Every time you check a speedometer, time a sprint, or watch a radar gun flash at the side of the road — you are witnessing speed measurement in action. This complete guide covers everything from the basic formula to the science behind police radar guns and the ultimate speed limit of the universe.
Have you ever wondered whether anything in the universe is truly still? Physics gives a surprising answer: motion and rest are not absolute — they are always relative. Understanding this idea is the gateway to classical mechanics and one of the most profound insights in all of science.
Every object, whether solid, liquid, or gas, is made up of tiny particles: atoms and molecules. These particles are in constant motion, even if that movement isn’t visible to the naked eye. When we heat an object, we give its particles additional energy.
Why are the soldiers, who usually march in front step when crossing the bridge, are ordered to go “at ease”? Because marching across the bridge, they can destroy it. This happens due to an interesting physical phenomenon – resonance. However, the phenomenon of resonance is actively used not only in physics. For example, the term “public resonance” means the reaction of a large number of people to some event, political, economic, or social. But in our article, we will talk specifically about physical resonance, its significance in physics, causes, and the most striking examples from life.
The friction force arises from the contact of the surfaces of two physical bodies. The theory of friction worried the minds of mankind, since the earliest times. Ancient engineers: builders of the Egyptian pyramids, Stonehenge in England or mysterious stone idols on Easter Island, all of them (as well as their modern colleagues) were dealing with the problem of friction and how to minimize it. It is difficult to move heavy loads due to the friction force. Our distant ancestors invented such a useful invention as the wheel and many other important discoveries to solve this problem. In our article, we will look at the friction force in the physical aspect.
Fusion is the process of transforming a body from a solid to a liquid state under the influence of temperature. A classic example of fusion from life is the melting of ice, its transformation into the water, or the transformation of a solid piece of tin into a liquid solder under the action of a soldering iron. The transfer to a body of a certain amount of heat can change its state of aggregation; this amazing property of solids to turn into liquids under the influence of temperature is of great importance for science and technology. Scientists (as well as technicians, engineers) need to know at what temperatures certain metals melt (and sometimes not only metals), and for this, such a concept as “enthalpy of fusion” has entered into physics.
Inertia in physics is the ability of bodies to maintain a state of motion for a certain time in the absence of external forces. However, the concept of inertia is often used not only in physics but also in our daily lives. For instance, the inert person is the person who does not show any initiative at all. Inert persons only do what others tell them, and they do it extremely slowly, without any enthusiasm. “It moves by inertia,” we say when we want to emphasize that something is being done without any meaning, but simply because of a habit acquired over the years. Thanks to such everyday examples the concept of inertia is clear, but the term “moment of inertia” requires a more detailed explanation.
Brownian motion (or Brownian movement) is the chaotic and random motion of small particles (usually molecules) in different liquids or gases. The cause of Brownian motion is the collision of small particles with other particles. What is the story of the discovery of Brownian motion? Why is Brownian motion so important in physic and chemistry? What are some examples of Brownian motion in real life? Read about all this in our article.
Oxygen plays a leading role among all the known chemical elements. Life on our planet wouldn’t arise without oxygen. Oxygen is the most common chemical element on Earth, accounting for 49% of the total mass of the earth’s crust. Oxygen is also part of the Earth’s atmosphere; part of the composition of water, and the composition of more than 1,400 different minerals, such as basalt, marble, silicate, silica, etc. About 50-80% of the total mass of tissues, both animals and plants, consists of oxygen. The important role of oxygen for the breathing of all life is well known.
The word “diffusion” of Latin origin – “diffusio” in Latin means “spread, dispersion.” In science, diffusion is the process of the interpenetration of microparticles upon the contact of different materials. The academic definition of diffusion is: “Diffusion is the mutual penetration of the molecules of one substance into the intermolecular spaces of another substance due to their chaotic motion and collision with each other.”