Reflection, Refraction, Diffraction

Reflection, Refraction, Diffraction introduces students to these three properties of light. Students will discover how light behaves differently when it encounters different kinds of objects. If it reaches a very smooth object, it reflects. If it passes through one medium to another, it refracts. And sometimes, it bends around an obstacle in its path, or diffracts.

There are a few different suggestions or alternatives that you can use listed in the “Options for Lesson” section. For instance, you could obtain a laser pointer or flashlight and a glass of water to use as an object lesson to illustrate how light behaves under unique circumstances.

What our Reflection, Refraction, Diffraction lesson plan includes

Lesson Objectives and Overview: Reflection, Refraction, Diffraction teaches students about how light reacts in different settings. While students may be familiar with reflection and refraction, diffraction might be a new concept to them. Students will be able to define each of these three terms and explain their meaning. They will also be able to describe the traits of these three properties of light.

There are four pages of content in this lesson. At the start, students will learn all about light. They will discover that light is really fast, that it travels at 186,000 miles per second! They will also learn that light can travel through liquids and gases, but it can’t pass through solids. This introduces students to how the properties of different objects cause light to react in a certain way.

The lesson defines reflection as light bouncing off a surface. The amount of light that reflects off the object depends on the object’s traits. A mirror, for example, is so smooth that it easily reflects light. The lesson continues on to define refraction as a wave changing direction when moving from one medium to another. This is what happens when you put an object in water. The object looks distorted because of the various angles of the light waves.

Finally, students will learn about diffraction. Diffraction occurs when a light wave stays in the same medium but bends around an obstacle. The lesson hows a couple diagrams of what this would look like.


The activity requires students to work with a partner. Students will create a poster board that shows the three properties of light. They should include diagrams, text, images, and other helpful resources to illustrate each property. They will then present the poster to the class.


There are two parts to the practice worksheet. For the first section, students must write whether each picture shows an example of reflection, refraction, or diffraction. There are nine pictures total. Then, there is a list of 10 prompts from the lesson. Students must write which property the prompts relate to. For instance, “a prism” relates to refraction. And “bends around an obstacle” relates to diffraction.


The homework assignment splits into two parts as well. The first 10 questions require students to match words in a word bank to the correct statement. For the second part, they must tell whether the statement is true (T) or false (F).

Additional information


4th Grade, 5th Grade, 6th Grade



State Educational Standards


Lessons are aligned to meet the education objectives and goals of most states. For more information on your state objectives, contact your local Board of Education or Department of Education in your state.