Want to ask something?
Send us an e-mail with the subject “Physics mysteries” to the address:
We can't wait to tackle your interesting questions!
How wide is the rainbow?
In addition to visible light, there are other components in the electromagnetic spectrum — ultraviolet and infrared, radio and X-rays ...
Light colour is made by its frequency and as you write correctly, light is a type of electromagnetic wave and is specific “only” by that it is about the frequencies we see. The frequency of the electromagnetic waves can be arbitrary and so our perception is limited to a narrow part of the spectrum (in frequencies 1014 Hz) ...
Text in a car’s rearview mirror
Why is the ambulance sign on an ambulance reversed when looking in the mirror and it is clear that the sides of the displayed object do not change — what is to the right in front of the mirror i ...
A convex mirror is used in a car’s rearview mirror — this is the reason it always creates a reduced and inverted image. But the image that is created is reversed. If you want to shake your right hand with your image in the mirror, you will see for yourself. From our point of view, the hand is on the right, but in reality one would shake your hand from the left ...
Hypothetical rescue in a falling elevator
Can I save myself in a falling elevator by jumping just before impact?
I hope that no one will have to experience this situation because it will not be possible to jump in a falling elevator — I will explain the situation where we do not take into account the air resistance. If an elevator falls, the elevator will move with the acceleration of gravity g (we won’t count air resistance) ...
Lift forces on an aerobatic aircraft
How is it possible for an airplane to fly horizontally during aerobatics, even when it is upside down? The lift on the wings should pull him down and not up…
It is true that the plane takes off due to the geometry of the wings. The upper part is more bulging than the lower part and therefore the air flows at a higher speed around the upper part of the wing than the lower part. And it follows from Bernoulli’s equation that the higher the velocity of the fluid, the lower the pressure at a given location ...
Creation of vacuum by explosion
An explosion (e.g. a nuclear bomb) creates a pressure wave, i.e. air spreads outwards from the epicenter. Does this mean that a vacuum is created at the site after the explosion?
Yes, that’s right. A pressure wave is typically created by an explosion (it doesn’t matter what the source is) compressing the surrounding air. Because air is a flexible environment, this compression will spread further. You can try something similar yourself — just push water in a pool (or in a bath or pond) with your palm ...
