This is a wonderful activity to do with children and young people (adults too) and something you can do with your own kids (it is soooo cheap, just paper plates, emplty jars, chalk and salt)
Mostly kids just want time with their parents (or a different, non-conflict kind of time) and this sort of activity can't be done wrong; it doesn't matter if you get covered, or you furniture gets covered, it all hoovers up and not a bit of it will stain!
Trust me, I am a legend for being covered in salt, chalk and glitter!
What is it? Layers of diffferent coloured salt in a jar
How do I do it?
1. Pour some salt onto a paper plate (just a small layer at a time)
2. Take a coloured chalk and rub the salt (holding the chalk horizonatally works best) - the harder you press the more vivid the colour becomes.
you can mix colours, just as you would with paint.
3. When you are happy with the colour, fold the plate up and pour the first layer into your jar.
4. Start again with a layer of a different colour
5. To make swirls of 'stalagmites' you can prod a paintbrish or biro into the jar near the glass to make the layers merge into each other
Just don't shake it up unless you want all of your layers to mix together, although that can look pretty too!
KEEP GOING UNTIL IT OVERFLOWS as otherwise it can easily get knocked and the layers change their positions.