Pi Day Quiz 2019

Edison Tech Center Pi Day Quiz 2019

This year the Edison Tech Center is working on a mapping machine to compete in DARPA’s Subterranean Challenge. This could be used for search and rescue missions, so this year the Pi Day Quiz is all about engineering for rescues.

1) A 100m long rope is wrapped around a perfectly round tree which is 2m away from a 90m deep hole.  Approximately how much rope is wrapped around the tree with a 1m diameter, if four wraps are used?

2) Will the rope from question 1 reach the bottom of the hole?

3) A rope is wrapped around a perfectly round tree. If the amount of friction which holds the rope is (Number of Wraps x (coefficient of friction of rope on tree) x circumference of tree) + (Number of Wraps-1)x(coefficient of friction of rope on rope) x circumference of tree)), what happens if we go from 3 wraps around the tree to 4?

In this example, use these values:
diameter of tree=20 units
coefficient of friction of rope on rope = 0.5
coefficient of friction of rope on tree = 0.3


4) A rope is wrapped around a perfectly round tree. What happens if we find a tree which has a diameter of 24 units instead of 12 units? Use the equation the amount of friction which holds the rope is (Number of Wraps)x(coefficient of friction of rope on tree) x circumference of tree) + (Number of Wraps-1)x(coefficient of friction of rope on rope) x circumference of tree)).

In this example, use these values:
Number of Wraps=3
coefficient of friction of rope on rope = 0.5
coefficient of friction of rope on tree = 0.3

5) Caver Static Rope is designed to minimize rope stretch. As a result, it is stronger when straight than when in a knot. Design a rope hauling system that only uses three knots.

6) Design a rope hauling system using gears to lift ten times the weight that can be lifted with no gears.

7) A rappel rack is a device which winds rope around metal cylinders, known as bars, to create friction to control the speed of rope moving through. Using the equation friction = (coefficient of friction of rope on bar)x(rope on bar contact area), how much more friction would there be if the diameter of the bars were doubled?

8) Design a hauling system which only uses rope, anchors, and pulleys to lift ten times the weight that can be lifted using only rope.

Edwin D. Reilly at the Edison Tech Center

“Edwin D. Reilly”

Edwin D. Reilly, a long serving Board Member of the Edison Tech Center, passed away on August 1st at the age of 87. While growing up in Troy, he often visited the General Electric Plant in Schenectady where his father was employed. It provided him with the opportunity to meet many pioneering scientists and engineers.

Ed Reilly
“Ed” has been a long standing board member at the Edison Tech Center and also an important leader at the Schenectady County Historical Society.

Ed was the 1950 class valedictorian at Troy’s Catholic Central High School. He continued as an ROTC member and graduate of Rensselaer Polytechnic Institute. After starting his career at the General Electric R&D Center, he was called to active duty. He spent two years in Washington with the National Security Agency. It introduced him with the potential for computers. He returned to Schenectady to pioneer computing for nine years at the Knolls Atomic Power Laboratory, while completing a PhD at Rensselaer. He joined the University at Albany in 1965 to establish the Computer Center and Chair the Computer Science Department. He co-edited “The Encyclopedia of Computer Science” and wrote text books.

Upon graduation from RPI, Ed had wed Jean, his childhood sweet heart. They would raise six children. Meanwhile he was elected the Niskayuna Town Supervisor. He served from 1970 to 1979 and again from 1989 to 1997. He oversaw the design and construction of the Niskayuna Town Hall. It has been posthumously renamed in his honor.

Ed was a frequent contributor to the Schenectady Daily Gazette with topics ranging from history, politics, industry, sports and science. Along with serving on the Board of the Edison Tech Center, Ed was President of the Schenectady County Historical Society. He served as a Trustee of the Schenectady County Library and was a leader within his church.

Edwin D. Reilly was truly a remarkable person and citizen. He was admired and will be missed by many.

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2018 Edison Tech Center Pi Day Quiz

It’s time for the annual Edison Tech Center Pi Day Quiz. Submit your answers by private message on Facebook.

1) An electric quartz crystal clock circuit is
designed. Will the clock maintain the correct
time better if it is a 24 hour clock or a 12 hour

2) The water supply to the Edison Tech Center
starts as a three inch diameter pipe, which is
then connected to a two and one half inch
diameter pipe, which is then connected to a one
inch diameter pipe. Given a constant water
pressure outside the building and ignoring
water friction, what is the speed of the water
inside the different pipes?

3) The Edison Tech Center milling machine
surface can be moved by turning a four inch
diameter handle. One rotation of the handle
moves the machine surface 60/1000 of an inch.

4) An automobile tire decreases in diameter due
to friction on the road. What percentage
odometer error does a 2 mm decrease in
diameter cause on a 381 mm diameter tire?

5) Water friction decreases as pipe diameter
increases. How much water friction is there in
the one inch diameter pipe compared to the
three inch diameter water pipe?

6) An alcohol stove is made out of a cat food can
with a circumference of 20.32 cm. 5 mm holes
are made around the circumference of the can,
spaced 15 mm apart, center to center. How
many holes can be put in the can?

7) A shower has a constant water pressure
supplied. What is the difference in output for a
showerhead with 1 mm holes versus 2 mm

8) Let us model the Mohawk River as a pipe.
When ice builds up on the river, it decreases
the diameter of the pipe. If there is a constant
supply of water in the river, and the ice blocks
half of the diameter of the river, how much does
that change the flow of the river?


New ETC Videos in 2017

The Edison Tech Center has over 200 videos available free to students via YouTube. This year at the Edison Tech Center we have put out excerpts of larger videos on YouTube. Here are the new videos:

Frank Wicks talking about oil, batteries, renewables and electric cars. His discussion with Ernie Tetrault reflects many talking points of the time at around 2008. Some things have changed but many points remain the same.



Here is an interview with Harold Gauper talking about design of electronics at the beginning of the electronic age. They had to deal with radio interference for the first time.


Rudy Dehn talking about radar history from 1937 until 1955. He shows us the L128 klystron tube developed by General Electric:


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Theater Organ at Proctors – Electronics and Pneumatics

Theater organs in the early 20th century came at a fascinating crossroads of technology when electricity was combined with centuries old pneumatic technology. The result was the last great mechanized orchestras before vacuum tubes, high quality sound recording and electronics replaced actual instruments. “Goldie” in Proctors is a grand example of a working large theater organ. Retired GE engineers Carl and Frank Hackert have put in untold hours keeping Goldie working. Choosing engineering for your career has not just the potential to lead to a satisfying career, but also the potential to allow you to do amazing things with your hobbies and passions, assisting non-profits in everything from organs to, building schools for the poor, to sailboat restoration. A lifetime of experience in materials, electronics and systems thinking is a great asset to any non-profit. In this case #Schenectady engineers have been active with the American Theater Organ Society and local efforts to keep a monument to history alive.

Pi Day Quiz 2017

1) Building a wooden window frame, is it stronger to use a circular or an L-shaped bracket over the corner joint?

2) What is the minimum number of nails or screws needed to attach the bracket from Question #1 so that the frame is limited in how it can distort along two axes (X and Y axis)?

3) Does a spherical ice cube last less time, more time, or the same amount of time as a cubic ice cube?

4) Does a cubic ice cube cool the liquid it is submerged in faster, slower, or the same speed as a spherical ice cube?

5) An electrical circuit can be built to reduce frequencies higher than a ‘cutoff frequency’.  What is a formula showing the relationship between the capacitance of the circuit and the ‘cutoff frequency’?

6) An electrical cable is coiled for shipment and when installed still has a 2.5 cm diameter spiral to it.  How does that change the total length of the cable?

Electric City Bike Rescue in September

Last month our resident photog captured moments at the Electric City Bike Rescue. This operation services the public every Thursday at the Edison Tech Center. See our Contact Us page for updated hours.

Every year many tonnes of steel are wasted as it is thrown into landfills across the country. Much of the population has no knowledge of how to fix even minor problems on their bikes, so when they encounter a problem they just throw it away and buy a new one. Not only is this a waste of our planet’s resources, but it is also a shame considering many less fortunate people in our community could use the older bike. The Electric City Bike Rescue helps people understand mechanical basics through applied effort on their bikes.  Here are some photos.

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Volunteer Opportunities at the Edison Tech Center in Fall-Winter 2016

This fall the Edison Tech Center closed its displays in order to change them out. After a number of years we felt it was a good time to freshen up our public area. The Electric City Bike Rescue program continues each Thursday all throughout the winter.


Behind the scenes help – We are looking for people with a strong interest in technology and engineering who would like to help build the new displays and use their technical or trades background in this effort.

Bicycle Rescue Volunteers – If you would like to help on Thursdays please contact us and let us know you’d like to help with this program.

Submission of engineering papers and curriculum – If you’d like to publish your papers on our website or blog please contact us. We are looking for non-political, non-religious engineering papers which can look at history or current technological events. Many of our online resources have been enriched by experts in the area who added sections to our pages.

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