble! Whomp Whomp Whomp! by Wynton Marsalis.
Then we talked about sound and different sounds we hear during our day. I also brought along a non-fiction book about sound that had a picture (ok, an illustration) of sound waves and we talked about how sound makes waves and makes things move.
I had stretched a balloon over a large plastic bowl and I put some salt on the balloon. Then I invited the kids to make loud sounds near the balloon to see if the salt would move. And, yay us, it did bounce when we made loud noises near it. I had the kids tap sticks near the bowl, but I'm sure other versions of noise-making would work as well.
Then we went to the stations:
1) The Cup Telephone
The simplest and somehow the most popular, I used two paper cups and some string and made an old-school string telephone. One little boy was just fascinated by it and his mother asked me "why does it only work if the string is taut?" so it was science learning for everyone!
2) The Wire Hangers
Because life is all about ups and downs, the same table that held the most popular telephone cup also held the least popular wire hanger activity. Tie a hanger to some string, wrap the ends of the string around your index fingers, put your hands over your ears, and bang the hanger into things to hear what it sounds like. You can see the most adorable child ever doing this experiment here. I tried to encourage kids to do it by doing it myself, but I guess no one wanted to look like a weird lumbering hanger-nosed elephant so most kids stayed away. Sigh.
3) Quiet or Loud
Benefit of having a baby at home: lots of formula containers. I put out several containers as well as a plethora of random small items. The kids put the things into the containers, put the lids on top, and shook. I asked them to say which was loud, which was quiet, and which was their favorite. Honestly, shaking things up is their favorite.
4) The Sound of Beans
I had several different sizes and kinds of containers and about a cup's worth of beans. The kids poured the cups into the different containers and listened to the sounds it made. Simple, but fun.
5) Make a Kazoo
I rarely do crafts during Preschool Lab - I prefer to make it a time of exploration - but this one was too good to resist (and I didn't have enough boxes for a rubber band guitar station). There are a lot of different ways to create these kazoos, but they all take paper tubes, waxed paper, and rubber bands. I ended up basing our craft on this set of instructions.
There were lots of good ideas here, like the model eardrum part that I used at the beginning, but I didn't get a chance to use them all because of time/available materials/point at which I started planning. It was a good session - just be ready for it to get a little loud. :-)