Station 1
Measurement System
Rube Goldberg Machine Design Contest Teacher Training Program
January 29, 2005
Introduction
There are so many things around us that we can measure, and it is no surprise that there are
already several established measurement systems. At this station, you will be familiarizing
yourself with the metric system in addition to the English system, and identifying several
mystery items and their properties.
Background
Metric System
The United States is the only country in the world that doesn’t actively use the metric system. In
order to communicate with engineers from across the world (including the US), you must learn
to be comfortable with both the English measuring system and the metric measuring system.
The metric system is very simple; everything is base 10. For example, 1 meter = 10 decimeters =
100 centimeters = 1000 millimeters, 1 kilometer = 1000 meters, 1 liter = 1000 milliliters, etc. So
all you really have to learn is the prefix, and they are listed as follows:
Prefix
pico
nano
micro
milli
centi
deci
no prefix
deka
hecto
kilo
mega
giga
tera
Symbol Decimal Equivalent Exponential Equivalent
p
0.000000000001
10-12
n
0.000000001
10-9
0.000001
10-6
m
0.001
10-3
c
0.01
10-2
d
0.1
10-1
1
100
da
10
101
h
100
102
k
1000
103
M
1000000
106
G
1000000000
109
T
1000000000000
1012
Simply attach the prefix to the common units of measure. For example, when describing 1/1000th
of a second you can say “ 1 millisecond” or “1ms.” Now let’s try out some practice problems.
Convert the following:
19.6 cm = _______ m
0.5 sec = _______ ms
16.4 L = _________ mL
The measurements and calculations that you will be making when designing and building a Rube
Goldberg machine will often require you to express large or small numbers more compactly. The
metric prefixes will thus come in very handy, so start getting used to it now!
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Common Units of Measure
For almost every measurement, there is a common measurement unit. Here we will focus on the
common units of measure for time, distance, velocity, acceleration, area, volume, capacity, mass,
force, and energy. The common names and units for both systems are presented below.
Quantity
Time
Distance
Velocity
Acceleration
Area
Volume
Capacity
Mass
Force
Energy
English
second (sec)
foot (ft)
feet per second (ft/s)
feet per second squared (ft/s2)
feet squared (ft2)
feet cubed (ft3)
fluid ounce (fl. oz.)
pound (lb)
dyne (dyn)
calorie (cal)
Metric
second (sec)
meter (m)
meters per second (m/s)
meters per second squared (m/s2)
meters squared (m2)
meters cubed (m3)
liter (L)
kilogram (kg)
Newton (N)
Joule (J)
Remember that metric prefixes only apply to the metric system.
To convert from English units to metric units, multiply by the value in the “multiply by” column.
To convert the other way, divide by the number in the “multiply by” column.
From English
inch
ft
fl. oz.
lb
To Metric
centimeter
m
L
kg
Multiply by
2.54
0.3048
0.0295735
0.4535924
Try the following examples:
8 fl oz = _________ L
1.54 m = __________ ft
2.2 lb = __________ kg
Experiment Time!
Purpose
As a scientist or engineering, you will not always have accurate measurement devices available
to you. It’s critical that you make as best an approximation as possible regarding the object’s
dimensions or qualities. So at this station, you will gain an intuitive feel for dimensions and
qualities of physical objects.
First you will make several measurements using calibrated standards in both English and metric
units. Next you will be presented with several objects whose qualities need to be approximated
because you don’t have the handy-dandy calibration standards to compare against. Finally you
will check how close your approximations are to the actual measured values.
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Procedure
Section A
1. Choose an object and a measuring device.
2. Make a guess in both English and metric units as to the dimensions of the object you’re
about to measure and record in the appropriate columns.
3. Measure the dimensions of the object and record in the appropriate columns.
4. Compare your guess with the actual measurement. How similar were they?
5. Repeat the above steps with the other objects. Try to guess as close to actual dimensions.
Guess Length
Actual Length
Textbook 1
Difference Guess Thickness
Actual Thickness
Difference
English
Metric
Guess Length
Actual Length
Textbook 2
Difference
Guess Width
Actual Width
Difference
Actual Length
Mousetrap
Difference
Guess Width
Actual Width
Difference
Experiment Table
Difference
Guess Height
Actual Height
Difference
English
Metric
Guess Length
English
Metric
Guess Length
Actual Length
English
Metric
Section B
1. Pick up a mass in the calibrated mass set, starting with the smallest value. Get a feel for
how heavy it is (its weight). Increment to the next smallest mass until you have gained an
intuitive feel for all the masses.
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2. Pick up some other masses on the table and get a sense of how heavy they are. Note their
actual masses.
3. Choose a “mystery” object on the table and guess its mass without lifting it. Record
English and metric guesses in the appropriate columns.
4. Pick up the “mystery” object you chose and guess its mass again. Record in the table.
5. Write down the actual mass of the object given to you by the Station Leader. Calculate
the differences.
6. Repeat steps 3-5 for the other objects, trying to be more accurate with your guesses.
Guess Mass (1)
Mystery Object 1
Guess Mass (2)
Actual Mass
Difference
Guess Mass (1)
Mystery Object 2
Guess Mass (2)
Actual Mass
Difference
Guess Mass (1)
Mystery Object 3
Guess Mass (2)
Actual Mass
Difference
Guess Mass (1)
Mystery Object 4
Guess Mass (2)
Actual Mass
Difference
English
Metric
English
Metric
English
Metric
English
Metric
If there is time, you can request more objects for practice. Please ask your Station Leader.
Congratulations! Now you have an intuitive feel for some common weights and measures in both
the English and metric system!
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