Objective:

To demonstrate how light is reflected and refracted by water.

Standards:

Properties of Earth Materials (physical and chemical properties of water), Light, Heat, Electricity, and Magnetism (light reflectance, refraction, and absorption) and Transfer of Energy (light transmission, refraction, absorption, reflection, and scattering).

Materials:

Small dish, one penny, and water.

Procedure:

Place the penny in the middle of the empty dish.

Set the dish on a flat table or desktop.

Have a student carefully keep their eyes focused on the penny as they slowly back up from the dish until its edge just blocks the view of the penny.

Instruct the student to not move as you promise them that you will make the penny “magically” reappear.

Slowly fill the dish with water.

Repeat above process with more students.

Science behind It:

As you add water to the dish, the penny will gradually come back into the view of the student. However, magic is not the reason this happens. Adding the water to the dish causes the light to be refracted, or bent from the penny around the edge of the dish. This allows the light from the penny to reach the eye of the viewer. Water causes light to be refracted in various ways that help or hinder our view of many objects.