A bobby pin is basically a smaller version of a hairpin. In the United Kingdom, a bobby pin is called a Kirby Grip, or sometimes just a hair grip.
They're usually made out of thin metal or wire bent into a sort of U shape, except with the two sides closer together, and with one of the sides partly crimped. Most of them are less than 3 inches long. Some are not much more than 1 inch long.
Bobby pins hold better than hairpins in short hair, or in the smaller strands of hair used to make some of the more complicated styles. When you're giving someone a haircut or a trim you can use them to keep parts of the hair out of your way. Bobby pins used to get used a lot more than they do now, back when lots of women would actually try to sleep all night with curlers in their hair. There's still many uses for them, though. Supposedly you can even pick locks with them, but I never tried that one myself.
Be careful about using old bobby pins or really cheap ones. They're supposed to have a special coating to keep them from damaging the hair. If the coating is low quality or worn off from a lot of use, they can have rough spots that hair can get caught in and break.
Okay, I know the description up there is not the best. So I tried to make a little illustration to show what they look like just in case you haven't seen one.
_________________ _ _ _ _ _ _
/ \ / \ / \ / \ / \ / \ / \ O
\ \_/ \_/ \_/ \_/ \_/ \_/ \_/
\___________________________________________________________O
This is still not really right. The two parts of the wire should touch where it's crimped, or be a lot closer to the straight piece than I could get it. But the main shape is pretty close.
While I was working on this I got curious about where bobby pins came from. So I started searching on the Web, mostly through Google. What a wild goose chase! Pretty much everyone agrees the name of them comes from the bobbed hairstyles that were popular in the 1920s, but that's about the only thing they agree about.
Bobby pins were invented in 1920. No, 1923. No, 1926! Wait, no, we don't really know when they were invented, but they were first brought to the US in 1916. Here's some more of what I "learned":
- The bobby pin was invented in New Zealand.
(http://www.goway.com/downunder/newzealand/nz_trivia.html and
http://www.halhigdon.com/OntheRoad/newzealand/gold.html)
- It was invented in Omaha, Nebraska.
(http://www.visitomaha.com/press_room/press_room_facts.asp and
http://www.dacorn.com/)
- One guy says his grandfather had a patent on it in Japan.
(http://www.jordanschrader.com/articles/article0087.html)
- Someone named Jim Gaylord invented it.
(http://www.loti.com/gaylord.html and
http://www.car-nection.com/yann/Dbas_txt/Drm55.htm)
- It was created by someone named Luis Marcus.
(http://jerryhill.tripod.com/nqa.html)
So I guess it's true what they say about not believing everything you read on the Web.
(Thanks to shimmer for telling me these are called something else in the UK.)