Follow the beam: How light travels

Project Description

Light travels in straight lines. Light spreads out as it gets further away from the source.

Download the FREE Student Worksheet – Follow The Beam

Grades: 1 to 4
Duration: 1/2 Hour – 1 Hour

NGSS Connections PS4-B: Electromagnetic Radiation
  • Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light. (1-PS4-3)

Supplies: Activity sheets, 3 index cards with one hole punched in the same place in each, A set of Light Blox (one each red, green, blue), 3 binder clips, A plain piece of white paper, Mirror stand, A blank wall or screen

Featured Products
Light Blox Kit

Light Blox Kit

Step 1

Background

Students experience light as something that simply appears and then disappears. But actually, light travels – so fast that it’s difficult to experience. These two activities provide some experience with the fact that light travels – and it travels in straight lines that spread out over a distance.

With the first activity, students will use a Light Blox and 3 index cards to observe how light travels in straight lines.

With the second activity, students will use a Light Blox and a blank wall to observe that light spreads out as it travels over a distance.

Have students complete each activity (one at a time) Hold a classroom conversation after each one that incorporates students’ findings and covers the main discussion points!

Step 2

Discussion Points

Main Discussion Points – true of all light! • Light travels in a straight line • As light travels from the source (Light Blox) to the wall or paper, it “spreads” out and takes up more room. • As the light source (Light Blox) is moved further from the wall, it gets “bigger” and dimmer. • As the light source (Light Blox) is moved closer to the wall, it gets “smaller” and brighter.

Step 3

See how light travels in a straight line

Use binder clips to stand up your cards.

Remove the line cap from one Light Blox and shine it at your cards.

Arrange your index cards a few inches apart so that the light travels through all three holes.

How did you arrange your cards?

What happens when you move the center card just a little bit? Can the light “get around” the card and pass through the last hole? Why?

Step 4

See how light spreads as it travels

Turn on ONE Light Blox and shine the light at the wall. Move the Light Blox closer to the wall.

What happens to the light on the wall as it gets closer to the wall?

Turn on ONE Light Blox and shine the light at the wall. Move the Light Blox further away from the wall.

What happens to the light on the wall as it gets further away from the wall?

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