155 reputation
bio website cobaltduck.info
location Milford, OH
age 44
visits member for 4 years, 5 months
seen Nov 24 at 20:10

A former math teacher for 10 years, converted to Software Engineering just a few years ago. Enjoy woodworking, kayaking, hiking, and geocaching.


comment Does gravity exist in a vacuum?
When I was in high school, a teacher put a rubber ball and a feather into a clear plastic tube. He tilted the tube back and forth and we saw the ball fall rapidly while the feather drifted down slowly. He then sealed the ends of the tube and used a pump to remove (almost) all of the air inside. He tilted the tube back and forth again and the ball and feather fell side by side at the same rate. Ok, so the tube was not a 100% complete vacuum, and the gravity acting on the ball and feather came from the earth which was not in the tube. But sometimes these simple little demos go a long way.
comment Why earth looks always flat when it is round
I am a microbe. I live on the surface of a bowling ball. I am convinced it is perfectly flat.
comment Can bad guys really hide “dirty bomb” material via bananas?
@dmckee Agree! It happens too often that I try to to enjoy some movie or TV show, and some event has me mumbling "Oh, bull$&!+." and ruins my 'suspension of disbelief.' I suspected it was unlikely, but this one left me scratcing my head. I guess I hadn't made the mental leap between this quote from the link in my question: "the radioactivity from a truckload of bananas is capable of causing a false alarm when passed through ... " and the much stronger statement "if said truck contained a Goiania-like device, the authorities would just assume it was due to the bananas and wave it through."
comment Can bad guys really hide “dirty bomb” material via bananas?
@dj_mummy While that was the story line of the episode, I'd like to hear a more general explanation (positive or negative) of whether bananas can disguise any material that could be used to build a "dirty nuke."
comment Is there anything special about the Sun's photosphere in terms of density?
@John: The wikipedia article does address a part of my question, thank you. And I hadn't known about the Shock Front previously, which is very interesting. However, it does not get to my specific point, whether anything special goes on at the photosphere.
comment Thought experiment that seems to involve something growing at twice the speed of light. Is anything wrong?
@David: Duly noted. Thanks for enlightening me.