We starting talking to her about matter, liquids and solids when she was really young. Nothing big there, more of incidental learning where it's part of our daily conversations.
She started understanding that liquids have no definite shape and after watching Magic Schoolbus, she sort of have an idea of what molecules are and how they are different between solid and liquids. Taking this further, I decided to have some fun with gloop! You can also have some fun with gloop with the younger kiddos for sensory play since it is primarily non toxic with just cornflour, water and colouring :)
And of course, this was the perfect moment to let her to estimation and measurement... So we first added the flour
Then water (ratio of flour : water is 2:1)
Added in some food colouring for fun
Then the messy play began - she attempted to catch it
Then watched how it felt like "solid" when she caught it and attempted to mould it (force) and later became runny again. :)