1. Flow rate depends on:
Potential difference
Area (size of “pipe”)
Permeability (or “roughness”)

2. Water flows from high potential to low potential
Same high potential
Lower potential
A high flow rate generates lots of power

3. The opposite of Conductance is
In a water pipe: “Conductance” is proportional to AREA x PERMEABILITY
Area (size of “pipe”)
Permeability (if the water must flow around sand or gravel in the pipe)
The opposite of Conductance is
“RESISTANCE”

4. The opposite of Conductance is
In an electric wire or light bulb: “Conductance” is proportional to AREA x CONDUCTIVIY
Area (size of “wire” or “filament”)
Conductivity (the current must flow around atoms in the wire)
The opposite of Conductance is
“RESISTANCE”

5. Imagine water flowing in a “loop” or “circuit”

6. Imagine water flowing in a “loop” or “circuit”

7. Imagine water flowing in a “loop” or “circuit”

8. Imagine water flowing in a “loop” or “circuit”

9. Units:
“Fluid potential” is measured in the same units as “pressure”
The SI unit of pressure is the Pascal or “Pa”
Pascals are tiny so we often use kilopascals or “kPa”

10. Units:
A useful unit for work and energy is the joule.
One joule is about ¼ calorie.
One joule is also the energy needed to move one liter of water through a potential difference of one kPa.

11. Units:
Power is “energy per unit time”
Power is measured in watts
1 watt = 1 joule per second

12. Units:
1 watt = 1 joule per second
Lighting a 40 watt bulb for 10 seconds consumes 400 joules of energy
1 kWhr = (1 kW)(3600 s) = 3.6 million joules

13. Electrical Units:
The stuff that flows is called CHARGE
The unit of charge is the COULOMB
The flow of charge is called CURRENT
The unit of current is the AMP
1 𝑎𝑚𝑝= 1 𝑐𝑜𝑢𝑙𝑜𝑚𝑏 𝑠𝑒𝑐𝑜𝑛𝑑

14. Electrical Units:
The unit of potential is the VOLT
A potential difference is called VOLTAGE
1 𝑣𝑜𝑙𝑡= 1 𝑗𝑜𝑢𝑙𝑒 𝑐𝑜𝑢𝑙𝑜𝑚𝑏

15. Electrical Units:
The unit of energy is the JOULE
Energy is determined by
The amount of charge that moves
The change in potential of each charge
𝐸𝑛𝑒𝑟𝑔𝑦 𝑖𝑛 𝑗𝑜𝑢𝑙𝑒𝑠=(𝑐ℎ𝑎𝑟𝑔𝑒)(𝑣𝑜𝑙𝑡𝑎𝑔𝑒)

16. Electrical Units:
The unit of power is the WATT
Power is determined by
The rate of motion of charge (CURRENT)
The change in potential of each charge
𝑃𝑜𝑤𝑒𝑟=(𝑐𝑢𝑟𝑟𝑒𝑛𝑡)(𝑣𝑜𝑙𝑡𝑎𝑔𝑒)
𝑤𝑎𝑡𝑡𝑠=(𝑎𝑚𝑝𝑠)(𝑗𝑜𝑢𝑙𝑒𝑠)