This is taken form part of a seminar given as part of the APECS Project (Able Pupils Experiencing Challenging Science): Challenging pupils with scientific explanations, where the context is described.
As part of a sequence of activities on explanations with Y9 (13-14 year olds in the English School System), the students were asked
and if they could
When asked at the start of the session ‘what do you think makes a ‘good’ scientific explanation?’ there was again a wide range of answers - some quite eloquent,
“A logical, clear explanation of why something is like it is or why it happened. Using what you know to help you explain.”
Ten of the responses made reference to the explanation being based on “evidence to support it” (even “conclusive evidence”) or proof,
“You need to use facts and evidence for your explanation and see how it all links to prove your scientific explanation”
Nine of the students made references to the effect that the explanation should include reasons or explain why.
“one that is simple, but explains reasons and details”
There were also nine references to the importance of clarity.
“One that clearly explains the problem at hand, explaining each possible outcome.”
Eight of the students referred to simplicity – not “too complicated”, “as simple language as possible” - or being ‘to the point’.
“something that is clear and straight to the point, it is better if you can make it as short as possible, but should still try and use all the main points, or what you have to know.”
Seven of the students thought that good scientific explanations should be concise.
“Concise, clear and simple explanations including diagrams and reasons for results.”
Six of the students referred to the need for detail, or for the explanations to be in-depth.
“Detailed evidence and reference from text”
Five of the students thought that good scientific explanations should be comprehensive
“An explanation is good when it gives a complete overview as well as detail on every specific aspect.”
Four students emphasised the need for the explanation to be capable of being understood.
“One that is easy to understand and use, and one that gives information needed and no more”
Three of the students thought that the explanation should show patterns of trends in the data,
“A good clear answer that explains why things happen like they do, and shows any patterns or trends in their answers.”
Three thought it should include reference to when (the conditions – “what you did to make it happen”) under which it would apply.
“Something that takes into consideration the conditions from which you obtained your info to make an explanation, clear & concise, not necessarily the obvious result, conclusive.”
When asked if they could ‘give an example of a good scientific explanation?’ twelve of the group did not make a suggestion. Newton/gravity was mentioned four times, and Einstein/relativity twice. The other suggestions were photosynthesis; friction; adaptation to habitat; evaporation; why the earth orbits the Sun; the properties of light; unbalanced forces; rate of reaction being proportional to surface area; acid reacting with marble and the ability to rearrange the defining equation for pressure!
“If you’re using equations, e.g., for pressure (pressure = force/area) this can be changed to: (triangle with F at apex over A×P) this can be used when any of the factors aren’t known. Making it more useful.”
Some of these responses did not give sufficient information to be certain what the actual ‘explanation’ being considered was: so by itself “plants photosynthesis to make food” cannot really be considered an explanation, and “why we go round the sun” provides an invitation for an explanation rather than the explanation itself. A Newton supporter thought that “Sir Isaac Newton did a good job on explaining gravity”, whereas an Einstein fan proposed E=mc2 as his example of a good scientific explanation on the basis that “it makes sense, it works, it can be understood, it explains how”. If this is an informed and measured judgement then this particular student is surely among the ‘gifted and talented’! The ‘explanation’ of ‘what light does and how’ could be considered more as a summary of properties,
“light travels in straight lines, it goes at a speed of…per minute. Light is white but can be split into many colours. Light can be bent or changed in different ways, there are…Light cannot travel through opaque objects etc.” (…in original!)
However some of the suggestions could be considered to be close to genuine scientific explanations,
“Water evaporates because heat causes the water molecules to turn into a gas water vapour, which can be seen as steam”
“More CO2 is produced on a piece of marble with a larger surface area (in hydrochloric acid) than on a piece with a smaller surface area because there is more of it exposed for the acid to dissolve therefore causing more CO2 to be produced.”
Other activities concerned suggesting explanations, suggesting what they would like explained, sequencing explanations, and evaluating explanations (see Challenging pupils with scientific explanations).
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Dr Keith S Taber kst24@cam.ac.uk
University of Cambridge Faculty of Education
© Keith S Taber, 2003/2013