Initial Planning Reflection for - An Activity Sequence on Light


Light is a form of energy that travels in a straight line until it strikes or interacts with an object. Interactions can cause light to be reflected such as with a mirror, refracted by objects such as lens, and reflected or absorbed by any object it strikes such as a block.

Possible Related Concepts

  • Light interacts with matter by transmission (including refraction), absorption, or scattering (including reflection).
  • To see an object, light is emitted by the object or reflected from it and enters the eye.
  • Light is reflected at an angle proportional to the angle it strikes an object.
  • Light is refracted at an angle related to the angle that it enters or leaves a medium and the density of the mediums.
  • Color is a property of light.
  • White light has all colors.
  • Black is the absence of light and/or color.
  • White light can be refracted to view a spectrum.
  • Light is a form of energy that can be transfered or changed to other forms of energy.

What instructional theory and learning theory should be used to begin to facilitate student learning for these ideas?

I would want to begin with exploration so the students will learn through their own actions and reactions in a new situation.  If they explore new materials and new ideas with minimal guidance or expectation of specific accomplishments, the new experience should raise questions they cannot answer with their present ideas and patterns of reasoning.  Having made an effort that most likely will not be completely successful, they should be motivated to ask questions and begin to look for ideas that will lead them to self-regulation. Meanwhile, I will have collected enough assessment data to begin to know what they understand and where I might begin to facilitate their learning in the second phase: invention.

What activities could be used for the first activity with students?

Activities Review a resource file or a list of possible activities that would fit the concepts and generalization.

List of possible activities

1.  Listing the assumption of light as a particle that travels in a straight line?

2.  Doing an activity in which students could assemble light sources, mirrors, plastic blocks, colored filters, and glasses of water to observe how it interacts with these objects?

3.  Asking students what everyday experiences with light they have and describe the properties of light that those observations indicate.

4.  Describing the transfer of electromagnetic radiation at various frequencies, and then focusing on the visible spectrum of light?

5.  Doing an activity as in two, but making certain that your students could work with a laser pointer as source with a good projection of a line?

6.  Doing an activity where students are assigned to measure accurately the focal lengths of plane, convergent, and divergent mirrors, and lenses (diagram their results).

Making a decision

Review what resources are needed for each activity and the preparation of students needed for each activity. Eliminate activities that wouldn't fit the availability of resources and the readiness of students. Then think about how each would or would not be good to use as the first activity.choice.  When you have done that, compare the ideas below with yours, and if possible, with those of others.

Reflect on the positives and negatives for each and make a decision as to what you believe might be the best before continuing.

  Compare your ideas with the following:

 1.  This procedure is frequently used because of its conciseness but it is likely to be difficult for students, especially students using concrete reasoning patterns, to assimilate.  They do not know the basis of the assumptions and therefore cannot evaluate when and how the new ideas are to be used.

2.  We would prefer an approach of this kind, where the student has a great deal of freedom to use his or her own judgment and try out his or her own ideas as he or she gains practical experience with the objects he will study theoretically later.  See also five.

3.  In the absence of exploratory materials, this approach can be attempted to connect any new ideas about how light interacts with objects with the students previous experience; demonstrations with student participation would help.

4. This theoretical approach is inappropriate as one of the activities, because it highlights the wave nature of the light which is not helpful for constructing a model to describe lights interactions with these objects.

5. Since light “rays” play an important part in creating a model of how light interacts, it should be very helpful. An ordinary comb with coarse teeth can be used very effectively to make a bundle of light “rays” whose behavior can be followed.

6. This type of activity prevents the student from asking his or her own questions and satisfying his own curiosity.  The concept of refraction and reflection needs to be operationally defined and understood before this lab can be worthwhile.  At a later time in 7-8 grade middle school, it might be quite appropriate, though a more open approach would be preferred.

The preferred approach in two or five is an example of the “exploration” phase in the learning cycle which is recommend for the planning at the beginning of a learning sequence.  The entire learning cycle consists of three phases: exploration, invention, and discovery.  During exploration students learn through their own more or less spontaneous reactions to a new situation.  In this phase, they explore new materials or ideas with minimal guidance or expectation of specific achievements.  Their patterns of reasoning may be inadequate to cope with the new data, and they may begin self-regulation. During this phase of the learning sequence the teacher is collecting assessment information to facilitate students' learning in the invention phase of the learning cycle.

During the “invention” phase, it is appropriate to define a new concept, introduce a new principle, or explain a new kind of application to expand the students’ knowledge, skills, or reasoning.  This step should always follow exploration and relate to the exploration activities.  It will assist in students’ self-regulation.  In the example above, for instance, alternative one represents a possible “invention” phase, perhaps introduced via activity three as an intermediate step to relate exploration and invention.  Encourage all students in the invention to “invent” part or all of a new concept (idea) for themselves, before presenting it to the class.  The invention of some concepts will require several activities to develop students’ understanding.

Multiple activities sequenced in the invention phase of the learning cycle, allows students to find the limits of the concepts or skills he or she has conceptualized (learned) earlier.  This provides additional time and experiences for self-regulation.  It also gives opportunities to introduce the new concept repeatedly to help students whose conceptual re-organization proceeds more slowly, or who did not adequately construct accurate representations from their observations in the earlier experiences.  Individual conferences with these students are helpful to identify their difficulties, By reaquainting them with observable data that is contrary to their explanations, change in their understanding is possible. Without previous experiences to relate to the new ideas students will likely continue with their alternative nonscientific or less accurate understandings.

Generalization of concepts is encouraged in the third phase, expansion, where concepts are combined to create generalizations or experienced in unique or unusual ways. Which provides a measure of the students' depth and breadth of understanding.

Dr. Robert Sweetland's Notes ©