We ended with crystalline solids on Wed. Amorphous solids were discussed as to structure and compared with crystalline solids. Molecular models were used to demonstrate that the molecules in a solid do not move freely, giving the solid a definite shape. The molecular arrangement in a liquid was demonstrated, showing that the molecules could move about more freely, they had the abitlity to flow. Liquids were shown not to have a definite shape, but would take the shape of the container. Liquids did have mass and volume, which could be determined by using a balance and a graduated cylinder. The characteristic of surface tension was explained and demonstrated with a clip floating on water, with food coloring placed in water and suddenly separating when a drop of soap was inserted, lowering the surface tension. A paper boat placed in a dish of water was caused to move by placing a Q-tip of soap behind it. The air pressure and surface tension was demonstrated using a bottle filled with water, a cardboard card covering the opening and then turned upside down and your hand removed. The card remained attached, due to surface tension and air pressure.