Teach your preschoolers about the shadows cast by the sun at different times of day by creating your own sundial at school. Using a tree, lamppost or yardstick that is in the sun for most of the day, take your preschoolers outside in the morning when they arrive to mark the spot of the shadow on the ground with a stone or chalk. Go out with your preschoolers at midday to mark the shadow of the same figure, and again before the end of the day. Show your students the differences in the length of the shadows and explain that when the sun is at it's highest during midday, it casts the shortest shadows.
Tape a large sheet of light-colored paper to a wall in your classroom and set up a projector on the opposite side of the room facing the sheet of paper. Ask for a volunteer student to stand about halfway between the projector and the sheet of paper. Turn the projector on and turn the classroom lights off. Using a thick, dark pen, outline the student's shadow. Once you're done with the first outline, ask the student to take two or three steps backward toward the sheet of paper and outline his shadow again. This demonstrates how the size of a shadow changes according to how close or far away an object is from the source of light.
Teach students about how shadows change when the direction of the light source changes. Take a uniquely shaped object, such as a shoe or a twig. Ask each student to draw what he thinks the shadow will look like when the light shines on the front of the object. On a separate sheet of paper, ask the students to draw what they believe the shadow will look like if the light shines from the side. Once each student is done, demonstrate the difference between each shadow and compare these shadows with the drawings made by each student.
Teach your students how to identify the correct placement of shadows with this activity. Give each student four sheets of paper that each has a shape in the middle of the paper such as a square or circle. For each paper, ask the students to draw where a shadow would appear if the light source was coming from the upper right, upper left, lower right and lower left corners. You may use a visual aid and point to each corner as you say right or left so that the students know where the light source is supposed to be.