1. Introduction to Pressure

2. Temperature Conversions
We use three scales to measure temperature: Fahrenheit (F), Celsius (C) and Kelvin (K).
The size of each degree is the same for the Celsius and Kelvin scales.
Example: there are 100 units between freezing and boiling points on both scales
Fahrenheit units are smaller than Celsius and Kelvin units
Example: there are 180 units between freezing and boiling points on the Fahrenheit scale.
0 is at a different point on all three scales.

3. Converting between the scales:
Fahrenheit to Celsius:
(⁰F – 32) x 5/9
Celsius to Fahrenheit:
9/5(⁰C) + 32
Celsius to Kelvin:
⁰C + 273
Kelvin to Celsius:
⁰K – 273
Overall equation:
K= 5/9(⁰F-32) + 273

4. Examples
70⁰F to C
35⁰C to F
23⁰C to K
310⁰K to C
45⁰F to K

5. Brain Break: Stair Stepper
Climb 1: Serpentine
Climb 2: Foot Cross Climb
Climb 3: Squat Climb

6. What is Pressure?
Pressure: the force per unit of area on a surface. The random motion of particles pushing against the inside surface of a container causes pressure.
The pressure depends on the volume, temperature and the number of particles present.
Measured in Newton’s, Pascals (or Kilopascals),
pounds per square inch (psi), Millimeters of
Mercury (mmHg), atmospheres (atm).

7. Atmospheric Pressure
The force exerted on a surface by the air above it as gravity pulls it towards Earth.
Measured with a barometer
A column of mercury in a glass tube that will rise or fall as the weight of the atmosphere changes.
The unit is 1 atmosphere (atm)
It is the average pressure at sea level when the temperature is 15 degrees Celsius (59 degrees Fahrenheit)

8. Atmospheric Pressure at Altitude
Atmospheric pressure drops as the altitude increases.
This is because there is less air above that point in space to press down on the object.
The atmospheric pressure on Denali in Alaska (the highest point in the US) is about half of that in Honolulu, Hawaii.
Airlines also create artificial pressure so that passengers don’t suffer altitude sickness as they fly.

9. Predicting Weather
We can also use atmospheric pressure to predict the weather.
Low pressure creates clouds, wind and precipitation.
High pressure systems usually lead to nice weather.