What is the principle of light used in hand shadow games?

The principle of straight-line propagation of light in air.

The principle of hand shadow play is that light travels along a straight line, the part of the hand that blocks the light is black, and the rest is bright, thus forming a shadow. If you use transparent glass to block the light, then the shadow will not form, or the shadow will be very shallow, because the light can penetrate.

Light travels in a straight line in the same uniform medium, which is usually called straight line propagation of light. It is an important foundation of geometric optics and can solve the imaging problem simply. The human eye determines the position of an object or an image according to the straight-line propagation of light, which is a part of physical optics.

The advantages of this game

Hand shadow games can not only mobilize children's senses such as listening, speaking and thinking, but also develop hand muscle groups. Finger activities can develop children's right brain and promote the coordinated development of left and right brains. Frequent finger movements can make children more dexterous and spiritual, and can also cultivate children's language expression ability.

For children before 1 year and a half, the change of hand shadow can help them know the shape and size; When a child is about 3 years old, he can play finger games step by step and exercise the small muscle groups of his fingers to improve his flexibility, accuracy and control.

This is very important for developing intelligence. It can enrich children's imagination and cultivate their creativity. Parents and children play hand shadow games while arranging stories, which can not only increase parent-child interaction, but also help their babies improve their language expression and performance skills. And hand shadow games are also very suitable as parent-child games before going to bed.