Going old skool with cups and strings to make it like a phone, making a grass head and they can watch it grow

I bought a small whiteboard that fit on my daughters lap. At 1 she enjoyed drawing circles and then wiping them and redrawing. Would do it for ages. It’s good for motor and mental skills too.

Slime- cornflour & water.
Volcanoes- bicarb & vinegar.
Pipes- literally a $2 drain pipe from Bunnings where you can balance anywhere during the house and release balls and cars down it. So much fun!!!!