What is a centrifuge? A centrifuge is a scientific device that is used to separate fluids, gases, or liquids based on the density of the subject. The separation is acquired by spinning a container with the material at a very high speed. The resulting forces created will then cause the heavier materials to travel to the bottom of the container. In any given solution, the particles whose density is greater than that of the solvent sink, sediment, the lighter particles will float up to the top. If the difference in density is notably greater the particles will move faster and if there is no difference, they will remain steady. A much more powerful centrifugal force can be applied on top of the usual gravitational force to take advantage of even the tiny differences in densities so as to separate the various particles in a solution. When using a centrifuge machine, it is necessary to balance your samples. Balance the centrifuge machine is very important. Making sure all tubes are evenly filled with liquid similar in density. Ensuring that the masses of the tubes are within 0.1 grams of each other. Placing tubes opposite from one another inside the machine to keep the gravity in the center. When you test an odd number of tubes, it may not be possible to create balance. In these cases, fill another test tube with water and balance based on density and mass.