In the exploration of shadow formation, by providing some experimental materials, students can use these experimental materials to create shadows and try to make some changes in shadows. Then, students can create shadows on the blackboard and observe what experimental materials are used in the process of creating shadows and what role they play. From this, three conditions of shadow formation are obtained: light source, barrier and screen. Ask the students to tell what are the three conditions of shadow in this picture through a picture, and test their mastery.
Then, by asking students what changes they have observed in their lives, students can say that the size, direction, shape and length of shadows will change. Then study them one by one through experiments. There is something in this place that has been bothering me, as if it has surrounded itself. The change of shadow direction length is caused by the change of light source. So what's the change in the light source? The illumination angle and direction of the light source change. How to introduce the concept of lighting angle to students? Children in grade three haven't learned the concept of angle, so they haven't known how to introduce it. Ask teachers for guidance! After drawing out the two factors, namely the illumination direction and the illumination angle, ask the students: What caused the change of the illumination direction of the shadow? Let the students say his guess, then we changed the direction of light source irradiation when verifying the direction of light source irradiation, so can we change the angle of light source irradiation together? No, this can cultivate students' thinking of controlling variables: when there are two conditions in an experiment that will affect the experimental results, only one of them can be changed, and the other condition remains unchanged. This is a commonly used control variable method in science. After exploring the change of shadow direction and length through experiments, the class content is summarized and applied through a game of making hand shadows according to passwords.
After the hand shadow production, the children are introduced to the interesting games of shadowless lamp and shadow production through the promotion part, so that students can have a sustained interest in shadow research.