Properties of Water Learning Target 2a

Colorless Odorless Tasteless Water is... Colorless Odorless Tasteless

The Water Molecule: H2O Covalent bond is where electrons are shared between atoms. In water 2 Hydrogen and 1 oxygen atoms are bonded together with a covalent bonds. This is a relatively strong bond.

The “Mickey Mouse” molecule The oxygen is slightly negatively charged while the hydrogen end is slightly positive. Those positive and negative charges are attracted to each other. The “Mickey Mouse” molecule

Hydrogen Bonding Hydrogen bonding is where the positive and negative charges of the molecules are slightly attracted to each other. This is how water molecules stick together. Having positive and negative ends is called polarity. Polarity is what is responsible for all of water’s characteristics. _ + Cohesion, Adhesion, Surface Tension, capillary action, heat capacity, ability to dissolve other substances, is less dense as a solid (that’s rare).

Surface Tension Since water molecules stick together, they form a “skin” that is strong enough to resist gravity. Demo: Penny, needle or paper clip floating on water, foil boat Water skitter https://userscontent2.emaze.com/images/50533d9c-6023-4c13-a70b-74cc6b6d751a/100de6c0-9a2e-483c-93a4-bf19fab7521a.jpg Surface tension http://scienceprojectideasforkids.com/wp-content/uploads/2010/05/surface-tension-water-molecules.jpg

Cohesion When molecules of the same substance are attracted to each other In water cohesion happens because of hydrogen bonding. Demo connecting water droplets Picture http://scienceprojectideasforkids.com/wp-content/uploads/2010/05/adhesion-water-drops.jpg

Adhesion When molecules of a substance tend to stick to molecules of different substances. Rain drops Water on a paper towel Demo Microscope slides, wet paper on desk, using a rope to transfer water

Because of cohesion more water follows. Capillary Action Because of adhesion, water will move up against gravity in small tubes and pores. Because of cohesion more water follows. This is one of the major ways that plants get water from their roots. Tissues dipped in water. Demo tissue dipped in water

High Heat Capacity Water can absorb or release large amounts of heat energy without changing temperature.

Water dissolves more substances than any other known liquid. Universal Solvent Water dissolves more substances than any other known liquid. As substances are dissolved in water, small pieces of them are surrounded by water and distributed throughout the solution. solute:gets dissolved solvent: does the dissolving solution: solute and solvent evenly distributed

Universal Solvent Why is water’s ability to dissolve so many substances both good and bad?

Can you think of any way to demonstrate this? Water exists naturally as a solid, liquid, and gas at relatively normal temperatures Can you think of any way to demonstrate this? this is very rare

Liquid water is more dense than solid water Can you think of any way we could demonstrate this principal? this is extremely rare