The method and the results are on the how light travels lab. Do the analysis yourself first, then check the answers below.
Quick answer: Light is a form of energy that travels in straight lines called rays. These answers go with the grade 6 science lab on how light travels: the graph, the calculations, the uncertainties and the conclusion explained, for all 7 analysis questions.
The model answers use the sample readings in the results table. Your own readings will differ, but the order of the materials and their classification should agree, and the cards should block the light when misaligned.
Clear plastic is transparent. Bubble wrap and tracing paper are translucent. Cardboard and aluminium foil are opaque.
Question 4 Ranking
Clear plastic (112), bubble wrap (90), tracing paper (65), then cardboard and foil tied at 0 lux.
Question 5 Fair test
The distance from torch to sample, the distance from sample to meter, and the same torch and room light. If any changed, the readings would differ for reasons other than the material, so the test would not be fair.
Question 6 Straight line test
You saw the torch only when the three holes were in line. Moving the middle card hid the torch. This shows that light travels in straight lines.
Question 7 Improving accuracy
Work in a darker room so stray light does not add to the meter reading, and take more repeats. A fixed holder gives the same distances each time. Any two sensible improvements are accepted.
