Supposing I had a single strand of carbon nanotube. Would it be visible to the naked eye? Could I pick it up with my hands? Could I tie it to a paper clip and lift it?
According to this Wikipedia article, they’re really, really small - one ten-thousandth of the thickness of a human hair, or thereabouts; you’re not going to see a single, straight strand; not a chance of it. if you had a few hundred metres of the stuff coiled up in a little container, you might be able to see it (my guess is it would look like smoke).
Can’t find any specifics about the strength of a single tube (someone will no doubt be a long in a sec with that data), but if it was strong enough to use as an ordinary thread, I think you’d cut yourself trying to handle it.
No. From Mangetout’s Wikipedia article, the highest measured tensile strength of a nanotube was about 6.310[sup]10[/sup] N/m[sup]2[/sup], i.e. a nanotube with a cross-sectional area of one square metre could exert a force of 63 billion Newtons (about 14 billion pounds.) Unfortunately, these things are exceedingly small: their cross-sectional area is on the order of 10[sup]-18[/sup] square meters instead. Working through the numbers, we find a maximum force for a single nanotube on the order of 6.310[sup]-8[/sup] Newtons.
For comparison, the weight of an average grain of sand is about a thousand times greater than this. A nanotube could easily support an average cell in the human body, though, if it’s any consolation.
So what about nanotube structures similar in size to a human hair? How much weight could they hold? I don’t imagine you can just scale the numbers up based on cross-sectional area, could you? Would such a structure simply be a braid of thousands of individual nanotubes?
nanotubes are getting longer. Here is Cambridge they are made cm long, and harvested from the catalyst surface, like mowing grass, with a razor blade. While an individual nanotube is very strong, it is the strength of the composite structure it is put into that matters, and that is dependent on many factors
And these are supposed to hold up the Space Elevator?
I expect they’ll use more than one.
Anyone?
Using a estimated tensile strength of 130GPa and a width for the human hair of .001 inch, I get about 15 pounds.