Define each of these in your own words: Surface tension 2) Heat capacity It is midnight, you are standing with your feet in the water on the beach facing the waves. Describe how the wind will be blowing?

Water properties Water Quality/chemistry Water-the universal solvent Dissolved Oxygen Turbidity Acid/base Nitrogen cycle (ammonia, nitrite, nitrate) Phosphates & Eutrophication Hard and Soft water Conductivity of water Alkalinity Water Physical properties Water pressure & Pascal's principle Scuba diving & dissolved gasses at pressure Surface Tension Heat capacity Buoyancy & Archimedes principle Density & the water density anomaly Bernoulli’s principle

Fluid = gases & liquids Fluid = A fluid is a substance that easily and continually deforms (flows) under an applied force Pressure of a fluid (gas and liquid) is the sum of all collisions of the particles on the

1) Pascal’s Principle Pressure applied to fluid in a closed container is equally transmitted to all parts of the fluid and the container. Think toothpaste…

1) Applications of Pascal’s Principle… We use Pascal's principle a lot in things that need power… car jacks, car brakes, tractors & construction machines Under water, the weight/pressure of the water is a “squeeze” not a downward weight

Summary: There are several problems associated with scuba 1) Pressure is crushing even a small distance under the water (pascal’s principle) 2) Breathing air that is under pressure makes you a soda can! a) blood dissolves more air with pressure b) coming up fast can cause bubbles in your veins = painful… and deadly

2) Surface tension This bug will sink if it breaks the “surface tension This bug & paperclip CANNOT do this on oil, alcohol or any other fluid!!! This bug would not be able to do this in salt water either since the waters are all stuck to salt instead of each other.

3) Surface tension is because of Hydrogen bonding

3) Water has “surface tension” due to water molecules sticking together (hydrogen bonding)

3) Summary Why can a bug that should sink, stay on top of the water? a) weak hydrogen bonds between water allow him to stand on the water b) the bug is less dense than water c) the covalent bonds are very strong d) water is very dense.

4) Water has an extremely high heat capacity If you had 1gram Aluminum, 1gram of copper and 1gram of water and give each 1cal of heat. Aluminum will change about 5degrees Copper will change more than 10 degrees Water will only change 1degree

4) Summary : Heat capacity of water takes in heat slowly, it does not change temperature fast has more heat than most things – at the same temp releases heat slowly too, so it can provide a constant source of heat at night

4) Remember “convection” Heat makes things expand and rise Cold makes things contract and sink If one place it hotter,… what will happen to the air above it and thus the wind?

4) The “Sea breeze”… that all coastal people know about.

question It is a sunny hot day around noon, you are standing with your feet in the water on the beach at Port Aransas facing the waves. The wind will most likely be blowing: North In your face On your back No way to know

5) Buoyancy Tankers are made of steel and weigh as much of 585,000tons!!! They are 1500ft long, 225 ft wide… and extend >50ft into the water! How do they float?

5) The Buoyant Force is why… --- Some things float and sink & why even things that sink feel lighter in water.

5) Archimedes principle

5)Archimedes’ Principle Buoyant force = weight of fluid displaced

5) Archimedes Example

5) Archimedes principle: example

5) Archimedes Example 2 lb fish, displacing 2.5lbs of water 2 lb fish,

Review “Cartesian diver” Combo Pascal & Archimedes princ. Force on side equally transmitted up the tip Bubble is no “displacing” less water… less than it’s weight

Test question The force that holds floating objects up is the buoyant force, explained by…. a. Pascal’s principle b. Bernoulli's principle c. Archimedes's principle d. Density’s principle.

Test question The “Cartesian diver” (dropper in a bottle) is an example of…. a. Pascal’s principle b. Bernoulli's principle c. Archimedes's principle d. both a and c.

Or: A ball weighs 10 lbs, it will float if the same size ball of water weighs… a. Less than 10 lbs b. more than 10 lbs c. 10 lbs is not that heavy , so it will always float d. 10 lbs is pretty heavy, so it will always sink

6) Water’s density anomaly

6) MOST things are denser as solids Most things continue to shrink as they “freeze” so the solid form is denser than the liquid form H2O is the only compound we know of that expands when it freezes. Solid water takes up more space than the same mass of liquid water… so due to Archimedes principle… it floats.

Summary Water is the only substance in your life whose solid form is LESS dense than it’s liquid form This has huge impacts on the natural world!!!

7) Bernoulli’s Principle The pressure of a fluid (gas or liquid) decreases as the fluid’s velocity increases.

7) Bernoulli’s Principle The pressure of a fluid (gas or liquid) decreases as the fluid’s velocity increases.

7) Does Bernoulli's principle apply to water too? Of course, it applies to all fluids (gas & liquids) Sharks especially use it to stay up… they normally sink if they stop moving.

7) Bernoulli’ principle demo Beach ball and leaf blower https://vimeo.com/13647441 It’s harder to demonstrate with water…..

Reminder: know them by name We have talked about three principles that describe some physical properties of water Can you match them with their correct property: Bernoulli Archimedes Pascal Buoyancy force is weight of displaced water Fast flowing water has less pressure than slow water Pressure is evenly distributed in all directions

Water pressure & Pascal's principle Surface Tension Heat capacity Buoyancy & Archimedes principle Density & the water density anomaly Bernoulli’s principle