Water is a superb solvent; 3.5% of the volume of our oceans are minerals such as salt. We discussed how these minerals can travel from the tops of the mountains and through the rivers to ocean. (Remember our water shed demonstration?) Evaporation and the addition of fresh water greatly change the salinity of water.
I defined density and salinity and explained that the higher the salinity, the higher the density. To show this, I poured 1 teaspoon of salt onto a saucer and 3 tablespoons of salt onto another saucer.
We floated eggs in our “ocean water” and in our plain water. I first did this in small glasses, then replaced half of the salt water with plain water to demonstrate how the salinity changes when it rains.
I then set them loose with toys to play for the day. 🙂
I asked if they wanted to taste the water- surprisingly, no one did!
I love nature study!