Light is a complex concept that lends itself to misconceptions among teachers and students alike. These misconceptions may form as individuals attempt to make sense of the natural world, or as a result of the difference between scientific and everyday language. In other cases, misconceptions may actually form or be strengthened as a result of instruction.
Once formed, these misconceptions can be tenacious – persisting even in the face of discrepant events or careful instruction. Research has documented that students may be able to provide the “correct” answer in science class yet still not abandon their previously formed idea.
Even though targeting student misconceptions is difficult, teachers should be cognizant of their students’ beliefs before, during, and after instruction. Formative assessment can provide insight and guidance for planning lessons and meeting student needs.
In this article, we discuss some common misconceptions about light, heat, and the sun. We also provide tools for formative assessment and ideas for teaching the correct scientific concepts.
Misconceptions about light include the nature of light, the speed at which light travels, the behavior of light, image formation, and color. In keeping with our focus on the albedo effect, we focus on the reflection and absorption of light as well as the light from the sun.
A common misconception is that light can only be reflected from shiny surfaces (such as a mirror). Students may also believe that an object cannot absorb and reflect light – it must do one or the other. Of course, the correct concept is that all objects absorb and reflect light to different degrees. Our ability to see objects depends on the reflection of light!
Another related misconception is that the earth gets heat from the sun. The sun is actually too far from the earth to heat it directly. Instead, the light from the sun is reflected or absorbed by objects on earth. Absorbed light usually increases the energy in an object, causing the object to heat up.
PROBING FOR STUDENT UNDERSTANDING
What do your students think? A formative assessment probe from Volume 1 of Uncovering Student Ideas in Science helps you understand your students’ beliefs about the reflection of light. In the probe “Can It Reflect Light?” students are asked to decide which objects will reflect light and then share their thinking. The probe includes related research and suggestions for instruction and assessment.
In addition, we’ve followed the model used by Page Keeley and coauthors in the three volumes of Uncovering Student Ideas in Science (copyright 2005-2008 by NSTA Press) and created a similar probe to elicit students’ ideas about the energy from the sun.
What Comes from the Sun?
This formative assessment probe, modeled (with permission from NSTA Press) after those found in the three volumes of Uncovering Student Ideas in Science, is designed to assess student misconceptions about solar energy.
TEACHING THE SCIENCE
While identifying student misconceptions is fairly straightforward, creating conceptual change is not. Researchers recommend using a hands-on approach and providing adequate time and repeated activities to create the conditions necessary for conceptual change. However, it is important to understand that children may be quite resistant to change even when these suggestions are carefully followed. In some situations, researchers found that students developed two parallel explanations for scientific events: one for science class and one for the “real world!” Instead of becoming discouraged, teachers should be aware of the ideas that students bring with them to science and how these might influence instruction and learning.
It is also important to remember that some of the misconceptions regarding light may be appropriate for students’ current developmental level. Concepts such as reflection and absorption are difficult and cannot be easily visualized. While they may be introduced in the elementary grades, teachers should remember that students will develop an increasingly sophisticated understanding over the years and that complete mastery of these concepts is not to be expected at this point.
However, there are steps that elementary teachers can take to ensure that students begin to develop correct scientific concepts. Evaluating lesson plans, textbooks, and children’s literature for correct use of terminology and concepts is an important step in promoting scientific understanding.
An awareness of the role instruction can play in the formation of misconceptions is also important. For example, when you teach reflection of light, do you include shiny and dull objects in investigations? If students always talk about reflection in the context of mirrors, they are much more likely to believe that only shiny objects reflect light.
Lessons and activities that provide hands-on experiences or simulations of these concepts can help students develop a correct understanding. We’ve highlighted a few lessons below, and more can be found in “Hands-on Science and Literacy Activities About Solar Energy.” Content area reading, such as our Feature Story and titles from our Virtual Bookshelf, can extend and supplement the hands-on inquiry.
Continual formative assessment and dialogue about these topics will help you understand what your students are learning and how to best plan future instruction. Conversations and questioning techniques can also be used to guide and shape student understanding. For more information about asking effective questions, please refer to “Questioning Techniques: Research-Based Strategies for Teachers.”
LESSONS AND ACTIVITIES
Teach Engineering: Investigating Light (Grades 3-5)
In this lesson, students learn the five words that describe how light interacts with objects: “transparent,” “translucent,” “opaque,” “reflection” and “refraction.”
Teach Engineering: Light Scavengers (Grades 3-5)
In this activity, students examine various materials and investigate how they interact with light. Students use five vocabulary words (translucent, transparent, opaque, reflection and refraction) to describe how light interacts with the objects.
A Solar Energy Cycle (Grades 3-5)
This article, from the National Science Teachers Association journal Science and Children, describes a learning cycle (exploration, term introduction, and concept application) that was developed to help sixth-grade students understand that Earth gets visible light but not heat from the Sun.The article is free for NSTA members and can be purchased for $0.99 by nonmembers.
Teach Engineering: Let the Sun Shine! (Grade 3-5)
Students learn how the sun can be used for energy. They learn about passive solar heating, lighting and cooking, and active solar engineering technologies (such as photovoltaic arrays and concentrating mirrors) that generate electricity. Students investigate the thermal energy storage capacities of test materials. They learn about radiation and convection as they build a model solar water heater and determine how much it can heat water in a given amount of time. In another activity, students build and compare the performance of four solar cooker designs. In an associated literacy activity, students investigate how people live “off the grid” using solar power.
Teach Engineering: Cooking with the Sun (Grades 3-5)
Students learn about using renewable energy from the sun for heating and cooking as they build and compare the performance of four solar cooker designs. They explore the concepts of insulation, reflection, absorption, conduction and convection.
Give and Take (Grades 3-5)
Using a postcard made of temperature-sensitive liquid crystal material, students can monitor temperature changes. These changes show that dark materials absorb and reemit the energy contained in light more readily than light-colored materials.
National Science Education Standards
Assessing and targeting student misconceptions about light, heat, and the sun meets the Physical Science Content Standard and the Earth and Space Science Content Standard for grades K-4 and 5-8 of the National Science Education Standards.
Copyright October 2008 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.