Physics is not just about choosing the right formula and substituting numbers.
In this video lesson, we use Newton’s second law, F = ma, to explore what happens before an equation can actually help us solve a problem.
You will see why a physics problem requires us to decide:
What is the system?
Which interactions matter?
What can reasonably be ignored?
Which relationships belong in the model?
What does the model predict?
How can that prediction be tested?
The lesson follows a simple reasoning chain:
situation → what matters → relationships → model → prediction → test
Two problems can use exactly the same equation while requiring different physical decisions. And two students can produce exactly the same numerical answer while using completely different reasoning.
That is why a correct result is not automatically evidence of understanding.
Formula = compressed representation.
Understanding = the ability to reconstruct the mechanism and reasoning behind it.
This lesson combines real physics with academic English. The language is not added as vocabulary practice around the subject: it is used to distinguish concepts, assumptions, relationships, predictions and explanations.
Related reading
Before You Solve a Physics Problem, You Have to Decide What the Problem Is
A deeper exploration of system boundaries, relevant interactions, models and the decisions that come before equations.
Read the article
Physics Is Not the Subject. Thinking Is.
The original Language Thinking Lab exploration of physics as a way of questioning, relating, explaining and reasoning.
Explore the original article
Learn Physics in English, German or Spanish
For learners who want to develop subject knowledge and use another language as a working language for physics.
Explore Physics + Language
Learn English Through Math and Science
A broader route for developing English through real mathematical and scientific reasoning.
Explore English through Math and Science
Across the Physics Thinking series
The same central idea is explored through different physical problems across the multilingual Levitin Language School ecosystem:
Deutsch — reference frames:
Bewegt sich der Zug – oder die Welt?
Русский — models and idealization:
Почему «неправильная» модель может дать правильный ответ
Українська — measurement:
Термометр показує 20 °C. Але що саме ми виміряли?
Polski — prediction and explanation:
Model przewidział wynik. Ale czy to znaczy, że rozumiemy, dlaczego tak się stało?
Español — causal testing:
Cambiamos una sola cosa. ¿Qué debería ocurrir?
简体中文 — scale and levels of description:
同一个世界，为什么需要不同尺度的物理模型？
About the Author
Tymur Levitin
Founder & Director, Levitin Language School / Language Learnings
Levitin Language School develops individual online learning across three independent but connected educational layers: Languages, Academic Subjects, and Language + Subject.
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