1. Properties of Water (Part 1)

2. Water
The most important molecule to living things.
Why?

3. - Properties of Water + + H2O 2 Hydrogen atoms and 1 Oxygen atom H H O
What is the chemical formula for water?
H2O
2 Hydrogen atoms and 1 Oxygen atom H H + + - O

4. Water is a polar molecule
This results in a water molecule with a negative end and a positive end.

5. Polarity = Strong bonds
The negative end and positive end
of the water molecules attract like
a magnet.
The bonds between water molecules are SO strong that they are…
Hard to break apart
Stick together easily

6. Because water is polar it has these properties:
Adhesion - water molecules stick to other molecules
Cohesion- water molecules stick together

7. Because water is polar it has these properties:
Capillary action - allows water to move UP and through materials (both adhesive and cohesive forces working together).

8. Because water is polar it has these properties:
Surface tension - inward pull of surface water molecules creating a smooth sheet

9. Properties of Water (Part 2)

10. Universal Solvent – water is known as this because it can dissolve any polar substance.

11. Specific Heat
Specific Heat - The amount of heat needed to increase the temperature by 1 degree Celsius.
Water has a HIGH Specific Heat!
It takes A LOT OF HEAT to raise the temperature of water.

12. Specific Heat Example
It’s a hot day! The sidewalk is hot, the sandy beach is hot. So, you decide to go to the beach. When you jump in the ocean, the water is surprisingly cool!
Why??? Because it takes more heat to warm the water then the sidewalk, beach and air!

13. Water’s Specific Heat Why does water have a HIGH specific heat?
It’s POLAR!!!
The molecules are SO attracted to each other that it takes A LOT of heat to break the molecules apart.

14. Density of Water Water has a Density of 1.0 g/ml
If an object SINKS in water, then it is MORE dense than water and has a density greater than 1.0 g/ml
If an object FLOATS in water, then it is LESS dense than water and has a density less than 1.0 g/ml

15. Sink or Float?
Decide if the objects will SINK OR FLOAT given their density.

16. Why does ICE float? Ice is LESS DENSE than water.
When water freezes and becomes a solid, the molecules are spread out, more than when water is a liquid. This makes the volume of the ice increase.
This makes ice less dense than the water, and it will float!

17. Density Column Demonstration
If we pour water, vegetable oil, and corn syrup into a beaker, what do you predict will happen?
Now we will add different objects and observe where they sink or float in the density column.
Complete the diagram in your notes based on the results of the experiment.

18. Buoyancy

19. Why does a very heavy,
very dense, very large boat
float in water? …
because of Buoyancy!
Buoyant Force – The upward force exerted in water and other fluids.

20. Buoyancy vs. Gravity Gravity pushes down Buoyancy pushes up
Buoyancy acts in the opposite direction of gravity.
Gravity pushes down
Buoyancy pushes up

21. Buoyancy = Water Displacement
The volume of water displaced by the object equals the object’s buoyancy.
 How much water is displaced by the egg?
That is the egg’s buoyancy!

22. So, why does a boat float? It is not less dense than water…
It does not weigh less than water…
The shape of the hull (bottom of the boat) displaces a volume of water EQUAL to the submerged part of the boat.