You may have noticed that Tuesday of this week marked the 200th Question of the Day that has appeared here on! I would like to first take a moment to thank everyone who has submitted questions, as well as all of the people who have written in with comments, suggestions and thanks for the questions in the question archive.

Answering the Question of the Day each day has is a great experience for me. I truly enjoy it, and I get to learn something new every day. As of this moment, 16,757 questions have been submitted - it is absolutely amazing to go through the new questions that arrive each day. The breadth and variety of the questions asked is incredible!

To celebrate the 200th question I would like to turn the tables and ask you, the readers of, to help me with a set of questions that I have been unable to find authoritative answers for! These questions, by the way, show up in the question box with some regularity so I would like to get them answered. Perhaps you, or a person that you know, would have access to the answers to these mysterious, impenetrable queries! Some are silly and some are serious, but in all cases I am looking for an expert who can illuminate us all. Here they are:

  1. In the U.S., household batteries come in D, C, AA and AAA sizes. What happened to A and B? And why doesn't a 9 volt battery have a letter designation?
  2. Similarly, why do letter grades in school go A, B, C, D and F. Why not E???
  3. Why does the price of gasoline have 9/10th of a cent tacked on?
  4. Why do clocks and watches use IIII instead of IV for the number 4? And why, in watch ads that you see in magazines and catalogs, do the watch hands always point to 10 and 2?
  5. What causes gray hair? When you read about gray hair in any reference source, there is always an explanation about older hair follicles ceasing their production of color pigment. That explains white hair. But gray hair is different - it has a courser texture and often curls differently from the person's normal hair, so there is more to it than the pigment. And why do the temples often get gray first? If you are a hair expert and know the real answer here, there are a lot of people who would like to know the details!
  6. How much oxygen does your basic tree produce in a day, in cubic feet or liters? What about something smaller like a dandelion or a blade of grass?
  7. What is in shaving cream that makes it so fluffy?
  8. Why do no tree-dwelling mammals have green fur, even though there are green lizards and birds?
  9. Why do your finger tips get wrinkly if you take a long bath but none of your other skin does? The answer cannot be, "because the skin absorbs water", or your entire body would get wrinkly. What is special about the finger tips?
  10. From at least 10 different readers: "Years ago in [pick a place] I saw a small kitchen device used to light gas burners on a stove. It consisted of a small wooden handle and a wire, about 16 ga. protruding from it. The end of the wire a few inches away from the handle was loosly coiled into a spring configuration about 1/2 inch or so in diameter. Inside the coil was suspended a thin wafer of some material. One placed the coil in the stream of gas from the burner and it lit the burner in a few seconds. No spark that I saw. Eventually the device lost some of its "power" and the flame took longer to light. To recharge it you simply placed it in the open flame for a minute or so and like magic it worked well again. Have you ANY idea how this works? "
  11. Why do the cans of soda in a soda machine not freeze when the machine is outside in the winter with below freezing temps?
  12. Why is it a 21 gun salute? Why not 22?
  13. Why are men's button holes are on the opposite side of women's?
  14. Why does my modem make all the funny noises when I dial up to the internet? What is the purpose of each one of the noises?
  15. Is there a reason why your iris has a color?
  16. Why are there certain sounds that can cause an unpleasant feeling? For example, fingernails on a chalkboard. Is there something genetically programmed in, and if so why?
If you have an authoritative answer to any of these, please discuss your thoughts in our Question of the Day Forum.

And thanks to everyone for making the Question of the Day such a fun and interesting experience each day!