Applied Science - Technology (1A) Lab
 OBJECTIVES: Exploring simple machines and tools. Comparing different tools in the kitchen. VOCABULARY: gears machine screws tool wheel and axle MATERIALS: Students determine the simple machines that are used in tools.
 BACKGROUND: Simple machines are a part of the physics discipline of "mechanics." Simple machines change the direction of an applied force, change the strength of a force necessary to do a job, or does both. Simple machines can also be used to apply a force to a place that cannot otherwise be reached or applies force in ways that cannot be done without machines. The definition for "tool" overlaps that of "machine". According to Webster's dictionary, a tool is something held in the hand and used for cutting, hitting or digging, with things such as knives, saws, hammers or shovels. Tools can also be the working part of a power machine, for example, a drill bit. In other words, an item that is called a machine based on what it does, can be described as a tool based on how it is used. Students will be studying kitchen tools. There are three basic elements of simple machines including wheel and axle,  lever, and  inclined plane. All simple machines that will be discussed are a combination of these basic elements. PROCEDURE: Explain the principle of a lever. A lever is basically a simple machine consisting of a rigid body pivoted on a fixed fulcrum. Before beginning this exercise, it is necessary to explain the terms "rigid body" and "fulcrum". The most familiar lever is the see-saw. The rigid body is where the student sits, and the fulcrum is the base that supports the rigid body. Using a board and a fulcrum (half log), see if the students can figure out how to lift you.  Don't give them too many clues.  Try moving the fulcrum to different positions or having students of different weights.   A scissor illustrates a lever. The point at which the scissor opens and closes is the fulcrum.  Ask students to cut the letter L from a piece of paper.  Write lever on the L.Put some peanuts (Make sure no one is allergic to peanuts or nuts in general!) in a tray, ask students to crack the peanuts with a nut cracker.Peel an apple to show the students how the peeler moves like a lever.Put a boiled egg or a ball of playdough on the egg slicer, then slice the object by pulling down the top. Point out that levers help make it easier to lift, move, or break heavy or large objects.    Discuss screws. This is one case where the force being applied travels very far to make the insertion of a screw easier. Everyone knows what screws are but most children think that shop screws are the only kind. A cork screw and fruit twister illustrate a screw. If you have oranges, students can "screw" the fruit twister for some juice.  You can also use playdough instead of oranges. Ask students to twist the twister into the playdough.         Wheel and axles work by using the motion of a wheel to move objects with less friction. A rolling pin and pizza cutter can be used to illustrate wheel and axle.  Students can roll out playdough to a thin sheet.  Then cut it with the pizza cutter. Corn skewers can illustrate wheel and axle. To illustrate the corn skewers, put them in an apple (or other fruit) so students can see how you can easily turn the fruit.    Talk about how gears are used to change the speed of turning and to go around corners.  An ice cream scooper, can opener and eggbeater illustrate gears. Point out the gears and let the students turn the tools. You may want students to actually scoop some ice cream! Eggbeaters can be used to make bubbles in a tub of bubble solution.