1. Physics and Physical Measurement
Topic 1.1 The Realm of Physics

2. Range of Magnitudes
You will need to be able to state (express) quantities to the nearest order of magnitude
That is to say to the nearest 10x

3. Range of magnitudes of quantities in our universe (1)
Sizes
From m (subnuclear particles)
To m (extent of the visible universe)

4. Range of magnitudes of quantities in our universe (2)
Masses
From kg (electron mass)
To kg (mass of the universe)

5. Range of magnitudes of quantities in our universe (3)
Time Intervals
From s (passage of light across a nucleus)
To s (age of the universe)

6. Order of Magnitude Comparisons
You will also be required to state (express) ratios of quantities as differences of order of magnitude
Example:
the hydrogen atom has a diameter of m
the diameter of the nucleus is about m
The difference is 105 or 5 orders of magnitude

7. Estimate Everday Quantities
You should be able to estimate values of everyday quantities to one or two significant figures.
How High is a two story house in meters?
What is the diameter of the pupil of your eye?
How many times does your heart beat in an hour when relaxing?