Pulleys use two basic materials, grooved wheels and rope/string, to pull a load up and down. Creating this simple machine allows the user to put forth approximately half of the effort normally required to lift or pull an object. Pulleys can be fixed, movable, chain-hoisted or made from two or more units (compound pulleys). Fifth-graders can use a two-foot (minimum) length of thin rope and a store-bought grooved wheel to create their own pulley simple machine. Thread the rope through the groove on the wheel. Attach the top of the wheel to a solid surface such as a frame or shelf. An adult should help the student to secure the wheel with a hook or nail. Tie one end of the rope to any weighted object. Use the other end to pull or lift the object up and down.
Students can create a lever project that uses a fulcrum and rod to lift a small load. A fulcrum, or pivot point, is a support that goes under the rod to help move an object or load. You may use a wooden dowel or metal rod over top of a wedge shaped object (try a triangular rock or plastic wedge). Choose a weighted load such as a large rock, heavy toy or even a shoe to place on one end of the rod. Position the wedge object (i.e., fulcrum) at different points under the rod and try lifting from the side opposite the load. You should find that when the fulcrum is closer to the load it is easier to move.
Inclined planes are sloping pieces of solid material such as wood or plastic that can make transporting objects easier by the degree or angle of elevation. Ramps, slides and hills are all examples of inclined planes. Make a fifth-grade science experiment using this simple machine by setting up an inclined plane made of propped up school books or wooden boards. Make a pile of at least three or four thick books/boards. Use another book/board leaning against the pile to create an inclined plane. Fill a plastic sandwich bag with a weighted material such as marbles. Tie a cut rubber band to the top of the bag. Lift the bag, by the rubber band, straight up to reach the top of the book stack. Measure the length of the stretched rubber band with a ruler or measuring tape. Repeat, but this time drag the weighted object up the inclined plane by the rubber band. Measure the length. Compare the two measurements to explore how the inclined plane may make work easier.
Screws are an incredible simple machine that can be found almost everywhere. A screw combines an inclined plane that is wrapped around a solid pole. These machines function to hold objects together or lift loads. Fifth-graders can try this simple machine science experiment from the Franklin Institute to explore how a screw works. Measure and draw a right angle onto a piece of construction paper. The resulting triangle represents an inclined plane. Color the long, slanted edge of the triangle with a bold marker. Press or tape the shorter, straight side of the triangle to the side of a pen or pencil. The pen or pencil acts as the solid pole for the screw. Evenly wrap the paper around the pen or pencil until the entire triangle is wound up. The marker line will spiral around the pencil, demonstrating how a screw is made from an inclined plane.