our team will present you today about waves .
To begin with ,what kind of waves could you think of ?
light micro sea electronic magnitic heat brain
Additionally ,how do the waves work ?
Is there anyone who could answer this question ? Anyone majors in physics ?
Actually，the way a kind of wave works depends on its on nature ,however ,they do have some common points .Is there anyone know what' s that ?
Fluctuating with regular frequency and amplitude ,waves transfer information and energy.
Let's take radio waves as an example . They travel through the air at the speed of light . When the waves arrive at the receiver antenna, they make electrons vibrate inside it , which produces an electric current that recreates the original signal .
Another example is electromagnetic wave. As is illustrated in the picture, the electronic field and the magnetic field are perpendicular to each other.In the high-frequency electric oscillation, the magnetoelectric conversion rate is very fast. As a result , the energy can not be all back, which propagates to the space with the periodic changes of electric field and magnetic field in the form of waves. This is exactly the electromagnetic wave.
In fact ,the production of electromagnetic waves is essentially due to the movement of the charged elementary particles inside, which in turn is essentially dependent on their intensity of the movement .Besides, The elementary particles are at rest only at zero kelvin . So all substances radiate electromagnetic waves to the outside world, while absolute zero-degree substances do not exist. Therefore everything in the universe is producing electromagnetic waves. When humans have not yet know the principle of electromagnetic waves, the ones you could see are called "light."
Right , in our information era , we are exposed to waves anytime and anywhere.
Defenitly, waves share an indispensible part in our daily life , on the contary, waves are somehow casting influences on us . We see pregnant women wearing radiation-proof clothes ,we also see killer boats sent out fault signals to catch whales and dolphins . Although what direct damages waves bring in human body have not yet been clear ,it does exist and always remain a controversial problematic .
As a result, in this presentation ,we will examine both the merits and adverse impacts the waves have on human body before outling several suggested resolutions .