Gravity: people, evidence and collaboration
G4.1 G4.2 G4.7
By the end of this lesson you should be able to
- Appreciate the significant contributions of scientists such as Isaac Newton, Johannes Kepler, Émilie du Châtelet and Katherine Johnson who furthered our understanding of gravity and motion. G4.1
- Explore the role of forensic evidence used in court and the challenges associated with providing conclusive evidence that may lead to convictions. G4.2
- Explore the international collaboration required in the discovery of gravity waves and associated technologies, e.g. Laser Interferometer Gravitational Wave Observatory (LIGO). G4.7
Key ideas
- Newton unified falling apples and orbiting moons with one law; Émilie du Châtelet translated and extended the Principia.
- Kepler used Tycho Brahe's measurements to find elliptical orbits. Katherine Johnson calculated trajectories for NASA's early crewed flights.
- LIGO (with international partners) detected gravitational waves in 2015. It took huge collaboration and extremely precise measurement.
- Projectile physics is used in forensic analysis (e.g. reconstructing trajectories), but courts need evidence beyond reasonable doubt, so uncertainty matters.
Common mistakes
- Treating scientific models as fixed facts: they change as evidence improves.
Do
- Read: Textbook (Oxford Physics for Queensland Units 3 & 4) section 5.1
- Do: CYL 5.1 Q1, 2, 3, 5
Try it
Watch
- The Absurdity of Detecting Gravitational Waves · Veritasium
Further reading
- OpenStax Physics 7.1 Kepler's laws of planetary motion (OpenStax, CC BY 4.0)
- Full topic notes: Gravity & Motion