A micrometre is 1/1000 of a metre. Things measured in micrometres are very small. Nanometres are smaller still, at 1/10000 of a metre. Red blood cells are smaller than white blood cells. When viewing a specimen under a microscope, its image appears upside down and back to front due to the way light passes through the lenses. A pipette is used to apply a drop of water to a specimen on a microscope slide.