Light

Diagnostic assessment

Formative assessment

Summative assessment

Conceptual development progress map

Quiz

Formative assessment marking key

Summative assessment marking key

Diagnostic assessment

In the introductory activities for the Light module, there are a set of questions to think about that ask students to explain a number of scenarios regarding vision, transmission of light and colour. Students could discuss these questions in pairs and then report back to a whole-class discussion, enabling you to become aware of their existing understandings and misconceptions.

The research literature indicates that many students are not aware that incident and reflected light is necessary for vision and for seeing images in mirrors. The sun, for example, brightens objects so they can be seen. Research also indicates that some of the most common misconceptions students have about light are that:

• light goes around things, not just in straight lines
• colour is a property of objects rather than of reflected light
• light travels further at night than in the day
• distance travelled depends on size or brightness of the light source
• nocturnal animals (such as cats and owls) can see in total darkness.

There will be opportunities within the module to challenge these misconceptions. For example, students who believe that light goes around things, not just in straight lines, will have an opportunity to gather evidence about the transmission of light by looking at objects through a flexible tube and by lining up sheets of card with pin holes in them to view a light source. These types of experiences will help students recognise that light does travel in straight lines. Your skilful questioning will help them recognise differences between their initial beliefs and their observations and reach new understandings.

Formative assessment

In each part of the Light module there is a closing discussion in which students, with teacher guidance, develop answers to focus questions that capture the main concepts developed within the part. These discussions will allow you to monitor students' conceptual development. Students' summaries of these discussions and other work samples may be used to compile a portfolio of selected work samples that can provide useful formative information about their developing understandings. This information will help you select activities at the appropriate level to challenge your students, and, where appropriate, differentiate instruction within the class.

Items from the Light module quiz can be used individually at appropriate points through the Light module for formative assessment purposes. A formative assessment marking key is provided that links students' responses to the conceptual development progress map. This will give you information about students' levels of conceptual development (one to three stars) and help you select activities to challenge your students.

Summative assessment

The Light module quiz can be used as a traditional test for grading and reporting. A summative assessment marking key is provided for this purpose. The marking key can be used to identify the level at which students understand the concepts (high, medium or low) in terms of the stages of the conceptual development progress map or can be used for marking or grading. You may choose to modify the quiz to suit local curriculum outcomes.

Conceptual development progress map

Student understandings

Challenge rating	Reflection	Refraction	Dispersion into colours
Students recognise patterns in their direct observations of light being reflected, refracted and dispersed into colours.	Students understand: that light travels in a straight line as indicated by the formation of shadows that light bounces off smooth surfaces at the same angle that it strikes the surface that light can be focused in concave mirrors.	Students understand: that light bends when it travels from one transparent substance into a different one that light can be focused by convex lenses.	Students understand: that white light splits into colours when refracted a large amount, such as through prisms, or when shone at an angle into an aquarium of water.
Students show an understanding of the interaction of light with different media by representing reflection, refraction and dispersion as ray diagrams.	Students understand: that images are formed by reflection of light rays by plane, concave and convex mirrors and can represent this by ray diagrams.	Students understand: that images are formed by concave and convex lenses by refraction and can represent this by ray diagrams.	Students understand: that light rays are dispersed into colours when refracted by prisms and can represent this by ray diagrams.
Students demonstrate their understanding of the reflection, refraction and dispersion of light by applying concepts, models and laws to new situations.	Students understand: that images in mirrors are formed by processes that conform to the law of reflection, by light travelling in straight lines, and how images are inverted, in front of or behind mirrors, real or virtual.	Students understand: that refraction of light and formation of images by convex and concave lenses occurs by processes that conform to the law of refraction, light travelling in straight lines, refractive index, and how images are inverted, real or virtual.	Students understand: that dispersion is not easily explained by the particle model, but that it can be explained if light travel is modelled as waves having a wavelength and frequency that are seen by the eye as different colours.