Gravity Assist: the Planetary Slingshot
How does a gravity assist, or slingshot, work exactly for a spacecraft skimming around a planet? Where does the momentum gain come from? Continue reading Gravity Assist: the Planetary Slingshot
Category: Secondary ed level
Why is glass transparent?
If all things consist of molecules, why is it that some materials are transparent while others aren’t? Why is glass transparent? Continue reading Why is glass transparent?
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
Spaces and dimensions
What do mathematicians and physicists mean with phrases like higher and/or extra dimensions? Let’s travel through a Universe of spaces and dimensions! Continue reading Spaces and dimensions
Quantum mechanics in ten ideas for people on the move
If you’re on the move, you don’t have much time. Here are ten important ideas from quantum mechanics you can catch up on. Particles and wave functions! Continue reading Quantum mechanics in ten ideas for people on the move
Complex numbers: an introduction
We will leave the domain of real numbers behind us and start exploring the plane of complex numbers. An introduction to a realm beyond imagination. Continue reading Complex numbers: an introduction
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
Quantum entanglement: the EPR paradox and Bell’s Theorem
Einstein didn’t like that quantum entanglement seemed to imply information travelling faster than the speed of light. We discuss Bell’s Theorem. Continue reading Quantum entanglement: the EPR paradox and Bell’s Theorem
Quantum entanglement: non-locality and the state of a two-particle system
In this two-parter, we discuss quantum entanglement, non-locality, and some mathematics. In the next post, we discuss the EPR paradox and Bell’s Theorem. Continue reading Quantum entanglement: non-locality and the state of a two-particle system
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 hasn’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. Let’s observe this carefully. Continue reading This is not an atom
Proof that the square root of 2 is irrational
We will provide the proof that the square root of 2 is irrational through a proof of contradiction. We will show no valid ratio of integers exists. Continue reading Proof that the square root of 2 is irrational
The meaning of E=mc²
The most famous equation may not be what you think it is. For example, it’s not about converting mass into energy. And, it’s only a part of the whole thing. Continue reading The meaning of E=mc²
Einstein’s special relativity in under 6.999 minutes for people on the move
Especially for people on the move, we discuss as briefly as possible the intricacies of Einstein’s special relativity. Continue reading Einstein’s special relativity in under 6.999 minutes for people on the move
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
A radioactive smoking gun
Even physics tells us that smoking is bad. We briefly discuss what radioactivity is, what ionising radiation is, and how radioactive lungs become. Continue reading A radioactive smoking gun
Just a minute: how do polarized sunglasses work?
We briefly discuss how polarized sunglasses work, quantum fields, pilots, and 3D cinema. Continue reading Just a minute: how do polarized sunglasses work?
Is microwave oven radiation unhealthy?
We discuss what electromagnetic radiation is and why ionising radiation is dangerous. We discuss how a microwave oven heats up food, and vitamins too. Continue reading Is microwave oven radiation unhealthy?
Why, exactly, do glass and liquids refract light?
We provide a semi-in-depth look into why glass and liquids bend light. We discuss quantum fields, Maxwell’s equations, and vectors. No calculations. Continue reading Why, exactly, do glass and liquids refract light?
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: what is a black hole?
What is a black hole? We briefly discuss the Schwarzschild radius. Continue reading Just a minute: what is a black hole?
Just a minute: how big is the universe?
In case your child asks how big the universe is, this is something you quickly might want to read. Continue reading Just a minute: how big is the universe?
Happy birthday mister Einstein, happy Pi Day to you!
Pi Day is the day on which we commemorate Albert Einstein’s birthday. Also, people celebrate the existence of pi. Here are some cool ways to calculate pi. Continue reading Happy birthday mister Einstein, happy Pi Day to you!
The formula that got Albert Einstein the Nobel Prize and should stop us getting sunburn all the time
Albert Einstein didn’t win the Nobel Prize with his famous formula from the special theory of relativity. What formula did he win the Prize with then? Continue reading The formula that got Albert Einstein the Nobel Prize and should stop us getting sunburn all the time
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
When and why do you multiply probabilities?
At high school you may have been taught that, sometimes, you have to multiply probabilities. We briefly discuss when and why you do this. Continue reading When and why do you multiply probabilities?
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