Third Grade Physical Science
We know that physical science studies the phenomena on earth and tries to understand the rules or causes behind these phenomena. We also know that physics, when applied, tries to create new and practical technologies for the betterment of life and society. One major study in the world of physical science or physics is energy. Everything on earth relies on some form of energy in order to live or function properly. Without energy, the world as we know it would not exist.
Types of Energy
Energy is the measurement of the amount of work that can be attributed to a force. It can also be defined as something that causes change or does work. There are several types or forms of energy. These types are mechanical, thermal (heat), electrical, nuclear, chemical, gravitational, etc. All these types of energy can cause change. Even the smallest changes that we often take for granted use energy, things like clicking the button on your computer mouse.
All forms of energy also has the ability to be transformed into another form. In our universe, energy cannot be created or destroyed, only transformed. This means that there is a specific or total amount of energy that is contained in our universe that is constantly being transformed from one form to another. For example, you can take light energy from the sun and transfer it into chemical energy trapped in the glucose within the leaves of a plant.
Thermal energy, or heat energy is a type of energy that measures how active the atoms or molecules in a given object or substance is. An object is hot when the atoms or molecules are moving rapidly. An object is cool when the atoms or molecules are not as active or are exhibiting less movement. For example, a glass of water at room temperature is relatively cool, the molecules are not moving too rapidly. If you boil the glass of water, the molecules begin to react, and you can see it as the water bubbles. This is because of heat energy.
When a hot object and a cool object come into contact, the hotter object transfers heat towards the cooler object till they reach a point of thermal equilibrium, or are of equal heat. For example, if you take a cube of ice out of the freezer, it begins to melt. This is because the ice is absorbing some of the heat from the air. Once the ice is fully melted, the water left behind by the ice will further heat up till it's more or less the same temperature as the air. They have reached thermal equilibrium.
Thermal energy can heat up a solid object causing it to melt, like ice or rocks. It can heat a liquid, causing it to evaporate, like water into the atmosphere. And it can drive air molecules away from each other. In all situations, heat breaks down a substance or an object's molecules, driving them further away from each other as they become more and more excited or active.
Next Article: Demonstrating Heat Energy
