A rail is a long, thin piece of wood or metal that is fixed in place horizontally. Rails are often used like in the picture as a guard to stop people going past them. They can be fixed to a wall as a support somewhere people might need them, like in a shower cubicle.
A special type of rail is found on a railway track.
Clouds are made out of tiny droplets of water. As a cloud gets bigger and bigger, the droplets join up and become bigger too. Eventually the droplets get too big and heavy to stay up in the air, and they fall as rain.
Words that sound the same as rain but are spelt differently are reign and rein.
Rainbows happen when the sun shines through a very fine spray of water, like rain in the air or the spray from a garden hose or even from a waterfall.
The rainbow is colourful because as sunlight travels through the water spray, it splits into a spectrum of colours. All the colours you see in a rainbow are there all the time in normal light, but they are mixed up together so you only see white light.
You can also see the colours of the rainbow by shining light through a prism.