Tomorrow (20th March 2015) is the first time the UK will experience a Solar Eclipse since 1999! I actually remember the last one, and I remember all the build-up & warnings that went with it. The next Solar Eclipse in the UK won't be until 2090, so it's well worth watching if you can do so safely (I'll explain more later).
If you were from an ancient civilisation you wouldn't be at all excited about an eclipse as it was seen as a sign that the world was ending. In Greece it meant that the Gods were angry; eclipse comes from the greek ekleipsis which means abandoned/obscurred. In China it predicted the future of the emperor, the Chinese were actually quite good at predicting eclipses, even as far back as 2500BC!
Although we now know what causes an eclipse there have been some very interesting theories! The Vietnemese thought a frog was eating the Sun (obviously), Vikings blamed wolves, others thought a dragon was eating the Sun and in Siberia vampires were to blame.
So what actually happens during an eclipse? Well solar eclipses only happen when the Sun and the Moon perfectly align themselves. For this to happen the Moon has to be in it's new phase, and at it's closest point to the Earth (normally known as a Supermoon). Combined with an Equinox Sun, this means that the moon passes directly in front of the Sun, and because it is at it's closest point to the Earth it appears to be the same size as the Sun, thus blocking out the light.
Staying safe during a solar eclipse is paramount, so only look up at the sky if you're wearing certified eclipse viewing glasses and even then do not look at the Sun for long periods of time. The glasses should be brand new (not recycled from 1999) and should have no imperfections on the lens. Do NOT take photos with your smartphone, you can burn out your camera. Do not look at the Sun with naked eyes, the UV will burn your retinas and cause blindness. Sunglasses do not provide protection during an eclipse, they can trick your eyes into letting in more light thus causing severe damage. Do not use telescopes or binoculars.
You can view the eclipse safely; either using eclipse glasses, making your own pinhole camera, or watching the live stream which will be on TV & the internet.
The Eclipse is expected to last 2 hours from start to finish, but how long it affects you will depend on your area of the country. The further north; the longer it will last & the larger the percentage of the Sun that will be covered by the Moon. If you live in the South, it will start earlier and will not be as much of an eclipse. More details of this can be found by doing a quick search on the internet.
I hope you get to see this eclipse one way or another, but make sure you stay safe please!!!