A Diderot Pictorial Encyclopedia of Trades and Industry
Dover Publications has reprinted a two-volume selection of Denis Diderot's 1751 L'Encyclopedie. This magnificantly illustrated reference touches nearly every trade and industry in the pre-Industrial Revolution 18th century, from cheese-making to blacksmithing, casting cannons to weaving textiles, and from wooden shoe manufacturing to intricate jewelry.
List Price: $29.95
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Hand Over Fist
The nautical expression hand over hand originated with English sailors as a literal description of the technique used in climbing a rope, or hauling in or letting out a sail. It is thought that American sailors changed the expression to hand over fist. The term has acquired its current figurative meaning of continuous, rapid advancement
From When a Loose Cannon Flogs a Dead Horse There's the Devil to Pay,
by Olivia A. Isil.
Available at LCMM, 802-475-2022.
|WHAT'S NEW AT LCMM
Students Raise the Mast on Philadelphia II
Our philosophy at LCMM is to take advantage of every learning opportunity the museum can provide. When we learned our first school group of the year was studying simple machines we decided to have them help step the mast! We like the challenge of modifying our existing education programs to better meet educators' learning goals.
Philadelphia II is out of the water this year for routine maintenance, but she is still accessible to visitors and students as we recaulk her seams, put copper plating on the hull, and replace the rigging. To make the experience more memorable, we decided to step the mast and put up the rigging, even while the boat is on the trailer.
To perform this task, LCMM staff rigged a set of "sheer legs", essentially an A-frame, to straddle the position of the mast. This allowed a "pick point" for the raising of the mast. These fourth and fifth graders from Shelburne Community School guided the base of the mast by hauling on tag lines, run through blocks (or pulleys) on the deck.
In addition to these energetic students, we could not have done this task without the help of another tool: mechanical advantage. To raise this 600+ pound mast and rigging high into the air, we used a chain hoist, block and tackle, levers, and wedges. Learn more about mechanical advantage below.
Thank you, Shelburne Community School!
These Shelburne students visited LCMM to participate in the field trip 1776: The Revolutionary War in the Champlain Valley. As part of this program, they learned how boats like Philadelphia were built using traditional hand tools, visited an 18th century blacksmith shop, and discovered how Benedict Arnold led this fledgling fleet into battle in the fall of 1776. These students are studying simple machines, so we adapted our program to include the special activity of stepping the mast. Call us to see how we can tailor our program to your special curriculum!
|DID YOU KNOW?
Simple Machines On Board Boats:
Don't Work Harder - Work Smarter!
Boats are a great place to learn about simple machines. We use all sorts of mechanical advantage aboard our Revolutionary War gunboat Philadelphia II in order to make our jobs easier. Moving the sails, stepping the mast, moving and using the guns: all would be impossible without the use of simple machines.
Lever: In order to change the direction that the gun fires (in order to target the sails, the hull, or the people in between) sailors use a lever to pivot the gun at its fulcrum point. We use a hand spike (essentially a five-foot long square stick) to lift up one end while a wedge is placed underneath to prop it up to the appropriate height. In this manner, a single person can easily adjust the range of a 4000- pound gun!
Pulley: Well, on a boat, we call these blocks, but they are the same: a wheel with a groove in the outer edge to allow a rope (or line, as we sailors say) to pass across easily. A single block allows one to change the direction of the pulling. However, with two blocks, we begin to feel the mechanical advantage, as the weight is distributed between two points, decreasing the force necessary to half (and the line required is doubled). Likewise, with four blocks, the required force is quartered, but the line necessary is quadrupled. On Philadelphia II, we make use of block and tackle (the lines that go between the blocks) all the time: stepping (raising) the mast, setting the sails, and hauling the 2000- 4000 pound guns back and forth.
Wedge: A wedge is essentially an inclined plane. We use it when we build boats; axes, adzes, and knives are all wedges. We also tap in small wedges to accurately position objects such as the mast and the guns. Even the bow of the boat or the oars are wedges, pushing the water out of the way.
Screw: The screw is an inclined plane in the round with a wedge at the tip. We use them in boatbuilding in the form of an augur (our cordless drill!) for drilling holes for fasteners.
There are loads of uses for simple machines in the boating world. Modern boats use them, too: next time you're near or on the water, check it out!