Every day the Earth is bombarded by material which has been formed in the solar system and is often billions of years old. Much of the material that falls from space is burned up in the atmosphere and never reaches the Earth. However, some very small particles do not get damaged as they enter Earth's atmosphere, and can be collected for further investigation. These small particles are called micrometeorites, and are less than a millimetre in diameter.
This experiment can be done as a classroom activity. The micrometeorites can be collected in a number of ways. Place a large plastic container outside and leave it for a couple of days. If it rains, collect the rainwater and filter it through filter paper. If there is no rain, wash the container and filter the water. Dry the papers and observe the residue.
This residue will be made up of lots of things, including dust from volcanoes, sand, pollution, pollen and micrometeorites.
Micrometeorites have similar compositions to meteorites - some are made from stone, but many contain iron. Those containing iron are the easiest to collect and identify, as they can be isolated from the dust using a magnet.
Place the magnet in a plastic bag (or cover with cling film) and draw it gently through the collected material. Discard the material that does not adhere to the magnet. Use a microscope to look at the material that is left. Micrometeorites are black and will often have pitted surfaces. You can find micrometeorites everywhere. For instance, try looking at the dust inside your house. Gather dust from plants and other flat surfaces on a sheet of paper. Use your magnet to separate the material, and you may find you have managed to gather some micrometeorites.