demonstrate knowledge and understanding that nanoparticles are structures that are 1-100 nm in size and contain a few hundred atoms;
demonstrate knowledge and understanding of surface area to volume relationships and that, as the side of a cube decreases by a factor of 10, the surface area to volume ratio increases by a factor of 10;
demonstrate knowledge and understanding that nanoparticles have properties different from those for the same material in bulk, due to their high surface area to volume ratio;
evaluate the benefits of nanoparticles in sun creams, including better skin coverage and more effective protection from the Sun's ultraviolet rays, and the risks, such as potential cell damage in the body and harmful effects on the environment;