Electric Grapefruit

Atoms, ions and electric grapefruit was the lesson of the day for CSI 5th Grade. My son, Kevin, is a doctoral student studying Mass Spectrometry at Texas A&M University. He is in Dr. David H. Russell's research group and is presently researching to improve the Mass Spectrometer in its ability to collect data.
After explaining a bit about ions and watching a movie of the Mass Spectrometer at work, Kevin did a couple of demonstrations to get us all thinking.

Burning a dollar bill:
After asking for a volunteer to donate a dollar bill for the experiment, he soaked the bill in some "mystery solution". Then holding it with tongs, he lit the dollar bill only to see the dollar bill flame but soon go out. The students had to figure out why this happened.



After explanation and good questioning, we talked about physical properties of atoms and molecules and looked at the periodic table of the elements.

The second demo was the can crush:
Kevin puts a small amount of water in an aluminum can and heats it until steam forms. Holding the can with tongs, he quickly turns it over and into a demo tank of cool water. The can crushes from the quick force of air pressure.





We found a website which shows this same event happening on a much larger scale with a railroad tanker. You Tube has a video, too.











Then we got some electrons moving by having the students try to light a small diode bulb with a grapefruit. The students were given alligator clips (3) diode bulb, grapefruit (cut in half), piece of zinc (2) , piece of copper (2), a penny, a nickel and a quarter. They were encouraged to try to light the bulb with the materials given. Lots of trials before we found the way to light the bulb. Journals were used to draw our experiment.





































Thanks Kevin - it was another great day of learning at CSI!