Summary
Overview
Everybody and everything that is opaque has a shadow. Shadows are fun to play with because you can change their shape and size or even make them disappear. In this lesson, students will first explore how shadows are made and how their appearance can be changed. Then students will use their gained knowledge to create and perform a shadow play.
Remote learning: Part 1 on this lesson plan can be conducted remotely. The Engage section of the lesson can be done over a video call, then students can work individually and independently during the Explore section of Part 1, using the Student Worksheet as a guide. Students might need a helper that holds the shadow puppet for them while they move the flashlight. A set of materials can be prepared in advance or students can use materials found around the house. End the lesson with a discussion over a video call during the Reflect section. You can encourage students to come up with a story for a shadow play, but it might be challenging for them to perform the play by themselves.
Learning Objectives
- Explain, with evidence, that opaque objects block light and cast a shadow.
- Understand how the size and shape of a shadow can be manipulated.
- Collaboratively create and tell a story using shadow puppets.
NGSS Alignment
This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:- 1-PS4-3. Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light.
| Science & Engineering Practices | Disciplinary Core Ideas | Crosscutting Concepts | |||
| Science & Engineering Practices | Planning and Carrying out Investigations.
Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence to answer a question.
Analyzing and Interpreting Data. Use observations (firsthand or from media) to describe patterns and/or relationships in the natural and designed world(s) in order to answer scientific questions and solve problems. Engaging in Argument from Evidence. Construct an argument with evidence to support a claim. |
Disciplinary Core Ideas | PS4.B: Electromagnetic Radiation.
Some materials allow light to pass through them, others allow only some light through and others block all the light and create a dark shadow on any surface beyond them, where the light cannot reach. Mirrors can be used to redirect a light beam. |
Crosscutting Concepts | Cause and Effect.
Simple tests can be designed to gather evidence to support or refute student ideas about causes. |
Materials
Materials per Student Group of 2–4:
- Light source, such as a flashlight or spotlight
- Blank wall
- Dim room
- Cardstock
- Pencil
- Scissors
- Wooden skewers or craft sticks (5)
- Clear tape
- Optional: Printed Shadow Puppet Template
Materials for Educator:
- Two opaque objects with different shapes that completely block the light
Optional - For Shadow Puppet Theater Option 1:
- Door frame or other space (ceiling) from which to hang a shadow screen
- Shadow screen: White sheet, cloth, or white drawing paper roll
- Large piece of cardboard to cover students behind the screen
- Safety pins or tape
Optional - For Shadow Puppet Theater Option 2:
- Large cardboard box
- Utility knife
- White drawing paper roll or parchment paper
- Tape
Background Information for Teachers
This section contains a quick review for teachers of the science and concepts covered in this lesson.The saying "where there is a shadow, there must be light" tells us that you need some kind of light source to generate a shadow. For example, a person's shadow that constantly follows it around on a sunny day is generated by the Sun (Figure 1). But shadows do not necessarily disappear with the Sun. Other light sources like the headlights of a car, a table lamp, or a simple flashlight can cast shadows, too. The brighter the light source, the sharper the shadows will be.
Figure 1. On a sunny day, everybody and everything casts a shadow.
Every light source emits light that travels away in a straight line called a ray. To cast a shadow, you need an object that can block the light rays. Whether or not the object casts a shadow depends on its material. Materials that are opaque, such as people or cardstock, block all incident light and result in dark and sharp shadows. Materials that are translucent, like frosted plastic, let some light through and might result in blurry or lighter shadows. Materials that are transparent, such as glass, let almost all light through and barely cast any shadow at all.
How can the size and shape of a shadow be changed? This can be done by either moving the light source or by moving the object within the light beam. Most light spreads out the farther it moves away from the light source (Figure 2).
Figure 2. Light rays spreading out from two different light sources.
The closer an object is to this type of light source, the more light rays it will block, resulting in a larger shadow. Changing the angle of the light source can change the length and shape of the shadow. A steeper angle results in a longer shadow. This is why shadows outside are very long near sunrise or sunset, but very short when the Sun is directly overhead at noon (Figure 3).
Figure 3. The appearance of a shadow changes with the position of the Sun.
The fact that the appearance of a shadow can easily be manipulated is exploited in shadow plays. Shadow play or shadow puppetry is an ancient form of storytelling. It involves cut-out figures or shadow puppets that are held between a light source and a translucent screen. By moving the puppets within the light beam, the shadow puppets can be animated so that they appear to walk, dance, or fight (Figure 4).
Figure 4. A puppeteer animates shadow puppets behind a screen.
In this lesson, students will first explore how shadows are made and how their appearance can be changed. Then students will use their gained knowledge to create and perform a shadow play.
