Inclined Plane Vanderbilt Student Volunteers for Science Fall, 2004 Training Refresher Presentation

Important!!! Please use this resource to reinforce your understanding of the lesson! Make sure you have read and understand the entire lesson prior to picking up the kit! We recommend that you work through the kit with your team prior to going into the classroom. This presentation does not contain the entire lesson—only selected experiments that may be difficult to visualize and/or understand.

Introduction (pg. 1) What is a simple machine? –Object that allows us to do work more efficiently. –Work = force it takes to move an object a certain distance. –Main idea = compare amount of work it takes to move an object without a simple machine to amount of work it takes while using a simple machine Examples –Lever, pulley, wheel and axle, inclined plane, wedge, screw –Big machines are made of smaller simple machines –This lesson focuses on inclined plane, screw and wedge

I. Inclined Plane Inspect the spring scale. Note the side marked “grams” and the side marked “Newtons”. We are interested in the side measuring Newtons (N) as it is a direct measurement of force. Draw a right triangle on the board and identify the parts: base, height and hypotenuse. base height hypotenuse

I. Inclined Plane (cont.) Make a ramp using two blocks and a textbook. The two blocks form the height and the book forms the ramp (hypotenuse). Measure the height of the ramp at the highest point and have the students note this number on their data sheet. Measure the length of the ramp (hypotenuse). Have the students enter this value on their data sheet.

I. Inclined Plane (cont.) Place the block so that it rests on the edge of the ramp. Attach the spring balance to the block and practice moving the block slowly and smoothly up the plane. Tell students to try to keep the force (pulling the block up the ramp) consistent. Tell the students to record the force readings on their observation sheet.

I. Inclined Plane (cont.) Have the students measure the force it takes to lift the block vertically without using the ramp. This is done by simply hanging the block on the spring scale. Have the students record the force reading on the observation sheet. Ask students which method took more force.

II. Wedge (pg. 3) Wedges are typically used for splitting objects apart. They are a combination of inclined planes. Have students measure the base and height of the slimmer wedge. Place two wooden blocks marked “Wedge” on a flat surface about 2.5 cm apart. Place the slimmer wedge between the two blocks. Line up the mark on the wedge with the edge of the two blocks as shown on the right.

II. Wedge (cont.) Run the string between the blocks and hook it to the spring scale. Tell the students to pull the wedge through the blocks in a smooth and controlled manner. Tell students to record the force required to split the two blocks on the observation sheet.

II. Wedge (cont.) Repeat the experiment using the wider wedge. Ask students which wedge required less force to separate the blocks. Note that the thinner, slimmer wedge took less force to separate the blocks.

III. Screws (pg. 4) Tell students that a screw is an inclined plane (look at triangular pieces of paper). Students will test for the pitch of a screw. –Pitch: amount of space between the threads of a screw. –Typically, the smaller the pitch, the easier the work. Pass the sample screws to the students and have them observe the differences in pitches.

III. Screws (cont.) Have the students take the large PVC pipe and measure its diameter. Record the diameter on the observation sheet. Tell the students to line up and tape the red edge of the triangle against the red end of the pipe. Carefully wrap the triangle around the PVC pipe and secure the corner with a piece of tape.

III. Screws (cont.) Students should be able to measure the pitch of the formed screw. The highlighted hypotenuse will form a spiral around the PVC pipe. Have students measure the distance between two adjacent highlighted edges of the right triangle. Tell students to record the measurements of the pitch. Repeat the activity for the small PVC pipe. Refer to manual for detailed discussion of the results.