1. Properties of Water
Learning Target 2a

2. Colorless Odorless Tasteless
Water is...
Colorless
Odorless
Tasteless

3. 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.

4. 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

5. 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).

6. 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
Surface tension

7. 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

8. 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

9. 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

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

11. 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

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

13. 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

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