When I was a pre-school teacher I came up with the idea to put marbles and buttons into ice cube trays and then pour all of the cubes into our sensory table. The kids loved using the warmth of their hands to melt the cubes and collect the treasures. I new that the boys would love this activities but I new the cubes would go right into their mouths and then they would pose a choking hazard. So I came up with a toddler safe version. I used a muffin tin and these ocean themed linking rings. Fill the tin half way with water if your object floats, after that layer freezes then fill it the rest of the way.
When it was time to play I knew the boys wouldn't have the patients to use their hands to melt them so I put out a pan of warm water. The boys loved this activity and next time I plan to talk more about ice, water, melting, cold, and warm. This time it was just for fun and we talked about colors too!