Sun - Day One

Today the sun is out, the sky is blue and the cicadas are singing, this afternoon we will be on the beach but we spent this morning exploring rainbows as Rose has been asking for a rainbow day for ages.

We managed to pack in three activities with varying degrees of success.  First we made our own mini rainbow by refracting light through a glass of water.  This is pretty simple, you can get an explanation here.  Just take a glass of water and put it in sunlight in front of a piece of white paper, tilt it about a bit until you get the angle right and voila.  We made it an experiment by using different sized and shaped glasses to see which produced the best rainbow and we proved it was the water not the glass that refracts the light by trying to use empty glasses.  Here is our best one, you'll have to look close its tiny and try to ignore the hairy arm and chipped toenail varnish.

Next we mixed the colours of the rainbow using only primary colours and painted pictures of them.

Finally we tried to make a rainbow in a glass, I found this on About.com.  It really has nothing at all to do with light but is all about separation of liquids with different densities.  You make up four sugar mixtures with equal quantities of water but different amounts of sugar and use food colour to make them blue, green, yellow and red.  Then pour them into a glass (over a spoon like a barista) heaviest first and lightest at the top so they float on top of each other.  There was lots of measuring and stirring for this activity.  I don't think the kids were really impressed, it made this neat final photo though.