Your first physics notebook
A notebook is a place to make one question reproducible: define inputs, run a calculation, inspect the output, and state what it means.
Think like a programmer
Model checklist
- Inputs
- Mass in kilograms and height in metres.
- State
- The chosen constants for this experiment.
- Rule
- Multiply mass, gravity, and height.
- Output
- Gravitational potential energy in joules.
- Check
- Zero height must produce zero energy.
A tiny physics notebook
potentialEnergy = mass × 9.81 × height = 98.10 J
Try this experiment
Prediction: Doubling mass doubles the calculated energy.
Set mass to 2 kg and record the energy. Double it without changing height. Write one sentence that connects the output to the model's assumptions.Where this model breaks
Summary
Good notebook work makes inputs, units, code, output, and conclusion visible together. That makes a calculation easier to review and rerun.
Glossary
- Joule (J): the SI unit of energy.
- Constant: a chosen value that stays fixed for one experiment.
- Reproducible: another person can rerun the same steps and inspect the result.
Self-check
- Which values are inputs in this notebook?
- What test should pass at zero height?
- What conclusion is not justified by this model?
Sources
- OpenStax, University Physics Volume 1, energy chapter.
Model contract
Treat the lesson as a small function before treating it as a fact to memorize. Give every value a unit, keep only the state needed for the next step, and make the output easy to inspect.
\[\text{observable output} = f(\text{inputs},\,\text{state})\]- Inputs
- Quantities you set or measure, with units and useful bounds.
- State
- Values the program must retain to reproduce the next result.
- Rule
- The relationship or update that turns inputs and state into a result.
- Check
- A known limit, unit check, invariant, or measured result that can expose a bad model.
Implement the idea as a model
For Your First Physics Notebook, write down the quantities you can control, the values your program must retain, and the result a reader could inspect. In Physics as Computation, the useful program is not the drawing: it is the smallest explicit model that makes a prediction you can test.
Guided experiment
Prediction: changing one declared input while holding the others fixed should change only the outputs that the model connects to that input. Choose one input, predict the direction of change, then check a limiting case such as zero, a symmetric arrangement, or a familiar low-speed or small-change approximation.
Where this model breaks
This lesson is a teaching model, not a complete simulator. Before using it outside the stated question, check which interactions, scales, uncertainties, boundary conditions, and measurement limits it leaves out.
Summary
Treat Your First Physics Notebook as a contract: named inputs and units enter a rule, the rule produces an observable result, and a known limit or invariant checks whether the implementation deserves trust.
Glossary
- Input: a measured value or chosen parameter supplied to a model.
- State: the smallest set of values needed to continue or reproduce a model.
- Validation: comparing an output with a known result, limit, invariant, or measurement.
Self-check
- Which values are inputs, and which values must remain state?
- What observable result would tell you the model is behaving as expected?
- Which assumption would you test first before applying the model to a real system?
Model review: turn Your First Physics Notebook into a test
Build a small browser notebook that names constants, runs a model, reads an output, and records a conclusion.
- Name the inputs and units that the physics as computation model needs.
- Separate the state you must keep from values you can calculate when needed.
- Write one rule that maps the current state and inputs to an observable result.
- Choose a limiting case, unit check, invariant, or known result before trusting an output.
- State one assumption you would change before using this simplified model for a real decision.