Lecture panel 1

Question 1

Used by Egyptians 5000 years ago

Answer 1

Stream gauges

Question 2

Who used rainfall gauges 3200 BP?

Answer 2

India and China

Question 3

Why first correctly described the hydrologic cycle and when?

Answer 3

Greek philosophers 2200 BP

Question 4

How did da Vinci measure streamflow?

Answer 4

put inflated bladder in stream and followed it, walking while measuring distance and time

Question 5

Angle between H on water molecule

Answer 5

105 (or 104.5)

Question 6

What properties of water does its shape create?

Answer 6

• large latent and specific heat capacity
• cohesive nature
• large surface tension
• “universal solvent”

Question 7

specific weight - where is it max for water?

Answer 7

weight per unit volume - max at ~4C

Question 8

What is dynamic viscosity?

Answer 8

tangential force per unit area required to move one horizontal plane wrt another plane at unit velocity

Question 9

What temp does water have max density at?

Answer 9

4C

Question 10

What causes freeze-thaw processes?

Answer 10

expansion of water in solid state

Question 11

What is the difference between freezing fresh water vs salt water?

Answer 11

salt water freezes at its maximum density, which allows sea ice to occur without overturning

Question 12

What would the freezing and melting points of water be without H-bonding?

Answer 12

freeze -100C

melt -91C

Question 13

What is unique about Earth in the solar system (regarding water)

Answer 13

• Large reservoirs of liquid water

- situated where water can exist in all three phases (conditions close to triple point of water)

Question 14

How does pressure affect ice melting point?

Answer 14

pressure reduces ice melting point

Question 15

What is specific heat?

Answer 15

amount of energy required to raise the temperature of a substance by a single degree

Question 16

What is water’s specific heat, and why is it high?

What affects does this have?

Answer 16

4. 2 KJ/kg/K
   - it is high because if H bonding
   - makes water a good habitat for aquatic species, allows warm blooded species to regulate their temperature
   - moderates climate

Question 17

What does water’s high heat capacity mean for heat transportation by oceans?

Answer 17

• oceans responsible for 1/4 to 1/3 of all heat transported to the poles
• greatly moderate climate

Question 18

What is the heat capacity of oceans compared to the atmosphere?

Answer 18

120x

Question 19

latent heat of vapourization

Answer 19

quantity of heat absorbed (released) when unit mass of a substance vapourizes (condenses)

Question 20

latent heat of fusion

Answer 20

quantity of heat absorbed (released) when a unit mass of substance melts (freezes)

Question 21

What is a consequence of water’s latent heat as it cools in soil?

Answer 21

Soil temperature around water will increase, as calories are released by the phase transition from liquid to solid.

Question 22

What does surface tension allow?

Answer 22

• allows water to adhere to a wet surface

- allows for capillarity (important for soil water movement)

Question 23

what do water’s solvent properties mean for earth and life processes?

Answer 23

• -important for biogeochemical cycling, chemical erosion, and life processes
• in rivers, dissolved load is a significant portion of all material transported by rivers to oceans (could exceed suspended load)

Question 24

What percent of sediment load in Lake Ontario is dissolved?

Answer 24

92%

Question 25

What is the most important greenhouse gas? What would surface temp be without it?

Answer 25

Water vapour - surface temp would be -18

Question 26

What property must a water column have for freezing?

Answer 26

isothermal

Question 27

What shape are water droplets?

Answer 27

Small are spheres, large are donuts due to surface tension

Question 28

Water helps Earth absorb a lot of energy from the sun in the range

Answer 28

infrared - emission spectra from earth significantly altered from that of black body