Dancing Spaghetti - Experiment 1

Spaghetti is denser than water and, therefore, sinks when placed in water. When spaghetti is placed in a solution of baking soda and vinegar, the spaghetti rises to the surface due to the carbon dioxide gas that adheres to it. When the spaghetti reaches the surface, the gas is released, and the spaghetti sinks again.

Materials Substitutions
1 1000-mL beaker 1 glass mixing bowl
10 g sodium hydrogen carbonate 3 Tsp baking soda
45 mL 3% acetic acid 4-5 Tbsp vinegar
10 2-cm pieces of vermacelli
water

Procedure
1. Fill a clear container 3/4 full with water. Add the sodium hydrogen carbonate (or baking soda) and stir to dissolve.
2. Break the vermicelli into 2-cm, or 1-inch, pieces and add them to the container.
3. Add the acetic acid (vinegar). If the vermicelli does not begin to “dance” after a few minutes, add more sodium hydrogen carbonate and acetic acid.
4. If possible, substitute raisins or mothballs for the vermicelli.

Teacher’s Notes
1. Vinegar (HC2H3O2) is a 5% solution of acetic acid. It reacts with baking soda, sodium hydrogen carbonate (NaHCO3), to produce a carbon dioxide gas (CO2) and sodium acetate (NaC2H3O2). The reaction can be written as follows:

NaHCO3 (aq) + HC2H3O2 (aq) ——> CO2 (g) + H2O (l) + NaC2H3O2 (aq)

Bubbles of carbon dioxide gas adhere to the surface of the spaghetti. The result is that the sum of the density of the spaghetti and the gas is less than that of the water solution. Thus, the pieces rise to the surface. Many of the bubbles are released at the surface, and the density of the spaghetti becomes again greater than that of the solution. Thus, the spaghetti sinks. Children’s “water-wings” operate on the same principle by adding to the volume of the child without increasing the mass considerably.

2. The amounts of baking soda and vinegar are approximate and depend on the size of the container used. If a larger container is used, increase the amount of baking soda and vinegar appropriately.

Extensions
1. Raisins or mothballs can be used in addition to, or in place of, the spaghetti. Remember to make provisions for solids be placed in the trash instead of your sinks!!

2. Add a drop of food coloring to your water to enhance “dance” movement.

Disposal
Solutions may be flushed down the sink. Solids should be placed in a solid waste container.