And Then There Was Light

Primary, Intermediate

  1. Students will explain that light travels in straight lines.
  2. Students will classify objects as transparent, translucent, or opaque.
  3. Students will observe properties of light including reflection and refraction.
  4. Students will make a prism and observe the colors of a spectrum.
  5. Students will name the colors of the spectrum in order.

Day 1

Background:

Your students work through a variety of hands-on activities to discover and understand the properties of light. They learn about and work with transparency, translucence, opacity, reflection, refraction, and absorption as you bounce a ball off of your chalkboard (to demonstrate how light is reflected), and bend, flash, mirror, and use a prism to put light through its paces at 186,000 miles per second.

Procedures: Day 1: Students brainstorm what produces light, what we use light for, and how light travels.

Motivation:

  1. Have the class brainstorm objects that produce light. Accept reasonable answer and write them on the board or have a student volunteer write them on the board.

  2. Have students brainstorm what we use light for. Write the answers on the board.

Teaching & Practice:

  1. Just as heat and sound travel, so does light. Light travels in straight lines. Sometimes it bounces off objects. We call this a reflection. Water, windows, shiny metal, and mirrors are just some of the many objects that reflect light. To further demonstrate that light travels in straight lines, use a small bouncing ball. Throw the ball at the chalkboard in a straight line in front of you. The ball will bounce off of the board back in a straight line to you. Next, throw the ball at the chalkboard at an angle. The ball will bounce away from the board at the same angle, but in the opposite direction. Explain that light travels in the same manner.

  2. Experiment with reflections.

  3. Give each child 1 small mirror. (Mirrors can be made from aluminum foil or mylar found in art stores. Fold the foil or mylar around a piece of oaktag and rub smooth.)

  4. Then have children draw or cut out magazine pictures that have symmetry -- stars, faces, flowers, etc. Cut the pictures in half. Have students put the mirror next to the half and see its reflection in order to complete the picture.

  5. Now have students draw shapes and designs, cut them in half, and switch with a partner. Students would then complete the drawing using a mirror.

  6. Next, have students hold up printed copy from a book or magazine to a mirror. What's different about printed text in the mirror? (It's backwards.)

  7. Have students try to write messages that can be decoded using a mirror.

Assignment:

Students should be able to demonstrate a basic understanding of how light travels, what objects produce light, and what we use light for.

Day 2

Background:

Procedures: Day 2: Students conduct hands-on investigations into transparency, translucency, and opacity of objects.

Set-up for Center One: This is a paper/pencil task dealing with light and reflection.

Student Instructions for Center One:
Light travels in __________________ lines.
Complete this diagram. How will light reflect off of the mirror?

Day 2: Lighting It Up: Transparency, Translucency, and Opacity

Set-up for Center Three: Have a prism set up to show the spectrum. Remind students not to touch the prism so that the spectrum will remain visible. Students will observe the prism and then write about the properties of light.

Student Activity for Center Three:
What is this glass triangle called? ________________________
When white light enters the prism, you see colors. Explain how this glass triangle works.

Set-up for Center Four: This center is testing basic recall of the order of the colors in the spectrum. Students should not be able to see prism while they complete this portion.

Student Activity for Center Four:
Draw and list the colors of the spectrum in order on the diagram below.

Motivation:

  1. Review Day 1 with the class.

  2. Light travels in a straight line, but can we see all light? Using a flashlight, shine the light against a book. Where is the light that is being shined on the book? Why can't it go through the book? Explain that when light travels and strikes an object, the object may let the light pass through it freely, the object may let only some of the light through it, or it may let none of the light through it.

Teaching & Practice:

  1. Break students into small groups. Have each small group search the room in an effort to find one object that light will pass through, one object that only some light will pass through, and an object that will block light.

  2. Make a three column chart out of butcher paper. Label one column "Lets light through;" label one column "Lets some light through;" and label one column, "Lets no light through." Test each object and chart the results. If working with older students, introduce the corresponding vocabulary words "transparent," "translucent," and "opaque."

  3. Try testing these objects for transparency, translucency, or opacity: glass, paper, plastic, cardboard, aluminum foil, tissue paper, water, mirrors, transparencies, kleenex, paper towels, etc.

  4. Discuss similarities among objects in each category -- e.g., shiny objects and mirrors

Assignment:

No Assignment for Day 2.

Day 3

Background:

Students conduct hands-on investigations into reflection, refraction, and absorption of light.

Motivation:

Prepare squares of paper in the colors of a rainbow. Ask students which is their favorite color. Have them take that color square and write their name on it. On a large piece of butcher paper, have students arrange the squares in the shape of a rainbow. If needed, fill in the remainder of the rainbow arc with additional blank squares.

Teaching & Practice:

  1. Review that light can be reflected, refracted or absorbed. Show students a prism. How does color come from the white light? Discuss possible solutions. Then ask students if the light entering the prism is reflected, refracted, or absorbed. Explain that when the light enters a prism, it is refracted. The prism separates light into colors. The band of colors made by the prism is called a spectrum. Deduce white light is made up of all colors. Link the colors of the spectrum to the colors used to make the rainbow graph.

  2. Have students Make a Prism to produce the colors of the spectrum.

  3. So why do things have color? Review that white light is made of all colors of the spectrum. Some objects absorb some colors of the spectrum and reflect other colors. When white light strikes a red object, mostly red light is reflected to our eyes. All of the other colors of the spectrum are absorbed.

  4. Make Giant Rainbow Bubbles or Rainbow Stew to experiment with the colors of the spectrum.

  5. Review properties of light.

Assignment:

No assignment for day 3.

Acceleration:

The following can be used by classes or individuals who wish to continue their study of the light energy.

Darken the room and use a flashlight on a wall. Make shadow animals.

Investigate your shadow. Choose a spot outside. Put a chalk mark on the ground so you stand in this same spot each time you go to investigate your shadow. Have a friend draw an outline around your shadow. Do this throughout the day at different times. You'll see your shadow changes as the position of the sun changes throughout the day.

The moon and the earth cast their own shadows. Find out how an eclipse and shadows are related.

All living things need light. Plants grow toward the light. If the light is all around the plants, the plants grow straight up. If the light comes from only one side, the plant will grow toward the light. Plant some grass seed in a small amount of soil in a small cup. Once the grass seed has started to grow, place the cup in a shoe box with a hole cut in the side of the box. Put the lid on the box so that the only light coming into the shoe box is through the side hole. Remember to water the grass, but to replace the lid on the box. After a week, notice how the grass is growing.

Remediation:

To remediate this lesson, review the questions posed in Topics for Discussion.

Assessment for this plan can take many forms. Teachers may apply the assessment tools they are most comfortable using. Here are some suggestions:

Anecdotal Records: Based on the interactive nature of the activities, anecdotal records could be used by teachers to record mastery of the objectives.

Test Stations: Teachers could also set up centers or stations around the room in order to test students mastery of the objectives. Students would then move around the room from center to center with a Performance Assessment Sheet to complete the various activities. You can use the Performance Assessment as an outline.

Activities