Quiz #471 Results
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Answers to Quiz #471- March 29, 2015
1. What is the name of this device?
2. How do you use it to measure the height of a building?
Give three DIFFERENT ways.
TinEye Alert
You can find this photo on,
but the quiz will be a lot more fun if you solve the puzzle on your own.
1.  A water barometer, weather barometer, storm barometer.
2.  See below.

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Weather Ball Barometer
The weather ball barometer is based on a simple design by
Goethe. The glass globe is attached to a sturdy base with a
funnel tube on one side. The ball is filled with colored
distilled water. Once filled the air trapped inside the ball is
no longer subject to variations in atmospheric pressure. The
liquid in the indicator tube, however, remains open to the
atmosphere and is directly affected by atmospheric
pressure. When atmospheric pressure rises, the liquid in the
indicator tube is pushed down and an improvement in the
1. Measure the barometric pressure at the top and
at the bottom

Measure the barometric pressure (in mm of mercury)
at the base of the building. Take the barometer to the
roof of the building, and measure the pressure again.
The difference tells you the weight of a column of air
the same height as the building. Multiply the pressure
difference (in mm of mercury) by the density of
mercury compared to the density of air around the
building. This gives you the height of the building (in
mm). Use standard tables to convert to the required
unit of measurement.

2. Drop the barometer and time how long it takes
to fall

Take the barometer to the roof of the building. Walk
to the edge. Drop the barometer over the edge and
time how long it takes to hit the ground. You may
either watch the barometer fall, or listen for it hitting
the ground, depending on the height of the building
and the accuracy required. Don't forget to correct for
the speed of sound if listening for the crunch. Use the
fact that height is gravity times the square of the time,
divided by two to calculate height from the (known)
gravity and the (measured) time.

3. Use the barometer as a measuring stick

Place the barometer upright against the wall. Mark the
top of the barometer. Label the mark '1'. Move the
barometer vertically so that the bottom of the
barometer is at the mark. Mark the top of the
barometer, labelling this mark '2'. Continue like this
until you reach the top of the building. Multiply the
number on the last mark by the height of the
barometer. This will be accurate to within one
barometer height. For greater accuracy, add one-half
the height of the barometer to account for the portion
above the last mark.

Note: For tall buildings, some extra equipment may be
required to assist in climbing the wall.

4. Use the barometer as a pendulum

Buy a rope long enough to reach the top of the
building. Tie the barometer to one end and go up on
the roof. Lower the barometer until it is exactly one
inch above the ground. Holding the top of the rope at
the top of the building, swing the barometer, and
measure the period of the pendulum. From this you
can calculate the length of the rope. Add one inch and
you have the height of the building.

5. Measure the shadow of the barometer and the

On a sunny day, measure the length of the shadow
cast by the barometer, and the length of the shadow
cast by the building. Multiply this ratio by the height of
the barometer to get the height of the building.

6. Compare the barometer height to the building

Hold the barometer one foot in front of yourself and
find a position where the building appears to be the
same size as the barometer. Now measure the distance
to the building (in feet) and multiply by the height of
the barometer.

7. Trade the barometer for a long measuring tape

Go to a local shop and trade the barometer for the
longest measuring tape they have. Take the tape onto
the roof of the building. Holding one end, drop the
other end over the edge of the building. Raise the
measuring tape until the far end is just touching, not
resting on, the ground. Read the height of the building
from the measuring tape.

Note: For particularly tall buildings, this may require a
particularly good hardware store.

8. Offer the barometer to the superintendent

Find the superintendent of the building. Offer him a
deluxe display barometer if he will tell you the height
of the building. If the superintendent is not available,
or doesn't like barometers, try other parties such as
the local survey officer, the original architect, or a
member of the construction crew.
weather can be anticipated. When air pressure falls, the greater pressure inside the ball
causes the liquid in the indicator tube to rise, indicating that a deterioration in weather
can be expected.
How to Measure the Height of a Building with a Barometer
Comments from Our Readers
There is something to be said for an oldie and a goodie, aside from the fact that I
always love an oldie, one might say that they're always reliable and a solid constant.
Don't know where we'd be without them sometimes.

As Mark Twain wrote in relation to April 1st, "This is the day upon which we are
reminded of what we are on the other three hundred and sixty-four".  :)  Happy belated
April Fool's Day to you as well, Colleen and a Happy Easter too!'
Cindy Costigan
I liked the one about throwing the barometer off the top of the building and
calculating its speed.
Tynan Peterson
Niels Bohr is reputed to have also  suggested throwing a barometer off the top of
the building and timing its fall and swinging a barometer on a string as a pendulum
first at street level then at the top of the building.
Margaret Paxton
It would look great on the shelf sitting next to the Galileo Thermometer.
Carol Farrant
Carry device to top of building. Using a laser interferometer, measure its
acceleration when dropped a few centimeters (or inches), and call that A1. Catch it
carefully and take it back to the ground. Repeat the measurement, A2. Since A2 is
closer to the center of the earth, it will be slightly greater than A1. The difference is
nearly linearly related to the building's height, and can be calculated.
Collier Smith
Trade the device to the building janitor/superintendent in exchange for the
information about the height of the building. [This assumes he/she is intrigued
enough by the device to give you the information.]
Tony Knapp
Another quiz in which google gave me the answer by just starting to type. All I did
was trying to google "how to measure the height of a building" and the suggestions
came up with "with a barometer". Thanks Google.
Ida Sanchez
There is a company that sells this item with Galileo's Thermometer on a nice
wooden base - a very stylish way to watch the weather!
Unsigned Entry
See the cute story at
John Thatcher
Figuring out what the device was was simple; it probably would have been
even without the markings on the bulb. Thinking up unusual ways to use the
device to measure building height was kind of fun, though.
Roger Lipsett
(My favorite) Take a photo of the building and the barometer together. Measure the
height of the barometer in real life and in the picture. Use that ratio to convert the
height of the building in the picture to get the actual height.
Dawn Carlile
Happy April's Fool Day!