Light and eyesight

Overview

Describes examples learners use to explain light and being able to see. Includes misconceptions learners use to explain sight and research to support how difficult it is for learners to change their thinking.

When learners are asked.
How does light help us see?

Their answers include an accurate discription: Light travels from a source to an object and then to a person's eyes. And other categories:

  1. Light brightens all objects and anything else in its path.
  2. Light brightens all objects and anything else in its path.
  3. The eye sends out something (light, feelers, thoughts) to probe where we look to see.

Janet Eaton, Charles Anderson, and Edward Smith found three categories among the fifth graders they studied and how their understandings changed or didn't change after reading about eye sight.

Categories fifth graders gave to explain light and sight

Category One

Light travels from a source to an object and then to a person's eyes.

The diagram shows rays of light traveling from the Sun, source, to an object, tree, and then to the person's eyes.

Light reflects to eye

 

Category Two

Light brightens objects.

The diagram shows rays of light traveling from the Sun, source, and brightening an object, tree.

 

Category Three

Light brightens all objects and anything else in its path.

The diagram shows rays of light traveling from the Sun, source, and brightening all objects, tree, puddle, ...

 

Findings:

When learners were asked: How does light help us see? they found:

Reading the text did not challenge 78% of the learners enough to change their conceptions.

They read passages that included information about light bouncing and reflecting from an object to their eyes. Information such as: light travels in a straight line and light doesn't go through opaque objects did not change their misconceptions.

Learners were able to connect these ideas to their misconceptions without challenging their understandings. For example, when they learned the parts of the eye and how the eye works. They could have memorized that light enters the eye and traced it to the brain. However, this probably did not cause them to ask, how the light got to the eye.

Consequently understanding how light reflects is essential for understanding sight and how the eye works, how we percieve color and what causes us to see color, what causes transparent; translucent; and opaque, and how lenses work.

 

Source: Students' Misconceptions Interfere with Learning: Case studies of fifth-grade students. Janet F. Eaton, Charles W. Anderson, and Edward L. Smith

Related knowledge bases

 

Dr. Robert Sweetland's notes
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