The Nature of Chemistry
  • Home
  • Recent news
  • NOC
    • The scientific method
    • Observation and inference
    • Evidence, modelling and prediction
    • Theories and paradigm shifts
    • Cause and effect
    • Accuracy, validity and reliability
    • Reason and imagination
    • Bias and the role of humans in science
    • Communication of science
    • Contrasting with other areas of knowledge
    • (IB TOK outline)
  • Topics
    • Stoichiometry
    • Atomic structure
    • Periodicity
    • Chemical bonding and structure
    • Energetics
    • Chemical kinetics
    • Equilibrium
    • Acids and bases
    • Redox processes
    • Organic chemistry
    • Measurement and data processing
  • IB Options
    • A - Materials
    • B - Biochemistry
    • C - Energy
    • D - Medicinal chemistry
  • People
  • Answers
    • NOC answers
    • Topics answers

Evidence, modelling and prediction

Suggested answers can be found at the bottom of the NOC ANSWERS​ page.

Activity 1 - Mystery box

Conceptual understanding: We can propose models of things we can't see using experimentation and observation.
Picture
Time: 30 min.
​
Task: Prepare a mystery box by adding a number of objects inside and sealing it. Students must attempt to draw a model of what is inside the box with an explanation of their thinking. Questions for students:
  1. ​What do they think is in the box? Why?
  2. Which ways of knowing did they use?
  3. Is 'seeing' the best way of knowing in this exercise?
  4. Without opening the box, but with an infinite budget, how could they improve the accuracy of their model?
​Extension: Do we need to see inside the box to 'know' what's in there? Can you think of any contexts where other ways of knowing are more important?

Activity 2 - Modelling the atom

Conceptual understanding: Models of the submicroscopic world can be used to explain macroscopic properties of matter
Time​: 20 min
Task​: Depending on your level of study, you may have seen some or all of these models of the atom (left). Models are constructed by chemists to help try to explain the behaviour of matter that we can see. There is no such thing as a right or wrong model - just a more or less useful one.

Consider the following questions:
Picture
1a. As a start point, it may be useful to try and recall what the features of these different models are. For example, model a represents a single, solid piece of matter. What are the other models composed of?
1b. Each of these models is useful in some way as they were each created as a possible way to explain an observation or inference. Can you suggest which models might be useful for the observations/inferences below and why? It might also be useful to consider which models would not be useful in each case. More than one model might be useful for each.
Observation 1: When I push against a wooden door, my hand does not go through the wood.
Observation 2​: Negatively charged particles can move independently in a cathode ray.
Picture
Inference 1: An atom is made mostly of empty space.
Inference 2: An atomic emission spectrum suggests that electrons can move between levels of differing energy.
Picture

Activity 3 - Modelling mass spectrometry

Conceptual understanding: Macroscopic modelling might help with submicroscopic understanding.
Picture
​Time: 5 min.
Task: Imagine that you roll each of these iron balls past a magnet at the same velocity.
  1. Sketch the relative paths that each would take as it passes the magnet.
  2. Can you explain your sketches?
  3. How would the lines change if a stronger magnet was used?
  4. What about a weaker magnet?
  5. How might this relate to positive ions passing through a magnetic field in a mass spectrometer?
  6. Can you suggest any weaknesses of this model?

Activity 4 - Modelling a pandemic

Picture
Conceptual understanding: Modelling has strengths and weaknesses
Time: 10 min.
Task: 
  • Investigate the different factors that impact the spread of a virus using this simulation. Identify which factors are most important to control the speed of spread of a virus.
  • What might a scientist need to know to set up a simulation such as this one?
  • Can a simulation be 100% accurate? What are the limitations of models and simulations in science?
Proudly powered by Weebly
  • Home
  • Recent news
  • NOC
    • The scientific method
    • Observation and inference
    • Evidence, modelling and prediction
    • Theories and paradigm shifts
    • Cause and effect
    • Accuracy, validity and reliability
    • Reason and imagination
    • Bias and the role of humans in science
    • Communication of science
    • Contrasting with other areas of knowledge
    • (IB TOK outline)
  • Topics
    • Stoichiometry
    • Atomic structure
    • Periodicity
    • Chemical bonding and structure
    • Energetics
    • Chemical kinetics
    • Equilibrium
    • Acids and bases
    • Redox processes
    • Organic chemistry
    • Measurement and data processing
  • IB Options
    • A - Materials
    • B - Biochemistry
    • C - Energy
    • D - Medicinal chemistry
  • People
  • Answers
    • NOC answers
    • Topics answers