Polarization

(p 273) Only transverse waves can be polarized-light can be polarized If the polarizing axis of the two filters are in the same direction, then the light can pass through (p274)If the polarizing axis of the two filters are perpendicular to each other, then the light can not pass through

(p273)The fact that light can be polarized indicates it is a transverse wave (p274) we wear sunglasses (vertical polarization filter) to reduce glare (as glare is mostly reflected horizontally):

Scattering (p 275)Why is the sky blue? Tiny particles that make up the air scatter the light from the sun, but the shorter waves (high frequency) are scattered most the blue end of the spectrum (high frequency, short wavelength) is scattered by the atmosphere

Bright clouds are white because the water molecules in the clouds will scatter all light