Nanotubes are tiny cylinders of carbon atoms that have a wide range of potential applications, including in electronics, energy storage, and medical devices. They can be formed in a variety of ways, but one of the most common methods is chemical vapor deposition (CVD).

In CVD, a hydrocarbon gas such as methane is heated to a high temperature in the presence of a catalyst, which causes the gas to break down and form carbon atoms. These atoms then condense onto a substrate, forming nanotubes.

The following video shows the process of CVD in action. The video was taken using a scanning electron microscope (SEM), which allows for the visualization of objects at very small scales.

Video: [How Nanotubes Form](https://www.youtube.com/watch?v=j2f_Q05x_0k)

The video begins with a close-up view of the substrate, which is a silicon wafer. The wafer is heated to a temperature of about 800 degrees Celsius.

Methane gas is then introduced into the chamber. The gas molecules break down and form carbon atoms, which condense onto the substrate.

The carbon atoms form into small clusters, which then grow into nanotubes. The nanotubes grow in length and width until they reach a certain size, at which point they stop growing.

The video ends with a close-up view of the nanotubes. The nanotubes are about 100 nanometers in diameter, which is about 1,000 times smaller than the width of a human hair.

Nanotubes have a wide range of potential applications, including in electronics, energy storage, and medical devices. Their unique properties make them ideal for these applications, and they are expected to play an increasingly important role in technology in the years to come.