# The Copenhagen interpretation

We will have a look at the Copenhagen interpretation as proposed by Niels Bohr and Werner Heisenberg to explain the stranger things in quantum mechanics. Continue reading The Copenhagen interpretation

# Heisenberg’s uncertainty principle

Heisenberg’s uncertainty principle is famous in quantum mechanics. However, it doesn’t have its roots in quantum mechanics. Let’s look at Fourier transform pairs. Continue reading Heisenberg’s uncertainty principle

# Lab centrifuges and prime numbers

Lab centrifuges are crucial in e.g. coronavirus research. It’s vital the test tubes are balanced. There is an easy method to know if that’s possible. Continue reading Lab centrifuges and prime numbers

# The double-slit experiment

We describe the famous double-slit experiment, which proved to be fundamental to our current understanding of quantum physics. Continue reading The double-slit experiment

# The Collatz Conjecture

The Collatz Conjecture is probably one of the easiest to understand problems which hasnâ€™t yet been answered in the history of mathematics. Continue reading The Collatz Conjecture

# This is not an atom

The standard cartoon of an atom is incorrect. An atom is not like a tiny planetary system. Quantum mechanics is all about the wave function. Letâ€™s observe this carefully. Continue reading This is not an atom

# The meaning of E=mcÂ²

The most famous equation may not be what you think it is. For example, itâ€™s not about converting mass into energy. And, itâ€™s only a part of the whole thing. Continue reading The meaning of E=mcÂ²

# Rainbows: Alexander’s band

The band between the primary and the secondary rainbow is darker. The area underneath the primary rainbow is lighter. We explain Alexander’s band. Continue reading Rainbows: Alexander’s band

# Why do wet clothes dry?

We discuss the second law of thermodynamics, the notion of entropy, the statistical nature of the situation, and why wet clothes dry. Continue reading Why do wet clothes dry?

# Just a minute: why do large and heavy ships not sink?

Until they do due to a mistake, ships do not sink, not even the large and heavy ones. Now and then, textbooks say this is because of dissimilar density. Though not a a wrong statement, it is also not a fundamental one. While ships may sink to the bottom of the ocean thanks to gravity, they also float thanks to gravity. Continue reading Just a minute: why do large and heavy ships not sink?

# Mirror, mirror, what’s up with the mirror writing?

Ever wondered why sentences, words, and letters always exclusively seem to have their left and right reversed in the mirror, while they are almost never projected upside down? Probably, because mirrors do something else than you would expect. For starters, mirrors don’t reverse left and right. Continue reading Mirror, mirror, what’s up with the mirror writing?

# Why your coffee does not have tides

The moon orbits the earth and its gravity is causing the tides. But why don’t swimming pools have tides? Or a cup of coffee? Human bodies consist of water, mostly. Aren’t they tidally influenced by the moon? If you’re asking all these beautiful questions, then what you thought is causing the tides is probably wrong, and here’s why. Continue reading Why your coffee does not have tides

# Just a minute: Minus minus and negative times negative

Minus minus is plus. And negative times negative is positive. Two negatives make a positive. You may have heard or uttered these expressions many times. Even though you will know this already, here you will find an algebraic proof, just for your reference. Requirements: simple algebra from the second year in secondary, high or grammar school. Continue reading Just a minute: Minus minus and negative times negative

# Energy is neither fundamental nor conserved

Sometimes you may have heard someone say that, ‘in the end, everything is energy. Einstein himself said that mass equals energy, we are energy ourselves, light is energy, and everything in this universe is energy.’ Often, it is represented as the fundamental substance everything is made out of. And energy is conserved. Both statements are incorrect. Continue reading Energy is neither fundamental nor conserved

# The riddle of birthdays

Probabilities can be hard to grasp. For instance, what are the chances that among a birthday party’s attendants two or more people will have their birthdays on the same day? Probably better than you might expect. Continue reading The riddle of birthdays

# Happy New Year: Earth is Amazing

Happy New Year. Earth is amazing. Witness, in 4K, both the visual data and the audio recording of the crew of Apollo 8 when the iconic Earthrise photograph was taken. Continue reading Happy New Year: Earth is Amazing

# What is a spacetime interval?

Einstein and collaborators taught us that space and time are not fixed quantities. They can stretch and contract. They vary. There is one thing, though, that does not vary. It is the invariance of the spacetime interval. Continue reading What is a spacetime interval?

# Deriving the Lorentz transformations from a rotation of frames of reference about their origin with real time Wick-rotated to imaginary time

Well-known for their central role in Einstein’s Special Relativity, the Lorentz transformations are derived from the rotation of two frames of reference in standard configuration while time is taken to be an imaginary unit of spacetime. This is rarely seen in the wild. Not many undergraduate textbooks or online texts show the details of the working. Hence, this article. Continue reading Deriving the Lorentz transformations from a rotation of frames of reference about their origin with real time Wick-rotated to imaginary time