Steamship Portland Where’s the Energy? FOCUS TEACHING TIME Energy conversions One 45-minute class period, plus time for student research GRADE LEVEL 5-6 (Physical Science) SEATING ARRANGEMENT Groups of 2-3 students FOCUS QUESTION What energy conversions are involved in the oper- MAXIMUM NUMBER OF STUDENTS ation of a steam engine? 30 LEARNING OBJECTIVES KEY WORDS Students will be able to explain the basic operation Steamboat of a steam engine. Mechanical energy Kinetic energy Students will be able to identify and describe the Potential energy energy conversions involved in the operation of a Chemical energy steam engine. Electromagnetic energy Nuclear energy MATERIALS Electrical energy Small plastic bottles with a tops, one for each stu- Thermal energy dent group Energy conversion Rubber bands, one for each student group Sticks (or pencils), approximately 6 inches long, BACKGROUND INFORMATION one for each student group On Thanksgiving Saturday, November 26, 1898, Small cardboard juice or milk carton, one for the passenger steamship Portland left Boston each student group Harbor with 192 passengers and crew bound for Tape and scissors Portland, Maine. During the night, New England Empty cardboard paper towel rolls, one for each was hit by a monster storm with northeasterly student group winds gusting to 90 mph, dense snow, and tem- Sink or washtub filled with water peratures well below freezing. At 5:45 a.m. on the morning of November 27, four short blasts on AUDIO/VISUAL MATERIALS a ship’s steam whistle told the keeper of the Race (optional) VHS copies of “Great Ships: The Point Life-Saving Station on the tip of Cape Cod Riverboats” and/or the “Steamboats ‘A Comin!“ that a vessel was in trouble. Seventeen hours later, episode of “The Mighty Mississippi” (see Extensions) life jackets, debris, and human bodies washed 1 Steamship Portland – Grades 5-6 (Physical Science) Steamship Portland – Grades 5-6 (Physical Science) Focus: Energy conversions oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Energy conversions ashore near the the Race Point station, confirming ple routinely boarded steamboats to travel between that the Portland and everyone aboard had been port cities. But the paddle-wheelers had a serious lost in one of New England’s worst maritime disas- flaw: they were built long and narrow (the Portland ters. was 281 feet long and 62 feet wide), and this shape combined with a shallow draft (the Portland’s For 90 years, the location of the Portland wreck keel was only 11 feet below the water line) made was unknown, despite intense and continuing these ships extremely unstable in high seas. When public interest. Then in April 1989, members of the Portland steamed out of Boston Harbor into a the Historical Maritime Group of New England strong northeasterly wind, the captain could not found wreckage more than 300 feet deep that they turn back: to have done so would have placed the were certain had been the Portland. Because of ship broadside to wind and waves that would surely the depth, however, the discoverers were unable have capsized her. The only choice was to continue to obtain photographs or other evidence that to head northeast into the waves, and hope to ride could confirm their find. Thirteen years later, on out the storm. Four hours after her departure, a August 29, 2002, the U.S. Commerce Department’s vessel believed to have been the Portland was seen National Oceanic and Atmospheric Administration near Thatcher Island, about 30 miles northeast of (NOAA) confirmed that the wreck of the Portland Boston. But the Portland was apparently unable to had been found within NOAA’s Stellwagen Bank make much more progress against the storm: she National Marine Sanctuary. Using side-scan sonar sank about 18 miles southeast of Thatcher Island, and a remotely operated vehicle (ROV), scientists perhaps because of the intense, constant pounding obtained high-quality video and side-scan images that may have lasted for 24 hours or more. The loss in a joint research mission of the Stellwagen Bank of the Portland underscored the inherent instability of National Marine Sanctuary and the National sidewheel paddleboats. Sidewheelers were gradu- Undersea Research Center at the University of ally replaced by propeller-driven boats, which have Connecticut. a lower center of gravity. Built in 1889, the Portland was a state-of-the art In this lesson, students will study some of the sci- vessel. Eighty-two years earlier, Robert Fulton had ence behind steamboats, and build a simple pad- demonstrated the potential of steamboat technology dlewheel boat. when the Clermont, the first steamboat built in the United States, successfully completed its trial run LEARNING PROCEDURE from New York to Albany. Unlike sailing vessels, 1. Download a copy of “Historic Shipwrecks of the steamboats could travel great distances on reliable Gulf of Mexico: A Teacher’s Resource” from http: schedules, and for this reason quickly became the //www.gomr.mms.gov/homepg/lagniapp/shipwreck/. You may preferred means of transportation along major also want to download a copy of “The Portland waterways of the United States. Steamboats had Gale” from http://www.hazegray.org for more informa- a major influence on nineteenth century life in the tion on the Portland and the monster storm of United States and contributed to the development 1898. Visit http://oceanexplorer.noaa.gov for up-to-date of tourism, transportation of perishable foods and information on the 2003 Steamship Portland supplies, settlement of frontier areas, and growth of Expedition. the U.S. mail service. 2. Briefly review the story of the Portland and the Because they were propelled by large paddlewheels, gale of 1898. Discuss the role of steamboats steamboats could maneuver in waters that were too in development of the United States during the shallow for sailing ships. By the 1870’s, many peo- 1800’s. 2 3 Steamship Portland – Grades 5-6 (Physical Science) Steamship Portland – Grades 5-6 (Physical Science) Focus: Energy conversions oceanexplorer.noaa.gov oceanexplorer.noaa.gov Focus: Energy conversions 3. Have students construct the model paddle- had many more features that made them more wheel boat described on page 15 of “Historic efficient. Shipwrecks of the Gulf of Mexico: A Teacher’s • The source of energy for steam engines can Resource” (please note that this activity was be fossil fuels (which were originally produced adapted from “Water, Paddles, and Boats” by by photosynthesis, since these fuels are the Pam Robson). remains of once-living plants and animals), wood (also a product of photosynthesis), 4. Lead a discussion of the energy sources and nuclear reactions, or sunlight (one type of solar transformations that take place when the model generator uses a parabolic mirror to focus the paddlewheeler is operating. Students should sunlight onto a pipe containing water that is recognize that the initial source of energy is the heated to produce steam). person who winds the rubber band. The rubber • Energy conversions typically involved in the band stores this mechanical energy as potential operation of a steam engine are conversion of energy. When the rubber band unwinds, the chemical energy (in fuels) to thermal energy, potential energy is changed to kinetic energy conversion of thermal energy to mechanical that causes the paddlewheel to turn, pushing energy (by increasing the motion of water mol- against the water and causing an opposite reac- ecules), and sometimes conversion of mechani- tion by the boat (the boat moves forward). Ask cal energy into electrical energy (in the case of students to take this sequence farther back: they an electric generator). should recognize that mechanical energy from • Early steam engines used steam to move a the person winding the rubber band comes from piston inside a cylinder. This produced a back- muscles that are using chemical energy that came and-forth motion, which was okay for pumps, from food that ultimately can be traced back to but not as useful for propelling boats or turning photosynthesis that used electromagnetic energy machinery. Many devices were built to convert from the sun). back-and-forth motion to rotary motion. The Portland used what is known as a “walking 5. Tell students that their assignment is to prepare a beam engine” to make this conversion. A large written report on the basic principles of a steam diamond-shaped beam was mounted on an engine, including an analysis of the energy A-frame structure. One end of the beam was sources and conversions involved when a steam connected to a rod attached to the piston of the engine is operating. An alternative to a written steam engine. The other end of the beam was assignment is to give students a series of ques- attached to a second rod that drove a crank- tions to research as a basis for group discussion. shaft, which in turn caused the paddlewheels to rotate, propelling the ship through the water. Lead a discussion of students’ research results. • The piston-cylinder type of steam engine was Most of the following points should emerge dur- replaced by engines that used steam to turn ing this discussion: turbines. This is the type of steam engine found in many electrical generating plants today. • The basic elements of a steam engine are • James Watt is often credited with developing a source of steam (usually a boiler fired by the first steam engine, but Hero of Alexandria wood, coal, or other combustible fuel), a (who lived more than 2,000 years ago) device that is moved by the steam (such as a documented many of the principles upon piston inside a cylinder or a turbine), and a which the steam engine is based. The first means for converting the motion of the device operating steam engine was built in 1712 by into useful work.