Liquid or Solid?
Thanks to BBC Norkolk kids website http://www.bbc.co.uk/norfolk/kids/science_experiments/curious_custard/custard_01.shtml
Put some custard powder into a bowl.
Mix it with water while stirring until it feels weird; you’ll know what I mean when you feel it! Try running a spoon handle through the custard mixture.
The spoon should leave a clean cut groove that swiftly fills with liquid custard again. Or try sticking your finger in - the custard should stick to your finger!
Pick some of the custard mixture up and roll it into a ball between your hands. It feels slimy! If it is not mixed properly, you won't be able to do this.
Keep moving it - what happens if you stop? If you keep rolling it the custard forms a solid-like ball, but as soon as you stop...
..it runs away like a liquid. Yes, it is messy, but don't panic. When the mix dries out you can just brush the powder out.