# Shaolin monk pierces glass with a needle

The Shaolin order of monks in China is noted for its rigorous training that enables them to perform quite incredible feats of strength and endurance. They are also known for being fierce kung fu warriors, strange for Buddhist monks who are supposed to be pacifist. So how did that happen? Kallie Szczepanski provides a brief summary of the turbulent 1,500 year old history of the order that mixes legend with facts.

Andrea James links to a video where a Shaolin monk breaks a pane of glass with a needle. The act is captured with high-speed cameras and replayed in slow motion.

There is, of course, nothing magical about the act. If you throw the needle fast enough and it hits the glass head on with the pointed end, the pressure exerted is sufficient to piece the glass. It is similar to the way a bullet can penetrate glass except that the needle is so much lighter. It is the sharp point of the needle that compensates for its low mass and provides the requisite pressure.

We can do a quick calculation of the pressure exerted on the glass, assuming that the time of contact is one frame of the 28,000 frames per second of the camera. Assume that the speed with which the needle is thrown is about 100 km/hour, comparable to how fast a baseball can be thrown, and that the mass of a needle is about 25 grams. If the cross-sectional diameter of the needle point is about 1.0 mm, then the pressure on the glass is about 1010 Newtons/m2, which is huge. As a comparison, atmospheric pressure is about 105 Newton/m2.

The impressive skill of the monk lies in throwing the needle with sufficient speed and in such a way that the pointed end hits the pane almost head on. That is no mean feat.

1. says

It’s an impressive feat, but as for the pointed end hitting the pane, he wasn’t that far away from it. At that distance with some practice, I’m sure most people could have the pointed end hit each time.

Now penetrating the glass like that, that’s another story.

2. Jean says

I’d like to see a professional baseball pitcher try that. I bet it wouldn’t take too long before he was able to do it.

3. Dunc says

There’s no way that needle weighs anything like 25 grams. It’s not that much bigger than my largest embroidery needle, which apparently weighs 0.2g -- although I’m not hugely confident of the accuracy of my scale in that range. Much less than a gram, anyway.

4. rjw1 says

There’s another factor, is the glass, “prepared” in some way?

5. says

Mythbusters rather busted this a while ago. I say rather, because they did manage to do some breakage on one of their attempts. And as I look at this video, I notice two things: first, the needle did not go through the glass. It did break the glass, but the balloon was popped by the shards (and noted by the hosts). The other thing is that that is really thin glass.

To me, it’s rather like some other feats: they take advantage of physical weaknesses. Breaking boards works because they use lesser woods and hit the grain--they are playing on peoples’ perceptions. Ditto with concrete blocks, etc.