Instructions
Take two pieces of aluminum foil cut into small 2″x2″ squares. Poke a hole in the center of each square, with one being a small hole and one a large hole. Next, go outside to see what comes out of a pinhole, using a business card or a piece of paper to reflect the light. You will use the foil and card to observe the effects (the spots of light on the card), then make sketches of the setup (with the light pathways, and the light on the screen) on a separate piece of paper.
You will observe two different cases, observing the Sun with your pinhole, and then a shadow from a distant tree.
Case 1: Sun as the sole object.
Put the pinhole about 2 inches (or 3 finger widths) away from the card. Observe, make sketches of the light from the large and small holes, and answer these questions:
Between the large round hole and and small round hole, which makes a brighter spot?
Between the large round hole and and small round hole, which makes a sharper spot?
Put the pinhole about 6 inches (or 1 hand width) away from the card. Observe and answer these questions:
What happened to the brightness of the spots?
What happened to the size of the spots?
Case 2: Sun and tree casting a shadow.
In this case, you want the shadow of a branch of the tree, not the middle of the tree. You need enough light to form spots with the pinhole on your card. Observe, make sketches of the light from the large and small holes, and answer these questions:
Put the pinhole about 2 inches (or 3 finger widths) away from the card. Observe, make sketches of the light from each hole. How do the spots from the original large and small round holes differ from the Sun-only case?
What happens to the spots from your holes as you move your card away from the foil?
Take photos of the sketches with observations.
