Hobbies And Interests
Salt Crystallization
Children can learn about the atomic makeup of salt by doing a simple experiment with water and a little help from sunlight. By dissolving 1 tablespoon of salt in a 1/4 cup of water, and allowing the water to sit in a bowl and vaporize over a few days, the dried-out portions of salt left over will be crystallized. Under a magnifying glass or microscope, it's easy to see how the crystals will have formed into cube-like, repeating 3-D components known as halites, which is a type of mineral. You can then explain how the chemical components of sodium and chloride, when bonded together, form the mineral of common table salt.
Floating in Saltwater
Salt also can be used to demonstrate how it can affect the weight and density of liquid by adding it to an ordinary glass of water. When salt dissolves into the water, the sodium and chloride ions bind to the water molecules of hydrogen and oxygen, creating more weight and taking up extra space inside the glass. The water thus has become denser and thicker, and will now be able to support limited items on the surface, causing them to float. You can prove this by taking two glasses of water, and adding 6 tablespoons of salt to one of the glasses. Take two raw eggs fresh from the carton and place one inside each glass. The water glass containing the salt will keep the egg floating, while the other egg will sink in the unsalted water.
Food Coloring with Milk
Children can unlock some artistic creativity with this next experiment. Add a few different drops of food coloring along the sides of a small glass plate of whole milk, the fattier the milk the better. You'll notice that once the drops are added, they won't dissolve immediately. This is because the food coloring is less dense than the milk it's sitting in, and the surface tension of the milk against the glass, due to the fat molecules inside, keeps the drops from moving. Add just a drop of dishwashing soap to the center of the plate and the magic happens. The fat molecules in the milk start to absorb into the soap, causing less surface tension on the milk surrounding the soap drop. The food coloring will push away from the drop and gradually sink. You can show children how to make fancy designs with the colors by placing a dollop of dishwashing soap on a toothpick and swirling it slowly through the food coloring to make a tie-dye effect.
Food Coloring for Flowers
Children might sometimes notice seeing different colored flowers that are normally white, and wonder how the effect was done. Using food coloring in some water, you can show them. Take three or four white, stemmed carnations, cut a bit off the ends of the stems and place the flowers in tall glasses of water that contain different types of food coloring. After a few hours, the petals of the carnations will start to gradually change into the color of the water they are in. This happens because the plants have tiny holes known as stomates. Usually when a plant is inside soil, it depends on the roots to collect the water from the ground to help it grow. Without roots, the carnations are counting on the stems instead, and as the colored water is evaporated into the stomates, the color appears on the carnations. Children can be more creative by splitting a carnation stem in half and placing the two halves in two different colored water glasses. The carnation's petals will change into the two colors.