5 light experiments for kids at home (inspired by Isaac Newton)

A rainbow on the wall, a pencil that looks bent in water, or a changing shadow can make your child ask, “How did that happen?” Follow that question with five short investigations into light, color, reflection, refraction, and shadows.

These light experiments for kids at home use ordinary materials and leave room to predict, try, and notice. An adult should supervise every activity. The point isn’t a perfect result. It’s giving your child a reason to look closely.

If you’d like a story to begin with, find the Isaac Newton picture book here → and meet the curious thinker behind many of these questions.

Why Newton looked closely at light

In the 1660s, Isaac Newton investigated what happened when sunlight passed through a glass prism. White light spread into a band of colors, or a spectrum. Different colors bend by different amounts, so they separate. The prism did not create the colors; Newton’s questions helped him test what he saw.

A kid-friendly light vocabulary

A light source makes or emits light. The Sun, a flashlight, and a lamp are light sources. Reflection is light bouncing from a surface, while refraction is light changing direction as it moves from one material to another, such as from air into water.

A shadow forms where an opaque object blocks light. “Opaque” means light cannot pass through it easily. Objects look colored because they reflect some kinds of visible light more than others.

Before you start: safe light play for ages 4–8

An adult should set up and supervise each activity, especially around water, mirrors, scissors, glass, or small objects. Use a flashlight or indirect daylight. Never use a laser, ask a child to look directly at the Sun, or point a beam into anyone’s eyes.

Use plastic when you can. Check prisms and mirrors for chips or cracks, work on a tray or towel, and let an adult handle cutting. Keep small pieces away from younger children.

The simple investigation routine

Before each trial, ask, “What do you predict?” Afterward, ask, “What did you notice?” and “What could we change?” Try changing one variable at a time, such as the distance from a light source or the angle of a mirror.

If an effect is faint, move to a shaded wall instead of using a brighter or hotter light. A cool LED flashlight is enough for these hands-on STEM activities.

Experiment 1: Split white light with a prism

This Newton prism experiment lets your child observe white light spreading into a spectrum. It echoes Newton’s investigation without claiming to copy his exact setup.

What you’ll need

You’ll need an adult-held flashlight or a bright patch of indirect sunlight, a small triangular glass or plastic prism, and white paper or a pale wall. Books can steady the materials.

No prism? Try a clear glass of water as an optional alternative. The container’s shape, light source, and angle affect the result, so a rainbow is not guaranteed. Use plastic if it is safer for your setup.

How to try it

1. Shade the room slightly while keeping the setup safe and indirect.
2. Aim the flashlight through the prism toward the paper, then rotate the prism slowly.
3. Ask your child to predict what might appear before a color band reaches the paper.
4. Move the paper a little farther away and compare what you see.
5. If you use water, shine light through the side of the container toward a wall. Treat any color separation as an optional observation.

What is happening?

White light contains many visible colors. In a prism, each bends a slightly different amount, so the colors spread apart. The prism separates light that was already mixed together; it does not manufacture colors.

The result may be faint or absent. The prism’s angle, the paper’s distance, and the flashlight all matter.

Ask a Newton-style question

Ask, “What changes when you turn the prism: the light, the prism, or where the colors land?” Your child is practicing Newton’s habit of changing one part and watching carefully.

Experiment 2: Make a pencil look like it bends

This activity makes refraction visible and introduces a central idea in optics for kids: light can change direction between air and water.

What you’ll need

Gather a clear cup or bowl, water, and a pencil, straw, or straight craft stick. Choose plastic if your child might knock the container over. Put it on a tray or towel.

How to try it

1. Fill the container about halfway with water.
2. Place the pencil in at an angle, leaving part of it above the water.
3. Look from the side and ask whether the pencil still looks straight.
4. Change your viewing angle and the water level. Draw what changes.

What is happening?

Light travels at different speeds through air and water, so it changes direction at their boundary. Your child’s eyes trace the returning light in a straight line, making the submerged section appear shifted. The pencil itself is not bent.

Wipe spills promptly and keep the container away from the edge of a table. Don’t let a child run with the pencil or hold it near someone’s face.

Experiment 3: Bounce a flashlight beam with a mirror

Reflection gives light a new path. Your child redirects a flashlight beam toward a target by changing a mirror’s angle.

What you’ll need

Use a child-safe flashlight, a small unchipped mirror or reflective metal lid, masking tape, and paper with a simple target such as a star or circle. A plastic mirror works well. An adult should handle a glass mirror.

How to try it

1. Tape the target to a wall or place it flat on a table.
2. Shine the flashlight at the mirror from a short distance, with an adult controlling the beam.
3. Tilt the mirror until the reflected spot reaches the target.
4. Move the target or flashlight slightly and try again. Ask which angle changed.

What is happening?

Light reflects, or bounces, from the mirror. A smooth surface sends much of it in one direction, while a rough surface scatters it. The mirror gives the light a new path.

Never shine a flashlight or reflected beam into anyone’s eyes. Don’t use a laser pointer. Stop if the mirror is cracked or chipped.

After testing reflection, your child may be ready to ask more questions about the person who tested light so carefully. The Isaac Newton picture book is a warm way to continue that conversation.

Experiment 4: Chase a changing shadow

A shadow shows how light is blocked. Its size and direction depend on the positions of the light source, object, and surface.

What you’ll need

Gather a flashlight, a small opaque toy or household object, white paper or a light wall, masking tape, and a pencil or crayon. Choose a stable table setup so the flashlight doesn’t roll.

How to try it

1. Place the object between the flashlight and the paper or wall.
2. Trace the shadow’s outline or mark its edge with tape.
3. Move the flashlight closer and farther away while keeping the object still.
4. Move the object closer to the wall, then farther away, and compare the outlines.
5. Change the flashlight’s angle and look for the shadow’s direction to change.

What is happening?

An opaque object blocks some light, so the wall behind it receives less. The shadow often looks larger when the object is closer to the light, but all three positions and sizes matter.

Use an LED flashlight that stays cool. Keep cords out of walkways, and do not use a candle or hot lamp for this activity.

Experiment 5: Spin a Newton-inspired color wheel

This color activity explores what our eyes experience when colored sections change quickly. It models Newton’s color investigations without claiming paint and light mix identically.

What you’ll need

You’ll need paper or cardstock, a pencil or paper fastener, rainbow-colored crayons or markers, a cup for tracing, and adult help with scissors. Use broad sections.

How to try it

1. Have an adult trace and cut a circle.
2. Divide it into broad sections and color them red, orange, yellow, green, blue, and violet.
3. Make a center hole and mount the wheel on a pencil, or spin it carefully on a smooth tabletop.
4. Compare the slowly turning wheel with the quickly turning wheel.
5. Ask what colors seem to blur together and whether the result changes with different marker shades.

What is happening?

As the wheel turns quickly, your eyes receive light from changing sections in rapid succession. Colors can seem to blend or look paler. The result depends on pigments, spacing, speed, and lighting, so it will not necessarily look white.

An adult should cut the wheel and supervise the pencil or fastener. Keep small fasteners away from younger children, and stop spinning if the paper flies apart.

Turn five experiments into one light lab

You’ve explored five effects: the prism separates colors, the pencil shows refraction, the mirror shows reflection, the shadow shows blocked light, and the color wheel models rapid visual changes. Together, these science experiments for kids show how light changes when it passes through, bounces from, or is blocked by something.

Make a “light detective” page with a prediction, drawing, and sentence about what changed. You can return to these light experiments for kids at home whenever your child notices a new light mystery. For another kind of investigation, try gravity experiments next. It focuses on a different force.

Questions that keep curiosity going

Ask, “Where did the light start?” “What did it bounce off or pass through?” and “What could we change?” Don’t grade the answer. A faint or unexpected effect still gives your child something useful to observe.

Where light leads next: Isaac Newton for kids

Newton’s story begins with questions. Your child doesn’t need to memorize “refraction” to do real science. Noticing, predicting, and testing are the heart of the lesson.

For the longer historical story, read the Isaac Newton biography. Teachers and homeschoolers can also find printables and additional age-appropriate material in Isaac Newton for kids resources. When you’re ready to connect the experiments to a read-aloud, visit the Isaac Newton picture book page.

After your child has chased a rainbow or moved a shadow, the Isaac Newton picture book can help them meet the curious person behind those questions. Find the Isaac Newton picture book here →