How to learn the basics of physics Part 2

2017-08-15 by No Comments

Also possible to study the thermodynamics of the law, the processes of direct and reverse Carnot cycle. To study, for example, why the internal combustion engine (and any heat engine) is the ultimate real efficiency and equal it is, of course, not 99% or even 70%, and about 40%. In the study of the working gas is necessary to examine the principle of operation of air conditioning and refrigerator. In the study of the properties of gases to study why the standards did not make the gas supply in the homes of more than nine floors, the danger can create gas cylinders (in the last year, one man loaded a gas cylinder to the eyeballs in the frost, and then put him in his warm apartment, the balloon burst and killed his entire family).

When studying the motion of liquids through pipes to study why, for example, it is impossible sharply to open the valve when filling the system with water or sanitation unit. You know how the sewage in your house? For example, why is a manhole riser placed on the roof. Or why the trap may disappear water (bad sign by the way!). And so on. See what’s around you. Even it is possible to study from theory to practice.

Complex topic electricity. That is, it is of course simple, but usually it becomes a kind of stumbling block. Probably because the electricity is “invisible”, in contrast to the mechanics or even thermodynamics. Walking wires, suitable to different kinds of refrigerators and TVs, but how and where it is unclear. I have told how I was explaining to the people what is the voltage and current, but it is very simple. With such important phenomena as magnetism, static electricity, the discharge is more complicated. And we are surrounded by motors and generators (magnetism) and lamp housekeeper (gas discharge). And statics is also widespread. Walk in septic sweater, then take hands some tender fee, say DDR3 4 GB and it can quietly for you to die. Man after all a thousand volts to keep can.

Murky topic quantum phenomena. For example, the work of led and semiconductors in General can explain only by knowing the relevant sections of quantum physics, and they are extremely complicated. Therefore, do not need to climb. Just know that the led is illuminated, the crystal, and not red-hot spiral as in a conventional bulb and not a gas as in the housekeeper. About the diode, it is sufficient to know that it conducts current in one direction, and about the transistor it has magnifying properties. Not know quantum physics it is normal. We’ve had a cool teacher physicist at the Institute, but he once secretly confessed to us not to understand really as an elementary particle overcomes a potential barrier? But I’m still really do not understand how pn junction works, which, in General, does not prevent me to develop and collect scheme.

Again, it is important to see the connection. In physics in General, everything is connected. Any known physical process can be described with just seven units, and now, if anyone heard of physics are struggling with the creation of a “unified field theory” that is the theory linking the four types of the known physical interactions. But here until everything came to a halt. Stalled on gravity. I can explain its mechanism.

I remember how one day I “suddenly” saw that the formula of the kinetic energy mV2/2, the formula of energy of the charged capacitor CU2/2 and the energy of the inductor LI2/2 is similar. I never liked school definition of inductance as the proportionality factor between the current running in the closed circuit, and the magnetic flux created by this current through the surface limited circuit. No, well, like it is, but to “work” this definition was uncomfortable. Formula it is no accident similar. And inductance there is in the place of the mass. And the fact that the current is “speed” is intuitive. So inductance is “weight”! Mass in mechanics prevent an instantaneous speed change.

The inductor prevents an instantaneous change of current in the circuit the sudden cessation of current occurs EMF of self-induction, thanks to her, we can use batteries of several volts to “take out” tens of thousands of volts, this principle operate the stun guns, generators “spark” in cars etc. it is Clear that the mass, capacitance and inductance scalars. That is, like a lot of inductance can store energy (magnetic field) and to prevent abrupt change of the parameter which is actually a “supplier” of energy (current). Same thing with capacity. Capacity prevents a sharp voltage change. Because of these delays (current across the inductor and the voltage across the capacitance) occur, all of these phase shifts which lead to big energy losses (according to different sources up to 20%). These things also do not pay attention.

In the section “Optics and waves” it is important to pay attention to the dependence of the propagation of their length. Because of this, having a low power you can keep in touch with the world, and a powerful VHF (FM) stations are not always heard when leaving the city. Same with microwave communication, for example, we take the signal to the dish antenna from the satellite which has a distance of 36 000 kilometers, and at the same time to us cannot finish signal from the television antenna located at a distance of 50 kilometers. Well, of course the Doppler effect it gutsy catch drivers exceeding the speed. Thanks to him changing the tone of an automobile horn when approaching and auto removal. We can also add strobe effect: why in old movies often the wheels of the carriage revolve in the direction opposite to the movement? Although it is clear that in reality they are spinning in the right direction.

In General, you get the idea. Teach only what I see around me. That directly feel. But it is learning for yourself.