Eyesight and Light: Examples of how difficult it is to change student's Misconceptions
Answer given when asked:
How does light help us see?
Fell into three categories:
Rays show that light travels from the source to an object and then to the person's eyes.
Rays show that light brightens the object.
Rays show that light brightens the object and anything else in its path.
Janet F. Eaton, Charles W. Anderson, and Edward L. Smith, found 3% of the students indicated on a pretest, category 1, an understanding that light shines on objects and is reflected to our eyes. After a text based lesson on light, 22% of the same students indicated on a posttest, that light shines on objects and is reflected to their eyes. The remainder of the students held to the misconception that we see because light shines on things and brightens them, category 2 & 3.
Reading the text did not challenge 78% of the students. Students in the study read passages that included information about light bouncing and reflecting from an object to their eyes. Passages such as: light travels in a straight line and light doesn't go through opaque objects did not change their misconceptions.
Students were also able to connect other ideas to their misconceptions without challenging their misconceptions. For example when students 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, color and what causes us to see color, what causes transparent; translucent; and opaque, and how lenses work.