DIFFUSION GIZMO AND CONTROLLED EXPERIMENTS

Kelvin A temperature scale based on absolute zero Absolute zero The coldest possible temperature, 0 Kelvin, that can be reached. It is the hypothetical temperature at which all molecular motion stops. controlled experiment An experiment in which only one variable is changed while keeping all other variables constant. Ex: If you were investigating the effect of temperature on the rate of diffusion, you would experiment with different temperatures, but leave the particle mass, wall size and number of particles the same in each trial. Diffusion Movement of molecules from an area of higher concentration to an area of lower concentration without the need of cellular energy (a type of passive transport) Why does diffusion occur? molecules constantly move and collide with each other causing them to spread out in a region dynamic equilibrium The end result of diffusion where there is continuous movement of particles back and forth between regions but the total number of particles in each region remains roughly constant. - a state of balance where the number of particles in a region is fairly even. ** There is some fluctuations as particles continue to move randomly. kinetic energy energy of motion What is the relationship between temperature and molecular motion? As temperature increases, molecular motion increases. As temperature decreases, molecular motion decreases. independent variable The experimental factor that is deliberately manipulated or changed by the scientist; the variable whose effect is being studied or tested. dependent variable The data collected or measured in an experiment; the factor that may respond to changes in the independent variable experimental group the group in an experiment that receives the variable being tested control group In an experiment, the group not exposed to the treatment; it contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment (the independent variable)