Name: ____________________________________
Lab 1A – DIMENSIONS & UNITS
Welcome to PGEOG 130, Weather & Climate Labs. You must always show your calculations neatly
to receive credit. No calculations, no credit. All numbers must show the correct unit of measurement.
To understand the features and processes of the atmosphere, we must consider how meteorological
variables such as energy, temperature and pressure are measured. Meteorological variables can be
expressed in terms of the following fundamental dimensions:
1. Time (T)
2. Length (L)
3. Mass (M)
4. Temperature (D)
Tools needed for this lab:
 Calculator
 Protractor
Variables Important to Meteorology (show your calculations, neatly, in pencil. Show all units) Refer to
Table 1, below. Other information necessary to complete this lab is available on the web.
Multiply
by
To Get
inches
2.54
centimeters
feet
0.3048
meters
yards
0.9144
meters
miles
1.6093
kilometers
millimeters
0.039
inches
centimeters
0.39
inches
meters
3.281
feet
kilometers
0.621
miles
Length
Dimension: Length (L)
1. Convert the typical altitude of geostationary satellites (36,000 km) to miles.
km
x
miles
-----km
= miles
You’re converting km to miles and
need a conversion factor placing the
miles on top and km on bottom so
km cancel out.
Example answer:
36,000 km x 1 mile = 22,500 miles
-----1.6 km
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2.
Jets typically cruise at 37,000 feet. What is that altitude in meters?
3.
In the mercury barometer, air pressure forces mercury up a glass tube. At sea-level pressure, the
mercury is pushed to 760mm. Convert this height to inches of mercury to two decimal places.
4.
How many feet are in the following:
a.
Statute mile
= _____________________
b.
Nautical mile = _____________________
Area
Dimensions: Length * Length (L2)
5. Convert the following:
10 in2 = _________ cm2
20 m2 = _________ ft2
Volume
Dimensions: Length * Length * Length (L3)
6. What is the volume of a box, in meters, with the following dimensions:
Width: 2m
Height: 2m
Length: 2m
7.
Convert the box measurements to ft3
2
Density
Dimensions: Mass * Length-3 (ML-3)
Density equals mass divided by volume.
8. If a box has a sea-level air density of 1.24 kg m-3, how much would the air within the box weigh?
(use result from #6 above)
Velocity
Dimensions: Length * Time (LT-1)
9. If a strong west wind is blowing at 35 miles per hour, how fast is the wind moving:
In kilometers per hour?______________________
In meters per second? _______________________
Pressure
Dimensions: Length * Mass * Time (L-1MT-2)
Pressure is an important variable in meteorology and is best understood as force exerted over a unit
area. Pressure is often expressed on weather maps in millibars, that is, one-thousandth of a bar.
Standard atmospheric pressure at sea level is 1013 millibars (mb or mbar).
In the U.S. atmospheric pressure is expressed as inches of mercury (in Hg) and is defined as the
pressure exerted by a column of mercury (Hg) of 1 inch in height. Standard atmospheric pressure at sea
level is 29.92 in Hg.
10. A pressure of 30.19 in Hg would equal what pressure in millibars?
Measuring Angles
Using a protractor, measure the following acute angles:
11. Angle A ______________
12. Angle B ______________
13. Angle C ______________
A
B
C
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Scientific Notation
Is a way to conveniently write very large or very small numbers.
Ordinary Decimal Notation
300
4,720,000
0.000 000 0061
Scientific Notation
3 x 102
4.72 x 106
6.1 x 10-9
Addition Example Using Scientific Notation
Addition and subtraction problems are handled the same way.



Write the numbers to be added or subtracted in scientific notation.
Add or subtract the first part of the numbers, leaving the exponent portion unchanged.
Make sure your final answer is written in scientific notation.
(2.1 x 103) + (3.2 x 103) = 5.3 x 103
Subtraction Example Using Scientific Notation
(6.4 x 10-4) - (3.2 x 10-4) = 3.2 x 10-4
Multiplication Example Using Scientific Notation
You do not have to write numbers to be multiplied and divided so that they have the same exponents. You
can multiply the first numbers in each expression and add the exponents of 10 for multiplication problems.
(2.3 x 105) (5.0 x 10-12) =
When you multiply 2.3 and 5.3 you get 11.5. When you add the exponents you get 10 -7. At this point your
answer is:
11.5 x 10-7
You want to express your answer in scientific notation, which has only one digit to the left of the decimal
point, so the answer should be rewritten as:
1.15 x 10-6
Division Example Using Scientific Notation
In division, you subtract the exponents of 10.
(2.1 x 10-2) / (7.0 x 10-3) =
0.3 x 101 = 3
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