Refraction is when light changes direction and speed as it passes from one object to another. Only visible objects reflect light. When two materials with similar reflective properties come into contact, light will pass through both materials at the same speed, rendering the other material invisible. Check out this video from BritLab on how to turn glass invisible using vegetable oil and pyrex glass.

'Tis the season for gumdrops and this classic structural engineering challenge uses just two ingredients: toothpicks and candy. We’re particularly fond of this one from The Homeschool Scientist because it helps you explain what the concepts (engineering, load distribution, physics, shape comparison) are to your kiddos while they are building it. doing it. Visit The Homeschool Scientist to get going. And click here for five more gumdrop-themed challenges. 
Be careful: The water only has the power to make the sugar crystals “invisible” when it’s piping hot. After the water cools down and evaporates, the sugar turns back into a solid. And with a little help of your sugar-soaked string, the crystals will find a home to grow upon and become rock candy. Learn how to make your smart sweets with these instructions from the Exploratorium. 
My First Mind Blowing Science Kit also comes with cool scientific tools like test tubes, pipettes, stirring sticks, and measuring scoops that will make your child feel like a real chemist. Not only will they learn important skills in conducting experiments, they will also learn the basics of acids and bases. While none of the experiments are particularly messy, it’s safer to perform them on a flat surface with adult supervision.