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Different substances and their properties



The table shows some of the units used to measure length. As you go down the table, each unit is 1,000 times smaller than the one above it.

Units used to measure length

Unit nameUnit symbolMeaning
gigametreGmone billion metres
megametreMmone million metres
kilometrekmone thousand metres
metremone metre
millimetremmone thousandth of a metre
micrometreµmone millionth of a metre
nanometrenmone billionth of a metre
atoms arranged in circular patterns

Nanotubes like this could be used to make tiny mechanical devices, molecular computers or extremely strong materials

Nanoparticles range in size from about 100 nm down to about 1 nm. They are typically the size of small molecules, and far too small to see with a microscope.

Working with nanoparticles is called nanotechnology.

Uses of nanoparticles

Nanoparticles have a very large surface area compared with their volume. So they are often able to react very quickly. This makes them useful as catalysts to speed up reactions. For example, they can be used in self-cleaning ovens and windows.

Nanoparticles also have different properties to the same substance in normal-sized pieces. For example, titanium dioxide is a white solid used in house paint and certain sweet-coated chocolates. Titanium dioxide nanoparticles are so small they do not reflect visible light, so cannot be seen. They are used in sunblock creams to block harmful ultraviolet light without appearing white on the skin.

Nanoscience may lead to the development of:

  • new catalysts
  • new coatings
  • new computers
  • stronger and lighter building materials
  • sensors that detect individual substances in tiny amounts.

Back to Atomic structure and bonding index

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