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Science_Lab_Yellow / Lesson 2: Light Travels

Light Travels


What will we be learning today?


  • In this lesson, we are going to learn all about how does light travel.

  • How Does Light Travel?


    Take a look at the drawings below. Which path do you think shows how light travels to your eyes?


    This student is trying to see what kind of path light takes as it travels from one point to another.


    Light casting a shadow suggests that light travels in straight lines.

    In the illustration above, a light bulb casts the shadow of a microscope on a wall. If we draw a straight line from the light bulb to any part of the microscope, we can follow the line directly to that part of the microscope's shadow. This might suggest that light always travels in straight lines. However, this is true only when a substance like air or water remains the same along the whole pathway of light.

    In fact, light usually changes direction when it passes from one substance into another. Otherwise, as long as light travels through air or water, it follows a straight line.


    This model uses water waves to show how light waves bend as they travel past very thin objects or pass through very tiny holes.

    Actually, light travels as a series of waves. These waves can be disturbed or bent when they travel past the edge of a thin object or flow through a very narrow opening


    When free of snags, however, light waves move as shown below. If we could follow a point on a light wave as it ripples outward from its source, we would trace a straight line. This beam of light is called a light ray.

    Each small section of a light wave follows a straight path, creating a ray of light.

    When the flashlight is on, electric current from the batteries flows through the metal strip and lights the bulb.


     Let's Review What We Learned Today!


  • Now complete your worksheet!