Floating+Ketchup+Experiment

What you will need: A 1 liter plastic bottle Ketchup pack from a fast food restaurant Salt (using Kosher salt helps keep the water from becoming foggy) What to do:
 * 1) Remove any labels from the bottle and fill it all the way to the top with water.
 * 2) Add a ketchup pack to the bottle.
 * 3) If the ketchup floats, you're all set - go to step 4. If the ketchup sinks in the bottle, go to step 5.
 * 4) For the floating ketchup pack simply screw the cap on the bottle and squeeze the sides of the bottle hard. If the ketchup sinks when you squeeze it, and floats when you release it, congratulations, you're ready to show it off. If it does not sink when you squeeze it, try a different kind of ketchup pack or try a mustard or soy sauce pack.
 * 5) If the ketchup pack sinks, add about 3 tablespoons (45 ml) of salt to the bottle. Cap it and shake it up until the salt dissolves. (Kosher salt will keep the water from getting too cloudy, although it will usually clear up over time if using regular table salt.)
 * 6) Continue adding salt, a few tablespoons at a time until the ketchup is just barely floating to the top of the bottle.
 * 7) Once it is consistently floating, make sure the bottle is filled to the top with water, and then cap it tightly.
 * 8) Now squeeze the bottle. The magic ketchup should sink when you squeeze the bottle and float up when you release it. With some practice you can get it to stop in the middle of the bottle.