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Friday, March 28, 2014

Canals and STEM - Great Learning Resources


Canals
I grew up not far away from Clinton’s Folly, otherwise known as the Erie Canal. Completed in 1825, the canal was enlarged twice before the turn of the 20th century to provide access to larger ships and barges. Today, the canal is part of the New York State Canal System and is popular with recreational boaters.

While I was most fascinated as a kid by the abandoned sections of the Erie Canal that were in short driving distance from our house, today I know that canals are not just a historical curiosity; modern canals play a vital role as shortcuts in shipping. Some that are particularly important are the St. Lawrence Seaway, the Chesapeake and Delaware Canal, the Kiel Canal, the Suez Canal, and the Panama Canal.
I grew up not far away from Clinton’s Folly, otherwise known as the Erie Canal. Completed in 1825, the canal was enlarged twice before the turn of the 20th century to provide access to larger ships and barges. Today, the canal is part of the New York State Canal System and is popular with recreational boaters.

While I was most fascinated as a kid by the abandoned sections of the Erie Canal that were in short driving distance from our house, today I know that canals are not just a historical curiosity; modern canals play a vital role as shortcuts in shipping. Some that are particularly important are the St. Lawrence Seaway, the Chesapeake and Delaware Canal, the Kiel Canal, the Suez Canal, and the Panama Canal.
Science Connection: Canals and Geology
Ships have been an efficient mode of transporting cargo for thousands of years. For ships that navigated on rivers, geology has often presented obstacles. The ships had to go where the rivers went. The first person to change this was Emperor Yang of China, during the Sui Dynasty—1400 years ago. The Yangtze and Yellow Rivers, China’s main waterways, run from west to east. Yang wanted a reliable way to bring rice from southern China to feed his armies, in the north. The result was the Grand Canal, 1100 miles long when it was completed in the early 600s.

As if the constraint of having to go where the river was going wasn’t enough, sometimes geology conspired against ships and threw up a waterfall or some rapids. The abundant source of power these offered led to the development of industry and created a need for efficient transportation. Transportation downstream was easy, but what about taking goods upstream, past the rapids? Enter the golden age of canals, during the Industrial Revolution.

Today canals serve a number of purposes beyond transportation, including irrigationand hydropower generation. It is quite likely that you benefit somehow from the use of a canal every day, either in the electricity you use, the produce you eat, or the imported goods that may have passed through a canal on their way to you.
Technology Connection: Canal Traffic Control
Canals were not designed to support two-way traffic along the whole of their lengths. Many canals experience changes in elevation that necessitate the use of locks, and most locks aren’t designed to accommodate lots of ships at once. An efficient way to monitor and control canal traffic is a necessity. The new traffic control system for the Panama Canal includes 24 cameras that observe ships in the canal and allow controllers to view telemetry and GPS feeds from the ships. Other common elements of canal traffic control include radar and lock automation systems. If you’re interested in shipping traffic, have a look at this website, which lets you zoom in on any part of a map of the Earth to see what ships are in the area. You can click on each icon to see details about the ship such as type, size, year of construction, speed, destination, and recent port calls.
Engineering Connection: Locks and Ship Lifts
Since the completion of the Panama Canal in 1914, the dimensions of its locks have dictated the maximum size of cargo ships. Ships that are built to fit exactly in the Panama Canal locks are called Panamax ships. There are two sets of three locks on each side of Gatun Lake in the Panama Canal; three to lift ships up to the level of the lake and three to take them back down to sea level on the other side. Locks work with a set of pumps, valves, and drains to raise and lower the water level in an enclosure with gates at both ends. A simple animation and video of how the Panama Canal locks work can be seen here. Canal locks have operated in this way throughout history. An expansion of the Panama Canal is currently underway to build two more sets of locks in each direction.

Round locks were built where several canals with different water levels came together. This allowed for the barges to rotate in the lock to face the desired gate. A famous example of a round lock is at Agde on the Canal du Midi in France. The lock is no longer round because it was enlarged to fit bigger barges. A short animation of how the lock works, showing its original configuration, can be seen here.

An alternative to locks is a boat lift. These can take boats up and down a significant height in a single stage. Two good examples of boat lifts are found in the United Kingdom. The Anderton boat lift is a restored 19th-century boat lift between the Trent & Mersey Canal and the River Weaver. It has two counterbalanced basins that operate on a hydraulic lift system. Originally constructed in 1875 to help move salt from the interior of England to the coast, it was restored in the late 20th century and reopened to pleasure boat traffic in 2002. A video of the boat lift in action can be seen here. This kind of boat lift would be a good model-building project.

A modern solution to the problem of waterways at two very different elevations is found in Scotland, at the Falkirk Wheel. This boat lift is remarkable as much for its beautiful design as for its purpose. It opened in 2002 to reconnect the Forth and Clyde Canal with the Union Canal and replaces an earlier flight of locks that was removed in the 1930s. An explanatory video of the wheel in action can be seen here. This boat lift also operates on a counterbalance, but is a much more elegant design than a simple up-and-down lift. You can buy a model-making kit for the Falkirk Wheel from the Scottish Canals online store, for ₤19 (about $32), and they will ship to most countries.
Math Connection: Scale Models
Building scale models is a good math exercise for students who like to work with their hands. A number of practical examples for making scale drawings using ratios and proportions can be found here.

Another interesting math exercise for students interested in canals would be to figure out how much the water and the ship in a lock weigh together, and how much work must be done to lift the boat from one level to the next in a lock. A thorough description of these types of calculations for a variety of different types of locks can be found here.
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