All particles of matter (atoms, molecules, even very small drops or granules) possess kinetic energy, that is, they are moving. In a solid, particles vibrate without being displaced much. In a liquid, the particles are moving faster (they have more kinetic energy) so that they bounce off of and move past each other. In a gas, the particles have so much kinetic energy that they bounce farther and tend to be more dispersed. Although each particle may have different kinetic energy, the average kinetic energy of all the particles in a given sample of matter is referred to as the temperature. Higher temperature means higher average kinetic energy of particles. At 'absolute zero' (0 K, or -273.15 °C) there is no kinetic energy and particles are not moving at all, but this state is presently impossible for us to achieve. It is important to note that larger particles will be moving slower at a given temperature because the same amount of kinetic energy will move a larger mass at a slower speed. The movement of individual particles is essentially random. For example, in a glass of 'still' water, water molecules bounce off each other and jostle about. If we followed one specific water molecule, it would not go in any particular direction. Rather, it would go one way, bounce off another water molecule, and go a different way, bounce again... Even so, that water molecule is likely to eventually visit most all of the glass if we watch long enough. We cannot easily follow the movement of a water molecule (they are invisible, even under a microscope), but small droplets or particles in water may be seen moving about as they are jostled by water molecules and each other. The continuous random movement of particles in water is known as Brownian movement (after the first person to describe it, Robert Brown). Prepare a wet mount of a small drop of milk with a generous drop of water and examine under high power (don't forget to start with the scanner lens and work your way through the low power lens first). Focus on one tiny droplet of fat suspended in the water (they look like tiny specks) and note what it is doing. Repeat for several such droplets. These droplets may be moving together across the field of view due to water currents, but that is not what you are looking for. The droplets are tiny. So if you are finding it difficult to find them, find the edge of the cover slip, bring that into focus, and work your way from there. What are the observations, and why are the small particles that you see more active?