Water is most dense around 4 degrees. The bonded molecules in ice have started to break up but not fully; they interlock more closely.
I love weather trivia. A rainbow is effectively water refracting once through a water droplet; the area inside the rainbow is therefore quite light. Double rainbows are when some light particles get refracted twice before leaving the water droplet; the colour order is reversed and the light scatters into the expanse of sky beyond the second bow. The 'angle' between the first and second refractions contains no light (or much less?) and is the space between the two bows - it's called Alexander's Dark Band.
The great book 'The Cloud Collector's Handbook' taught me (don't know WHY it never occurred to me before) that sunsets are red/orange because the light is curving round the earth and travelling through more atmosphere before we see it; most of the light at the blue end of the visible spectrum is scattered. Raleigh scattering gives blue sky - when sun is overhead & travelling through a thin, clearer band of atmosphere, little is scattered and we see the blue end of the spectrum. Cloud makes all the light scatter so the sky appears white. Also water droplets in the upper atmosphere can be supercooled well below zero degs; they only freeze if there is something to cling onto, like dust or pollen.
Some Pink Floyd trivia: there is a hidden message at the start of the song 'Empty Spaces', recorded 'backwards'. It only says something like 'Well done you have found the hidden message.' Each of the beds on the beach on the Momentary Lapse of Reason album cover picture weighs a ton.