Sometimes when we talk about 2 people who don’t get along, we might say they are like oil and water. We mean they don’t mix well together. Have you ever tried to mix oil and water? Even if you stir or shake the solution, the oil and water eventually separate.

Have you thought about why oil and water don’t mix? It’s all related to a concept called density.

The Background Matters

Matter is what makes up a substance or object. It’s anything we can touch, feel, or see. The wind, your shirt, a bird, or lemonade are all types of matter. Matter exists in 4 states- solid, liquid, gas, and a special, charged gas called plasma. Matter is made of atoms and molecules that have energy; how quickly those atoms move around is based on its state. A solid has the least amount of energy; its atoms move slowly. A liquid’s atoms move a bit more rapidly. A gas has the most energy; its atoms fly about speedily, bouncing off each other and the sides of its container.

Every state of matter follows the same principles meaning they act according to consistent properties. For example, we know we can pour a liquid. It’s one of the properties that make it a liquid! Solids, on the other hand, don’t pour. We can observe these consistent properties repeatedly, and they’ll behave the same every time.

What is Density?

All matter mass and density. Mass is how much matter is packed into an object/substance. We calculate mass in grams, pounds, and ounces. Continue learning about density at The Mystery of Science!