Properties of Water: Capillary Action, High Surface Tension, Polar, Expansion During Freezing, Adhesion and Cohesion Brady Ludvik

Capillary Action The capillary action is when water is sucked into a tube because of the combination of adhesion and surface tension. The surface tension makes the water rise into the tube, while adhesion makes the water stick to the sides and cohesion brings the other molecules with it. The smaller the diameter of the tube, the higher the water will rise due to surface tension. Trees use capillary action to get water from their roots to their leaves through their thin veins.

Surface Tension Surface tension is the force of the hydrogen bonds in water along the surface of the water. The hydrogen bonds on the top of the water are linked together like the ropes of a net. Some animals can distribute their weight properly and walk in to of the hydrogen bonds without breaking them like some water insects.

Polarity Water is a polar molecule. This means that the atoms in the molecule are not evenly distributed. In water the two hydrogen atoms are on one side of the oxygen atom. The two hydrogen atoms are positive and the oxygen side is negative. This makes one side of the molecule positive and the other negative. This an attraction between water and other polar molecules. Ionic molecules dissolve in water because in ionic molecules, the atoms are negative and positive, so the negative atoms stick to the hydrogen side of water because it is positive and the negative atoms stick to the oxygen side In cells salt must me dissolved in cells to get them to work, this dissolving is due to polarity

Adhesion & Cohesion Adhesion and cohesion explain water’s ability to stick to objects. Adhesion explains water’s ability to stick to other objects than itself and cohesion explains water’s ability to stick itself. Cohesion happens because of the polarity of water. Other water molecules want to stick to it because the positive side of one molecule wants to sick to the negative end of another and vise- versa. Adhesion happens because surfaces have different charges over them. The water wants to stick to it, because it both negative and positive on different sides of itself. When you spill water across a table, it wants to stick to the top of it, because the adhesion wants to connect with the different charges along it.

Expansion When Frozen When water freezes, it expands and becomes less dense. This change in density is what makes ice float in water and other liquids. This expansion occurs because of water’s hydrogen bonds. When water is frozen, the water molecules rearrange and instead of forming in a line or grid shape, they form in a ring shape, making the take up more space and become less dense. This applies to life because if the water in your cells freeze, it will expand and break the cell. Ice Liquid Water