I love to use this in my classroom because it is so much less distracting (and less time consuming) than students using a pencil sharpener. Besides... I teach K now, and I don't think teaching them to use a pencil sharpener would be the best use of our time! :)
Anyway, I've had lots of questions about where I found the dull pencil clipart. Well, here's a tip... go to google.com and search for "broken pencil tip". If you click on images, it should be the first one that pops up. If that doesn't work for you, than click here and see a post that uses the broken pencil within it.
Sorry, I didn't want to post the picture on my site because it is not mine to post!
Hope this helps!