I made this toy before I made the lock, but forgot to post it up.
1. Empty, clean spice container (tall clear plastic one)
2. Small magnets (not too strong, round ones would work the best)
3. Corn Syrup
4. Plastic Vial with a rubber cap.
6. About a tablespoon of ferrous metal shavings ( http://www.instructables.com/id/EGPTPN17FFES1764M3/ )
Warning: Do this in a well vented area. Glue has toxic fumes (That's what I've been told).
Video below: I used magnets that were too strong, so only a small amount broke away from the fields.
Step 1: The only "Step"....
1. If you use a spice container with a pour/sift clip on lid, just pop that off.
2. Place the magnets inside the vial.
3. Take the rubber cap (from the vial) and glue it into the center of the spice container's cap.
4. While we let the glue dry, fill up the spice container about 85-90% with the corn syrup.
5. Add the ferrous shavings to the spice container's content (it'll sink in sort of a blob).
6. Place the vial on the rubber cap, make sure it's dry and secure. If it's not secure, use more glue around it.
7. Screw the lid onto the spice container. Shake up the container and you now have a "toy".
There's a video in the intro, but I used magnets that were too strong and only allow little amounts of shavings to let go (unless I use both hands to shake it). So in the video, only a few of the smaller sections came off and you can't even see them due to the quality of my camera up close. Anyhow, when you shake up the container you loosen up the shavings and capture several small air bubbles which all float around in slow motion. Looks cool to look at and watch.
Now all I need to do is (besides switching to weaker magnets) drill some holes into the cover and attach some LED's on the inside. Then waterproof around them to prevent leakage. I'm lacking LED's as of now, but I'll raid the basement in look for some later.