- Test hypotheses through observation,
- Despite being experts can still have flaws in their thinking,
- Scrutinise knowledge claims,
- Are both open-minded and skeptical about claims,
- Question what is held to be true,
- Can view scientific claims differently.
It should be stressed to students that thinking of scientific claims as true and false is overly simplistic since most scientific claims fall along a true-false continuum. The truth tests often referred to in TOK are a simple (if some what problematic) tool for evaluating the truth of a claim.
- Coherence test – The claim is more likely to be true if it does not contradict what is already known.
- Correspondence test – The claim is more likely to be true if good evidence can be found to support it.
- Pragmatic test – The claim is more likely to be true if it can be observed or tested by experiment
There are three parts to this activity
- Setting the scene
- Providing students with a question and some assertions to focus their thinking
- A guided task that involves students using a variety of texts to examine the focus question and assertions.
The students are divided into groups so a wider range of different texts can be examined. Seven texts / groups have been provided for, although the number of groups will depend on the size of the class. Teachers can choose the most appropriate texts for their class.
Setting the Scene
Students watch the BBC news report on the discovery of particles traveling faster than the speed of light https://www.youtube.com/watch?v=WFzM16w9UOM or listen to this podcast http://www.npr.org/2011/11/18/142518953/scientists-claim-neutrinos-are-faster-than-light
To what extent do you believe the claim that neutrinos can travel faster than the speed of light?
(Extent means consider the merits of the claim. Ways in which you can and cannot support the claim.)
In thinking about the question the student’s consider the following assertions
- Identifying error is an important part of the process of verifying scientific claims.
- Scientists are more likely to trust claims when all possible sources of experimental error have been eliminated.
- Scientific claims are more likely to be accepted if other scientists can verify them.
- Physicists know there is a universal speed for everything.
- The process of peer review requires scientists to present the claims made through research to other experts in the field for critique.
Thinking (15-20 minutes)
- Each group uses the text they have been assigned to consider their response to the focus question. All opinions should be supported with evidence from the text.
Sharing (approximately 20 minutes)
- Each group has three minutes to share their opinions on the focus question with the rest of the class.
Reflection (10 minutes)
- Students consider where they stand. Have the students line up on a continuum. At one end of the continuum is Neutrinos can’t travel faster than the speed of light. Einstein was correct and at the other end. Neutrinos can travel faster than the speed of light. Einstein got it wrong. Selected students can share with the class the reason for their placement.
Debrief (5 minute)
Group 1. Neutrinos:
Group 2. Positrons
Group 3. The Quarks
- Resource: http://www.nature.com/news/neutrino-experiment-replicates-faster-than-light-finding-1.9393
Group 4. Leptons
- Resource: http://cosmiclog.nbcnews.com/_news/2012/02/22/10479879-flaw-found-in-faster-than-light-setup
Group 5. Force carriers
- Resource: Physicists Janet Conrad http://www.pbs.org/wgbh/nova/einstein/expe-conrad.html and Alan Guth http://www.pbs.org/wgbh/nova/einstein/expe-guth.html talking about the equation E=mc2
Group 6. Neutrons
Group 7. Higgs Bosons
- Resources: The official Opera website http://operaweb.lngs.infn.it/ and the Research paper produced for peer review http://arxiv.org/abs/1109.4897
Student voices. What were they thinking?
Replication of this type of experiment by independent groups in necessary to ensure that there is no confirmation bias, and that errors haven’t been made by the first research team. Science depends on Poppers Theory of falsability so if other teams find that neutrinos are not travelling this fast, then we would have to discard the theory. This is because it is easier to prove falsibility.
We cannot fully believe that the claim is completely reliable considering the fact that we have not yet looked at other information, since all we have is the peer review; We however can take into account the fact that before publishing, the scientists did 15,223 repetitions of experiment to test data, simply the fact that so many re-tests occurred allow us to suggest that the results are quite reliable. As well as this, we can see that 258,000 professionals have been visiting the site and thus looking for more information on this topic. At the very least they are searching for potential issues and have tried to deal with those, suggesting validity. However, at the same time, the fact that they might have repeated the mistakes in the repetition process makes us once again wonder whether or not the theory is valid.
So many things could have gone wrong; they checked for ONE of these things. There are many underlying systematic errors. There is no way to know if they are making more errors and they don’t even know which error they are looking for. This discovery could revolutionise what people think about science, but up to now there is not enough evidence to back up their claim.
Scientists have an “emotional” connection to the theory of relativity, all scientific discoveries based on Einstein’s theory of relativity would be incorrect. This is why people are reluctant to let go of what they think and believe.
Maybe they’re wrong? It’s easier to disprove than to prove, it doesn’t matter how many examples you prove, as long as there is that one example that disproves it, the claim can be wrong. Also, science is constantly evolving, so it’s possible that this is another stepping stone in the journey of science. Then again, what is the speed of light? How can we measure the speed of light and how true can the measurement? We say, keep testing, try again or change aspects of the experiment and re-run it.
OPERA’s claim was that the particles could travel faster than the speed of light. In order to say this claim to be true, it needs “extraordinary” evidence. To support the claim, the evidence must be tested repeatedly and error must be minimized. The GPS system and the proton pulses must change in order to minimize error.
Not only does the experimental component have to be replicated, the theoretical component must be proven mathematically. The theoretical component must prove that Einstein was not right and that the new evidence is correct.
The implication of saying the Theory of Relativity is wrong would call all of Einstein’s work into critique. If one of his theories were wrong, all of his other work would be questioned.
While scientists want new discoveries, it is still hard to let go of what we think we know.
|Prior knowledge||✔||Nature of subatomic particles|
|Chemistry syllabus & cross curricular links (first exams 2016)||✔||Topic 2: The nuclear atomC.3 Nuclear Fusion and Fission|
|Learner Profile attributes||✔||Thinkers, Knowledgeable, Reflective|
|Approaches to Learning||✔||Thinking skills|
|Nature of Science||✔||What is a scientific endeavorThe understanding of scienceThe objectivity of scienceThe human face of scienceScientific literacy and the public understanding of science|
|International mindedness||✔||Science is an international endeavor|
|TOK||✔||How knowledge is constructed and evaluated.|