Spaghetti Submarines

Science concepts…

• Buoyancy
• Density
• Chemical reactions

The situation…

They’re trapped in the bottom of the preform…the spaghetti. And you want to get them out. The problem is that they are buried under a column of water and you have to retrieve them without emptying the water out. Daylight’s burning, so get to work.

Materials…

• 1 preform
• 1 small baggie with broken pieces of spaghetti
• 1 box of sodium bicarbonate power (baking soda)
• 1 bottle of acetic acid (vinegar)
• Water

Hints…

1. Spaghetti does not float in water so you are going to have to figure out a way to raise it from the bottom of the preform to the top so you can pluck it out.

2. Sodium bicarbonate, also known as regular old baking soda, will dissolve in water. When acetic acid, also known as regular, old, distilled, white vinegar, is added to this baking soda solution, carbon dioxide is released.

3. Carbon dioxide gas adheres or sticks to the sides of objects that it comes in contact with, like spaghetti, to name a random example.

4. Carbon dioxide is a gas less dense than water so it floats to the surface of the preform.

A possible solution….

1. Open the small plastic bag and empty the small, broken, pieces of spaghetti into the bottom of your preform and cover it with half of a container of water. Observe what happens. Nothing much so far, it’s just spaghetti in water.

2. Now add one, solid, ounce of baking powder to the water and, covering the open end with you hand, tip the container back and forth to mix it into a solution. Again, observe what happens. Still, not much. Hang in there; it will get really interesting in a minute.

3. Now add 3-4 ounces of vinegar to the baking soda solution. This will cause a lot of fizzing when the vinegar and baking soda start to react and the solution starts to look like clear soda pop or soda water. Now observe what happens to the spaghetti.

The science behind It…

When the baking soda and vinegar are mixed together, carbon dioxide gas is produced and released from the solution. Because the gas is less dense than the surrounding liquid, it rises to the top of the container. If there happens to be something to hang onto on the way up, the gas molecules grab onto it. As the carbon dioxide gas bubbles accumulate on the surface of the spaghetti, it becomes more buoyant. (Kind of like putting life jackets on the pasta.) When the spaghetti gets enough gas molecules hanging onto it, becoming carbonated spaghetti if you will, it is less dense than the surrounding water and starts to rise toward the top of the container. When it gets to the top, the gas is released into the room; the spaghetti suddenly becomes more dense than the water and sinks to the bottom to pick up more gas molecules. This whole process of picking up and loosing gas molecules can go on for an hour or more. Better than reruns on TV.