Principle: Surface Tension
Interaction: Children age 8-10 can observe the effects of milk, color dye, and soap with a wind up cow toy. After placing all the liquids in a container, children can wind up the cow and place it in the milk. The amount of winding will effect how much the colors are mixed.
Cost: $5 for milk (more if experimenting with different types of milk), $2 color dye, and $5-10 for windup cow toy
Durability: Wind up toy might not last if used / wound too much
Safety: Safe if there's no consumption
Reflection: I thought about how to jazz up a science experiment. My elementary school teacher let us play with these set of liquids to experiment and learn about surface tension. Kids can notice a lot of things, even at a young age. I remember it was noticeable that the color dye and milk resisted less as time went on so not all toys have to be games. I think observation is critical to learning and it doesn't always have to be about competition.