PHYS 0847 Lecture 8: Physics - Chapter 8
Document Summary
Sound requires a material to travel in because it is carried by the motion of molecules. There is no sound in outer space because there is nothing to carry the sound. It is carried by electric and magnetic fields. Since it is a wave, it undergoes many of the same behaviors we saw in the last chapters such as refraction, interference, and the doppler effect. But unlike sound, light is not carried by air molecules. The ele(cid:272)t(cid:396)i(cid:272) i(cid:374)te(cid:396)a(cid:272)tio(cid:374) (cid:271)et(cid:449)ee(cid:374) (cid:272)ha(cid:396)ges (cid:272)a(cid:374) (cid:271)e said to (cid:271)e (cid:272)a(cid:396)(cid:396)ied (cid:271)(cid:455) a(cid:374) a(cid:271)st(cid:396)a(cid:272)t (cid:862)field(cid:863) (cid:272)alled the electric field. The magnetic interaction between currents can be said to be carried by an a(cid:271)st(cid:396)a(cid:272)t (cid:862)field(cid:863) (cid:272)alled the (cid:373)ag(cid:374)eti(cid:272) field. These fields a(cid:396)e (cid:374)ot (cid:373)ade of (cid:396)eal (cid:373)atte(cid:396) (cid:894)like ai(cid:396)(cid:895). They are just sort of an abstract, ethereal thing that can be around us, even in empty space. Light is carried by a wave in the electric and magnetic fields.