Bounce or Absorbed - Light Pathways and Interactions
- The students will explore different sources of light through observation to
establish a relationship between light, heat and color.
- Through the use of fickle foam-liquid crystal thermo-sensitive material-
and/or sun sensitive paper, students will begin to analyze the effects of light
and heat on matter and that color changes are a clue to the intensity of energy
being used or given off.
- Students will explore reflection and refraction and compare these properties
- Through the use of remote sensing images provided by NASA, students will
begin to identify where on the biosphere light is reflected the most, the
least, and how this information is useful.
Time Duration: four 50-minutes sessions
Grade Level: 8-11
scientific processes, energy, communication, comparison, inference,
classification, measurement, organization, evaluation and synthesis
radiant, incandescent, fickle foam, liquid crystals, heat, color, intensity,
reflection, refraction, opaque, transparent, translucent, texture, surface.
Grouping: Groups of 4 or 5
Materials Per Group:
- 2-3 flashlights
- mirrors (optional)
- liquid crystal thermometers postcards
- set of opaque/translucent/clear materials: papers, etc.
- jars empty or with water/ soapy water/ dirty water
- fickle foam
- recording chart paper or individual pages
- rulers and/or meter sticks
Materials Per Class:
- remote sensing images
- inflatable globe (12" diameter or more)
- book: Sun Up, Sun Down, Scholastic Press
- Ensure that the working area can be darkened for the use of
- Purchase liquid crystal thermometer post cards or plain fickle foam heat
sensitive material, enough to have one per each cooperative group station in
- Gather different sources of light: a candle, a flashlight, a fluorescent lamp
and a regular lamp. If you have access to different types of light bulbs, use
- Collect and cut into squares (approx. 8"x8") various types of materials: wax
paper, report plastic covers, plastic wrap, aluminum foil, sand paper etc. You
need a variety of transparent, translucent and opaque materials with textures
that are smooth or are textured.
- Gather other materials such as jars, leaves, dirt or sand, clay, colored
- Mirrors are optional. A good resource is a store that supplies decor vinyl
materials, for non-breakable plastic mirrors.
- Supplies: Science or nature related stores usually carry the liquid
crystal thermometer post cards.
- Technology: 3,2,1, Contact Video on Light/ Computers can be a tool to
graph or draw models of light beams, distance, angles of reflection and
Exploration of different materials for light refraction is important
prior to teaching any terminology, such as opaque, clear, etc. The students
will construct their own knowledge by discovery, comparisons and observations.
Then, the meaningful contextual words can be taught.
Prior to Day 2, the students should have background on the solar system and the
rotation of the earth. Activities with flashlights and students representing
the sun and the earth would be appropriate. This lesson can extend into the
upper grades to allow for discovery of the different angles of light as they
reach the earth, by measuring the angles of light with a protractor. You may
choose to use it as a demonstration, with guided questioning. Modify it to fit
your grade level.
Day 1: Exploring the characteristics of light from different sources:
- Light a candle as a demonstration and ask students to record/share the
characteristics they observe. Color, flame size, movement. Ask how far and in
which direction is the light of the candle traveling? How can we find out?
Depending on responses, you might facilitate the following discussion:
- Darkening the room, and placing a white paper from gradually increasing
distances away from the candle, (i.e. 5 cm, 25 cm, etc.) until the reflected
light off the paper is no longer visible. Measure and record.
- What else besides light is the candle emitting? How can we measure it?
Place a thermometer near the flame, at 5 cm, then at 25 cm, record the
temperatures, fill in a chart as a class model.
- Perform the same observations on different sources of light such as:
- a flashlight
- a desk lamp
- a flood lamp
- a fluorescent light
- a halogen bulb
- a colored light bulb (black, green, red, blue)
Allow students to observe, measure and record their data in groups, then to
share the information as a whole to reach conclusions.
Make a sample chart like the one shown below on the board, to show students how
to organize their data. For upper grades, you may ask students to design their
Light Source: Observations Distance beam Temperature
Candle Blue on the bottom 5 cm: very bright 5 cm: ....C.deg. 25
Yellow on top 25 cm: bright 50 cm:...C.deg. 50
Orange center cm: pale, dim 1 m: cm:...C.deg.
Shaped like an very faint 1.5 m: 1m:...C.deg. 1.5
upside down drop slight trace 2 m: ...m ...C.deg.: 2
Smoke, flickering... not visible m:...C.deg.
3. Based on the data gathered, what conclusions can be drawn? Which light is
the most efficient? Why? What relationships can be drawn about the type of
light, the heat it produces and the color it emits?
How do the light sources used in this exercise compare to the sun's
light and the energy that reaches the Earth?
Invent an experiment with the lamp and thermometers which could help you
understand more about how far heat (infrared) energy can travel.
Day 2: Analyzing the effects of light on matter/Earth:
- Recall the conclusions drawn based on the data gathering from the previous
day. Explain to students that through the next exercise, they will be able to
find out more about the effects of light on matter and how the sun's energy
affects the Earth.
- To demonstrate how energy can affect matter, we will use one of the models
widely known as sun sensitive paper. (It can be purchased through science
supply houses, or use fax machine paper or paper from a photo lab/processing
store). If any of these supplies are unavailable, use construction paper and
expose for a longer period of time (perhaps a full day).
- Place paper with an object or cut out figure covering a portion of its
surface. Put a rock or other heavy item on top, so it won't be blown away by
- Let the paper and object sit under the sun for 5-10 minutes. In the
meantime, read the story "Sun Up, Sun Down", Scholastic Press. Discover the
different ways light affects our daily lives.
- Go outside and gather the papers, observe and record the changes.
- Run the paper under water for a quick rinse and let it dry for another day.
How will it look? What do you think happened to the paper? What might have
happened if you left out in the sun for a longer period of time? A shorter
time? How can this model teach us about the effect of the sun's energy and how
it changes matter on Earth?
- Using the fickle foam, post card thermometers, globe and light source
(flashlight or lamp), make a model of the energy of the sun reaching the earth
as in Figure 1.
- Tape the postcards and fickle foam to the globe, one on the equatorial
region and one near a polar region. Place a third one in between the other
two. What does each object represent? Shine the lamp on it and record your
observations. How does the light energy affect the liquid crystal cards or
foam? What changes do you see?
- What does this tell us about the climate in polar, temperate, and
equatorial regions of the world and the people who live there? What do they
need to do to adapt to the changes in temperatures? How does incident solar
energy affect the land, the agriculture, the homes in different areas?
- How else does the light energy of the sun affect us on Earth? Brainstorm
How can the amount or intensity of light affect matter? How are color
and light energy related? Make a model or invent an experiment using a light
source and other objects to explain the effect of light on them.
Day 3: Explore reflection and refraction of light through different
materials. Establish an analogy between the information gathered through
the exercise and the use of remote sensing images.
[Ask the students to suppose they are a fish that shoots jets of water by
snapping its jaws closed at insects on low-hanging branches over the your pool
of water. Your eyes remain below the water, but your target is above the
water. What aiming adjustments do you, the fish, have to make in order to
knock the fish into the water? Illustrate the aiming problem by placing a
pencil in a jar of clear water and viewing it from the side. Have the students
find the name and habitat of the actual fish that uses this form of hunting.]
- Recall how the light affected the different paper materials exposed to the
sun's energy. Introduce the properties of reflection and refraction by guiding
students to shine beams of light on and through different materials.
- Give students squares of different cut out materials (listed under materials
section, except the glass jars and water containers.)
- Allow exploration to see how light would bounce or go through the different
- Facilitate and motivate students into exploring how they could record and
account for the differences between the materials and the way light passes
through them or not. Make a graph of materials that allow light through,
materials that don't, and those in between. Label the titles of the graph:
Most Reflective, Most Refractive, Both Refractive and Reflective.
- What else besides light are the sources emitting? If light doesn't go
through, where does the energy go? What does it turn into? Which tools would
we need to record this change?
- Distribute the jars with liquid in them. Allow for exploration, observe
and record information on the class graph.
- What conclusions can be drawn about the type of liquid in each jar, its
characteristics and the amount of light that can travel through it or bounce
off it? Share and record conclusions.
If you were to live in _____ (a region of the earth), what type of materials
would you use to build a house? Why?
Day 4: View remote sensing images.
Search for reflection and refraction clues. How is this information important
for the study of our planet? Understanding the information gathered through
remote sensing, based on the refractive and reflective properties of light and
the types of effects it causes on different surfaces.
- View remote sensing color pictures depicting reflective light from
different sources. Guide students in identifying the most/least reflective
- Go to the playground and identify from the ground which objects would be
identified as most reflective/refractive by a remote sensing plane flying above
at a given altitude. (Low enough to identify buildings).
- Use thermometers outdoors to place on different surfaces exposed to the sun
and record the temperatures. (Roof top, black top, bush top, fence top, grass
area etc.). What else would be important information from the ground to
identify the images from above? Would color of objects, weather conditions and
time of day matter? Why? Record the conditions named and the temperatures to
share with the class.
- Return to class and make a class graph to identify all the conditions
needed for the analysis of the remote sensing images.
- Look again at the remote sensing images and see how many of the factors can
be identified using the class chart. Did color, temperature, time of day and
weather conditions have a role in the pictures being analyzed? What
information can be seen on the remote sensing images that suggest these
Give students the opportunity to make an experiment using dirt, leaves,
water glasses, and fabric or paper on a foot square, exposed to the sun and
record their information. Then they need to design their own miniature map as
if seen from above, using the factors studied in the lessons.
Using transparent cups, dirt, water, sand and thermometers, students can build
mini-biosphere regions for analysis of temperature and humidity factors. The
cups can be placed at different locations for different exposure of the sun and
the data gathered can be recorded over a period of time, for more accurate
Example: Set up three cups, dirt filled, water filled and sand filled. Place
a set of three each on a northern exposure window and a western exposure
window. Record the temperatures of the cups over the Fall season and the
Winter season. Project what might happen during the Spring season. How did
the sun's light affect the cup biospheres? What temperatures surprises were
found? How did they compare from north to west exposure? Why? At what time
of day were the temperatures recorded? What would happen if they were measured
during a different time? Is this a variable or a constant? Which would be your
control? What other factors need to be taken into consideration when doing this
experiment? ( room temperature, air conditioning, heater proximity, etc.)
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