Chemistry › States of matter › Atoms and Brownian motion

Age level:  13-15

Infobyte

Brownian motion Scottish scientist Robert Brown (1773-1858) noticed that if small particles like pollen grains are suspended in water they move in a random way. His explanation was that particles of water are hitting against the larger particles (pollen) causing them to move. This random movement of particles was called Brownian motion and it was important evidence to support the particle model of matter. This model was helpful in explaining a lot of different observations including the jerky movement of smoke particles as they rise.

Protons, electrons, charges and masses The charge possessed by a positively charged proton is equal but opposite to that of a negatively charged electron. The same cannot be said for their masses. If an electron had a mass of 1 kg a proton would have a mass of about 2000 kg.