Category
From light to electricity: articles that explain the laws of physics behind everyday events through intuition and experiments.
NewestPhysics
In 1831 Michael Faraday pushed a magnet into a reel wound with copper wire and the galvanometer needle moved; when the magnet stopped, the needle went back to zero. We explain how changing magnetic flux drives a current, the law ε = −N·dΦ/dt, Lenz's law, generators and transformers.
Kuazara Bilim Ekibi13 min read
Between 1909 and 1913 Robert Millikan measured the charge of the electron by watching micron-sized oil drops float between two metal plates through a microscope. We explain the apparatus, Stokes' law, the qE = mg balance and why every charge came out as a whole multiple of e.
10 min read
In 1909 Geiger and Marsden fired alpha particles at thin metal foils; most went straight through, but a few bounced back. We explain Thomson's plum pudding model, the apparatus, Rutherford's nuclear model and the 1/sin⁴(θ/2) scattering formula with a simulation.
10 min read
In 1851 a 28-kilogram ball was hung on a 67-metre wire from the dome of the Panthéon in Paris. As the hours passed, its plane of swing slowly turned against the floor. We explain why it turns, why the rate depends on latitude, and how long a full turn takes in Istanbul and Ankara.
9 min read
Light passing through two thin slits leaves bright and dark bands on a screen. We explain the idea of interference Thomas Young put forward in 1801, the fringe-spacing formula, experiments with single photons and electrons, and why the pattern disappears when we measure "which slit" was used.
11 min read
Why can bright red light fail to free a single electron from a metal, while dim violet light frees them at once? From Hertz to Einstein and Millikan, we explain the photoelectric effect, the threshold frequency and the stopping voltage with a worked example.
13 min read
A steel ship weighing thousands of tonnes floats, while a stone that fits in your palm sinks. The answer is not weight but density. We explain what density is, Archimedes' principle, why ships do not sink, and a safe egg experiment you can try at home.
7 min read
Aristotle said heavier objects fall faster; Galileo disagreed; in 1971 an astronaut dropped a hammer and a feather together on the Moon. The story of free fall, air resistance and a safe paper-and-book experiment you can do at home.
6 min read
Why do all the bulbs go out when one bulb in a series string fails? Why are the sockets in your home wired in parallel? We explain series and parallel circuits using Ohm's law, with a worked example and notes on electrical safety.
10 min read
Why do we see the lightning first and hear the thunder later? We explain how sound travels, how fast it moves through air, water and steel, and how a simple calculation tells you how many kilometres away a storm is.
8 min read
Sunlight is white, so why is the sky blue and the sunset red? We explain Rayleigh scattering step by step, why we see blue rather than violet, and why clouds stay white.
10 min read