1. Red sunsets can be more impressive when there is dust or pollution in the air because for the sunset to be like that the sun has to shine on something denser then air e.g. dust, pollution or even a cloud.
2. The things that happen inside a water dropplet to cause a rainbow is light going through it and refracting into whatever colours of light make up white light e.g. red, orange, yellow, blue, green, indigo and violet. You can tell if a rainbow is primary or secondary because primary rainbows are formed by light reflecting inside the rain droplet once but secondary rainbows are formed by light reflecting in a rain droplet twice.
