Teaching Children About Light, Shadows, and
Reflections
Life on Earth depends on sunlight. Plants, at the bottom of the food-chain, need light in
order to grow. Animals either eat these plants or they eat other animals that have eaten
plants.
Bonus Science Information
(explore as appropriate)
Some animals (herbivores) eat only plants. Other animals
(carnivores) eat only animals. Other animals (omnivores) eat
both plants and other animals. (Many young children are aware
of these distinctions because of their interest in dinosaurs!)
In addition to being essential in creating the food that sustains life, light allows animals
to see.
Light moves faster than anything else; it travels through space at 186,000 miles per
second. At this speed, it takes sunlight 8 minutes (480 seconds) to reach Earth. There
are many types of light that human eyes cannot see; these include ultraviolet light,
infrared light, radio waves, X-rays, microwaves, and gamma waves.
Sunlight appears colorless, but it actually contains all of the colors that we see. It can
be split into a spectrum of light – red, orange, yellow, green, blue, and indigo. In 1665,
Sir Isaac Newton was the first scientist to split sunlight into the spectrum; he used a
triangular block of glass called a prism. When light passes through a prism, it is bent at
an angle and this separates the ‘colorless’ light into colors.
Bonus Science Activity
Be alert when it is rainy and sunny at the same time.
A rainbow is created when rain droplets act as natural prisms to separate
sunlight into bands of color.
On sunny days, rainbows can sometimes be seen in waterfalls and in
hose-fed sprinklers.
Light always travels in a straight line. It continues to travel until it meets something that
changes its path and then it bounces like a ball changing direction.
When light hits a very smooth (shiny) surface, it is reflected directly back in the same
direction it came from. When light hits any surface that is not smooth, it reflects back in
many directions.
When sunlight hits an object, some of its colors are absorbed and some are reflected.
The object takes on the color that is reflected. An object that appears to be blue absorbs
all the colors except for blue, and reflects the blue light waves.
Light can travel through some objects very well and cannot travel through some objects
at all. There are still other objects that light travels through somewhat, but not
completely.
Objects that light travels through completely are transparent. Objects that light travels
through only somewhat are translucent. Objects that light cannot travel through are
opaque. Window glass and clear water are transparent. Soapy water, colored or
pebbled glass, and Jell-O are translucent. Walls and most other everyday solids are
opaque.
A shadow is created when light hits a solid object that it cannot pass through. Shadows
occur in both sunlight and artificial light.
Reflections
Concepts:
When light hits an object it is reflected.
When light hits a rough object, it is reflected in many directions.
When light hits a smooth surface, it is reflected directly back the way it came.
Learning Goals:
In collaboration with an adult, children will investigate how light bounces or reflects off
of different surfaces.
Materials:
Flashlight
Mirror
Shiny metal spoon
Plastic spoon
Tin foil, smooth
Tin foil, crumpled then flattened
Other objects collected by children
Activity:
Working in a darkened room, point the flashlight at the different objects and talk about
what happens. Which objects reflect light directly back? Which objects reflect light in
many directions? Classify objects into two (shiny, dull) or three (shiny, dull, somewhat
shiny) categories.
Hold up the shiny spoon in front of your face like a mirror. Can you see your face? Try
the other side of the spoon. How are the reflections from the two sides the same? How
are they different? Talk about why they might be different. Find another spoon and
make predictions about how your reflections will look, then find out.
What Can Light Move Through?
Concept:
Light passes through some objects and is blocked by others.
Learning Goals:
In collaboration with an adult, children will test a variety of materials to see which ones
allow light to pass through.
Materials:
Flashlight
Wax Paper or Parchment Paper
Plastic wrap
Tissue Paper
Water
Cardboard
Colored cellophane
Other materials collected by children
Activity:
Predict whether light from the flashlight will pass through each material.
Try this:
Classify objects into three categories: transparent, translucent, opaque.
Talk about how the objects in the three categories are the same and different.
Introduce the word shadow. Shadows are formed when an object blocks light.
Shine the flashlight on the cardboard from different distances and at different
angles. Talk about how the shadow changes depending on the distance and angle
of the light source.
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