Science Bob



Science Bob was back on the show for some more science fun. You can read more about his experiments below, and try out a much this much less messy, but equally fun home-version of his exploding foam experiment. You can also find more of his experiments at www.sciencebob.com.





Fantastic Foamy Fountain

YOU WILL NEED:

  • A clean 16 ounce plastic soda bottle
  • 1/2 cup 20-volume hydrogen peroxide liquid (20-volume is a 6% solution usually available from a beauty supply storeor hair salon)
  • 1 Tablespoon (one packet) of dry yeast
  • 3 Tablespoons of warm water
  • Liquid dish washing soap
  • Food coloring
  • Small cup
  • Safety goggles



WHAT TO DO:

NOTE: Your foam will overflow from the bottle, so be sure to do this experiment on a washable surface, or place the bottle in a tray.



  1. Put on those safety goggles and carefully pour the hydrogen peroxide into the bottle. Hydrogen peroxide can irritate skin and eyes and it should only be handled by adults.
  2. Add 8 drops of your favorite food coloring into the bottle.
  3. Add about 1 tablespoon of liquid dish soap into the bottle and swish the bottle around a bit to mix it.
  4. In a separate small cup, combine the warm water and the yeast together and mix for about 30 seconds.
  5. Now the adventure starts! Pour the yeast water mixture into the bottle (a funnel helps here) and watch the foaminess begin!



HOW DOES IT WORK?

Foam is awesome! The foam you made is special because each tiny foam bubble is filled with oxygen. The yeast acted as a catalyst (a helper) to remove the oxygen from the hydrogen peroxide. Since it did this very fast, it created lots and lots of bubbles. Did you notice the bottle got warm. Your experiment created a reaction called an Exothermic Reaction - that means it not only created foam, it created heat! The foam produced is just water, soap, and oxygen so you can clean it up with a sponge and pour any extra liquid left in the bottle down the drain.

This experiment is sometimes called "Elephant's Toothpaste" because it looks like toothpaste coming out of a tube, but don't get the foam in your mouth!




Pendulum of Doom

The demonstration of the swinging pendulum demonstrated a scientific law know as the Conservation of Energy. While the swinging Pendulum of Doom had enough energy to swing back by itself, the air and the force of gravity took a small amount of that energy, making it impossible to reach it's original release point. That law of science can be of little comfort when a spiked bowling ball is racing towards your face.




Static Science

The static generator used on today's show was a Van Da Graaff generator capable of generating 500,000 volts of static electricity. The generator uses the same principle demonstrated by charging your when you walk on a carpet in the winter. The difference is that the rubber belt in the generator builds of a lot of static quickly. The pie pans in the demonstration are light enough that they can repel away from each other by their similar charge. Try charging two balloons by rubbing them in your hair and you will notice that they will push away from each other; similar to the way the pie pans pushed from each other.




The Wonders of Sulfur Hexafluoride

Ever wonder why helium makes you sound like Donald Duck? It is because helium is lighter (less dense) than air, and sound travels faster through it. The result is that the low sounds of our voice never get heard. The sulfur hexafluoride creates the opposite effect - sound travels slower through it and the low timbre of our voice prevails making on sound more like Barry White. Interestingly, sulfur hexafluoride does not allow electricity to pass through it and so it is often used in electrical transformers to keep wires from sparking.