I've been a fan of pen technology for a while now, so I was more than a little intrigued by Sharpie's recent introduction of the Liquid Pencil.
It's sort of a hybrid between pen and pencil (and I'm a fan of things that cross boundaries once thought to be immutable.) That said, it can be kind of hard to wrap one's head around Sharpie's new creation, at least until you pick one up.
Although it looks like and writes like a pen, it uses liquid graphite and erases much like a pencil.
On the plus side, it writes smoothly, doesn't break or need new lead and it is even less smudge-producing than a standard pencil and far less smear-prone than any pen.
Its erasability varies based on a bunch of factors from the type of paper to how hard you press. In general though, it erases quite well soon after writing, which tends to be the only time I would want to erase anything anyway. It's supposed to get more permanent after the first 24 hours, but will remain somewhat erasable long after that.
Engadget has soured on the liquid pencil over the fact it doesn't become truly permanent. Sharpie responded that it might have overstated things when it said in a blog post that writing from the Liquid Pencil becomes permanent like a Sharpie.
Indeed, if you are signing a contract, writing a will or what have you, I'd definitely grab a pen. But, for those who want a pencil that won't accidentally disappear over time, I think you are probably safe with the Liquid Pencil.
I would note that it doesn't write uniformly well on all surfaces. For me, I found it rather faint on the glossy program notebook from the recent Techonomy conference, but just fine on the business cards, notepads, and other paper detritus I found strewn around my desk.
All in all, I'd say the liquid pencil adds a novel alternative to the standard writing instruments without costing a fortune. The sticker price for a single liquid pencil with three little eraser refills is around two bucks.
People tend to have a lot of questions when they hear about the product, so here are a few answers. One doesn't have to use the tiny erasers that are fitted into the top of the pencil; any eraser should work. As for whether it will work with the kind of standardized tests that require a No. 2, Sharpie says that's still being tested, so you might not want to risk your S.A.T.s on it just yet.
There's a slideshow and video embedded in this post, but if you just can't get enough talk about writing implements, I went on Connecticut Public Radio on Thursday to talk about both the Liquid Pencil and the Livescribe Digital Pen for a special segment they did on the state of the pen. (Spoiler alert: It is mightier.)