Transverse Wave Demonstrator
Object: To construct an inexpensive device to demonstrate transverse waves.
Materials: craft sticks, string, hot glue guns and, scissors
Procedure: Take two craft sticks, overlap them by about one each, and glue them together. Make about 50 pairs. Cut about two six foot lengths of string. Stretch the strings into two parallel rows about one to two inches apart. Glue the pairs of craft sticks to the strings. Separate the pairs about one inch from each other. Keep the rows straight. Leave about one foot of string at one end and use this to attach the wave demonstrator to the ceiling or wall. With the wave deonstrator freely hanging tap it and a transverse wave should be created.
Reference: The information for this lesson was obtained from a workshop sponsored byThe American Association of Physics Teachers
Materials: duplicating paper, tape, and scissors
Procedure: Using duplicating (or notebook) paper cut a strip of paper lengthwise about one inch wide. Twist the strip 180 degrees and tape the ends together so that loop is made. Take a pen or pencil and start drawing a line lengthwise along the length of the loop. Predict what should happen. Continue drawing the line and see what actually happens. If done correctly the line should have continued on both sides of the loop. Take the scissors and cut along the line. Predict what will happen. If done correctly a loop twice as long as the first loop will be created. Again draw a line lengthwise along the new longer loop. Take the scissors and begin cutting along this line. Predict what will happen. If done correctly two intertwined loops will be formed.
Using an Overhead Projector to Demontrate Object and Image Realtionships.
Most classrooms have access to an overhead projector which can be utilized to demosntrate object and image relationships.
Arrange the ovehead so that a clear image is projected on the screen. Place a common object such an eraser, pencil, stapler, etc., on the overhead. Measure the length of this object and then measure the length of the image projected on the screen. Dividing the length of the iamge by the length of the objecct will give the magnification.
Now measure distance from the object to the lense in the head of the projector. This ic called the object distance. Then measure the distance from the mirror in the projector head to the screen. This is called the image distance. The image distance divided by the object distance will also give the magnification. Furthermore, the product of the image distance times the object distance divided by the sum of the image distance plus the object distance will give the fiocal length of the projector.
Try moving the projector closer to the screen. The image will diminish as the object distance remains about the same but the image distance decreases. This decreases the magnification. Movng the projector backwards will increase the image size as the image distance is increased.