Year 6 Science Light – Block 6L – Crime Lab Investigation

Session 3:Up periscope
Science curriculum area: Light / i) recognise that light appears to travel in straight lines
ii) use the idea that light travels in straight lines to explain that objects are seen because they give out or reflect light into the eye
iii) explain that we see things because light travels from light sources to our eyes or from light sources to objects and then to our eyes
Working Scientifically (UKS2) / i) planning different types of scientific enquiries to answer questions, including recognising and controlling variables where necessary
ii) taking measurements, using a range of scientific equipment, with increasing accuracy and precision, taking repeat readings when appropriate
iii) recording data and results of increasing complexity using scientific diagrams and labels, classification keys, tables, scatter graphs, bar and line graphs
iv) using test results to make predictions to set up further comparative and fair tests
v) reporting and presenting findings from enquiries, including conclusions, causal relationships and explanations of and degree of trust in results, in oral and written forms such as displays and other presentations
Teaching Objectives /
  • Describe the movement of light beams off of reflective surfaces
  • Plan and carry out an investigation into the reflectiveness of given materials
  • Record results in the form of a graph and note patterns
  • Suggest how to investigate further their findings

Key Vocabulary:light, light source, names of light sources, e.g. torch, dark/darkness, reflect, reflective, mirror, shadow, block, absorb, direct/ direction, transparent, opaque, translucent, straight, rainbow.
ResourcesShiny metal, mirrors, shiny coloured Perspex, retro reflectors (all flat), torches, sticky-notes, rulers, light meter / Weblinks Reflective materials; - BBC Bitesize: How we see things game; Make your own periscope or kaleidoscope.
Whole Class:It has been noted that the thief knew when corridors were clear and that the classroom targeted was empty. A small box was spotted on CCTV at each corner prior to the thief arriving - the Crime Lab believes that this was a periscope. Each of the remaining suspects has been found with a periscope, but each used different materials toreflect the light. These materials have been recovered (as well as each suspect's explanation for having periscopes) and it is the chn's job to work out which of themcould not have worked. But first chn need to understand how light beams can be redirected through reflection to enable a periscope to work. Play the BBC online game as a class and then in small gps give chn mirrors and torches. Ensure the room is dark and get chn to ‘play’ with the beams of light and try to work out how to position a series of mirrors to redirect the light beam to a given target on the table (just like in the BBC game). See if they can draw the lines of the beam on a large piece of paper on the table (under the mirrors) and draw a ‘normal’ direct reflection angle at 90 degrees to the mirror line. What do chn notice about the angle of the light beam in and out (it is the same). Challenge chn to create a ‘human’ periscope to demonstrate how the light beams reflect off the surfaces to reach the viewer’s eye. Once you are confident that the chn understand the nature of reflecting angles off a highly reflective surface, explain that the chn are now ready for their Crime Lab work. Explain that once the investigation is done, chn will need to record their method, findings and recommendations for the court case. Ask chn to remind you what key ‘ingredients’ they need to consider and record (a specific enquiry question, variables, equipment, method, observations, limitations, possible further lines of enquiry, scientific explanations, and patterns and conclusions).
Activities:Chn to work in mixed ability gps.Ensure each gp meets to discuss each flatreflective surface (retro reflector, mirror, metal, Perspex) deciding which will work and which won’t,based on their expectation of how the light will reflect. Once they have suggested any that they think won't work, give chn the periscope instructions (see link) and get them to create their own.Chn will then need to record their method and findings - note that this is a qualitative test rather than a quantitative test so how will chn ensure they are comparing the materials accurately (more than one opinion/the person ‘viewing’ and testing doesn’t know what they are looking at, so only if it is distinguishable does it work, etc) .Challenge chn to suggest an alternative way of measuring which material reflected the most that would give us a quantitative result (clue - use a light meter). Get chn to draw a bar graph to show the results. Get chn to make decisions about the properties of the materials that they think make a highly reflective surface (shiny and smooth). How could they test this further? Whose periscope wouldn’t have worked? (Nouri Kashani)
Plenary / Get chn to share their findings and identify the next suspect to go. Why do they think the rougher the surface the less reflective (light shot back in different directions - see diag), or the duller the surface the less reflective - more absorbed.Get chn to set out how they could investigate this further. Watch video on use of reflective materials.
Outcomes / Children will
  • Demonstrate and describe the movement of light off mirrors
  • Plan and carry out an investigation into the reflectiveness of given materials
  • Record results in graphic form and identify patterns
  • Suggest further investigations for their findings

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