Advance Preparation and Setup

Make copies of the Object and Image Distances and Graph Paper, for each student. If you assign Question 5 from Physics To Go, make an additional copy of the Graph Paper for each student. If possible, find a large-diameter mailing tube to make the forms for the mirrors used in the ray-tracing. Cut a section about 5 cm high. Give each group a complete section and also one cut in half (to be the form for the concave lens). If it is necessary to use a flashlight as a light source, you will need a very large-diameter form and a large piece of mylar to trace the parallel rays, because the flashlight beam will spread out so much. When the students investigate real images, use a large, well-shaped concave mirror so the image will be bright and clear. A cosmetics mirror with a diameter of about 15 cm works well. If your students use lasers, collect large pieces of cardboard to use as backstops.