Nature of Science
When I first looked at the IB version of NOS I couldn’t see the difference between NOS and TOK. I still can’t, all of the NOS examples could easily be used in a TOK context, the difference is that NOS will be examined whereas the rest of TOK (if there is any TOK in physics that isn’t NOS) will not be. NOS is split into 5 sections
- What is science and what is scientific endeavour?
- The understanding of science
- The objectivity of science
- The human face of science
- Scientific literacy and the public understanding of science
Each section is split into several subsections; here I will try to give examples for each subsection. If you want a deeper understanding of what NOS is all about then you can refer to Berkley Universities website Understanding Science.
The assumption that universe has some external reality that we can make some sense of.
Newton’s universal law of gravity models the motion of planets and the formation of galaxies based on a simple mathematical relationship.
Some scientists work on theoretical models others develop new technologies.
In CERN some of the scientists are developing the theories to explain the results of collision experiments, others develop the technology required to accelerate the particles.
Scientists use a wide variety of methodologies
In class we sometimes derive mathematical relationships that are tested by experiment at other times we use experiments to find relationships.
To develop new theories scientists use creativity imagination along with well-structured thought processes.
To be creative one has to think in a new way, Einstein’s explanation of the attraction between masses being due to the curvature of space time was certainly creative thinking
Many discoveries have come from flashes of inspiration.
Roentgen’s discovery of X rays is said to be a chance discovery that was made when he noticed a cardboard covered fluorescent screen glowing whenever he switched on a cathode ray tube. The use of microwaves for cooking was discovered when a bar of chocolate melted in the pocket of World War II radar researcher Percy Spencer.
Scientists use reasoning, deductive logic, mathematics, analogies and generalisations to express their theories.
By applying Newton’s laws of motion to the collision between two balls we can deduce the principle of conservation of momentum.
Scientists don’t believe claims unless supported by evidence or good logical argument.
The Big Bang model of the Universe first proposed in 1927 was not accepted until the discovery of Cosmic background radiation in 1964.
Evidence can be obtained through our senses or sensors.
In astrophysics a lot of data has been obtained by using CCD technology.
Evidence is used to develop theories that can be used to make testable predictions.
Evidence of the interactions of known particles is used to develop theories that predict new particles and their interactions. Experiments are then performed to test the predictions leading to the discovery of the new particles and verification that they interact in the predicted way.
Models are developed to explain phenomena that we can’t see directly
The Kinetic model of a gas is used to explain the relationship between PV and T even though we can’t see the particles involved.
Experimental results are used to support claims.
Applying simple mechanics to a pendulum you can derive the equation . This can be verified by performing an experiment.
Computer models can be used to develop theories without direct experiment
Sophisticated computer models can be used to model the climate and make predictions about the future temperatures and sea levels.
Scientists operate in a community with common methods and processes.
Theories are comprehensive models
Atomic theory, kinetic theory, Einstein’s theory of relativity.
Laws are descriptive statements often in mathematical form but they do not explain phenomena.
Newton’s law of universal gravitation describes the relationship between mass and gravitational force but doesn't explain it.
A hypothesis is a statement that can be tested by experiment
The existence of the Higg’s Boson was hypothesised due to the mass of W and Z Boson. This hypothesis is now supported by evidence. The existence of the neutrino was hypothesised to explain the range of beta KE, this particle was later found to exist.
Scientific ideas are quantifiable relationships open to falsification.
The second law of thermodynamics implies that the thermal energy in a block of wood cannot cause it to jump into the air, if this was observed to happen the law would not be true.
Occam’s Razor (Keep it simple)
The existence of all hadrons could be explained in terms of many more than 6 quarks but the simplest solution is best.
Correlations are important in science
Most of the practical work we do in physics is to find relationships between quantities; these relationships are tested by drawing graphs. One famous example of a correlation is the CMB which was found to be extremely close to the theoretical black body curve.
Controlling other factors is important
The gas laws are examples of laws that only apply when other quantities are kept constant. The Pressure of a fixed mass of gas is inversely proportional to its volume provided temperature remains constant.
Scientists analyse data looking for relationships
Kepler found out that the square of the time period of planetary orbits was proportional to the cube of their radius by studying data.
Repeated measurement reduces uncertainty
This is why we ask students to repeat measurements in their practical work although the number of repeats they often use is not really enough.
Scientists are aware of errors and uncertainties
In all practical work students are asked to consider uncertainties and draw error bars etc. Early experiments performed to support Einstein’s theory of relativity had errors that were as big as the measurements.
Scientists should avoid the temptation to select data that fits expectations
When carrying out practicals with known outcomes students are often tempted to leave out data that doesn’t fit their expectations. CMB was thought to be caused by pigeons when it was first discovered.
Levels of confidence are used to express how certain scientists are of their predictions.
Digital devices have enabled collection of a lot of data in a short time.
During the early days of particle physics the paths of particles photographed in cloud chambers were traced by hand, now all the data is processed directly by computer.
Large amounts of data processed digitally are difficult to check.
Science is collaborative
Different people working on the same problem from different angles can result in a clearer understanding, CERN even employ artists and musicians to add to the creative influence.The group 4 project is a the time when this point can be emphasised
Teamwork is important
Sharing data on the internet can increase the chance of finding a solution.
Peer review increases the validity of scientific results
This is not something that really comes across in the course and apparently wasn't a big thing for early scientists whose work we study.
Research in science often has ethical implications
The obvious example here is the discovery of nuclear fission leading to the atom bomb, but digital technology and developments in transport have also changed the way we live.
Integrity and honesty is important
On a small scale it is important that students do not fake data in their own experiments.
The source of funding can sometimes change the outcome.
In 2010 25% of the public spending in the UK on research and development was for military purposes (link).
Science can improve our lives but sometimes it doesn’t
Nuclear fission has resulted in the development of nuclear power (good?) and the atom bomb (bad).
Sometimes an understanding of scientific principles is required when making political decisions
There are claims that the experiments in CERN can create black holes capable of swallowing the Earth. A lack of understanding could lead people to believe these claims resulting in a withdrawal of funding.
It is the responsibility of scientists to educate the general population so they can make considered decisions.
People should be aware of faulty reasoning
Just because a physicist understands how fibre optic communication works it doesn’t mean they are an authority on the social implications of the internet (false authority).
If you expect the distance travelled by a ball to be proportional to time you might ignore a result that clearly didn’t fit the pattern of increasing distance with increasing time (confirmation bias).
If the extension of a rubber band divided by the weight hanging on it is constant for 3 different weights it does not mean that the rubber band obeys Hooke’s law (hasty generalisation).
Pseudoscience is not science
Theories on the workings of UFO’s, how cars can be powered by water or the way electromagnetic fields generate crop circles sound scientific but they aren’t science.
Scientists should be wary of using terms that mean something different in science to what they mean in general usage.
An error is not a mistake, a fluid is a liquid or a gas, power is nothing to do with politics, the police are not a force and impulse is not impulsive.
Science has achieved a great deal but there are many unanswered questions.
We don’t deal with many of these in the course, all of our questions have answers.
If NOS is to be tested on the written exams, what sort of questions will there be? This will be made much clearer when the TSM comes out but for now we can only guess. The specimen papers give some clues but it's difficult to find the relevant questions. All of the questions in a physics exam are related to the nature of science since in one way or another but they aren't testing knowledge of NOS. The closest I could find on paper 1 to a question testing knowledge of NOS was one about wave particle duality:
"Why is wave particle duality used in describing the properties of light?"
I don't think a student would need to know anything about NOS to answer the question, a knowledge of physics would be enough.
On paper 2 there is the question:
"Outline how scientists continue to attempt to resolve the climate change debate".
This question requires some understanding of how scientists work, to resolve the debate scientists need more than just a persuasive argument they need data and this data comes from measurement and computer simulation.
On paper 3 there is a question about the Carnot cycle:
"The Carnot cycle applies to a theoretical engine. Discuss how the understanding of this theoretical engine could help engineers design more efficient machines."
This one deals with the relationship between science and technology, even though the Carnot cycle is not possible it sets a limit for real engines.
Also on paper 3 there is a question about the use of telescopes:
Telescopes available today include, in addition to optical telescopes, infrared, radio, ultraviolet and X-ray telescopes. Outline how the introduction of these telescopes has changed our view of the universe.
Advances in technology have led to the development of telescopes that are able to gather data from different regions of the EM spectrum allowing astrophysicists to develop much improved models of the universe. This is, I think, a good example of an NOS question. If you didn't know that the question was about NOS it would be difficult to answer.
So, the type of question are physics questions that should be answered from an NOS perspective rather than NOS questions answered from a physics perspective. Knowing the different areas of NOS will help a student to understand what the question is asking.
The website mentioned earlier has a very useful flow chart showing the way science works from Inspiration > observation > experiment > etc. I'll stop writing this list of stages because the point is that it's not a linear process it's a whole complicated network of branching stages as represented by the flow chart. Any scientific can be tracked around the flow chart but there are many different paths, I thought it might be fun to make the chart in prezi so I can take show the paths taken by different scientists whilst developing their theories. Here it is: