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Thermometer Definition

A thermometer measures a substance's temperature by its particles' speed. For example, it indicates how hot or cold water is.

View Lesson on Intro to Thermal Energy
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Intro to Thermal Energy

Fun Facts

  • A thermometer measures an average temperature because the particles within a substance do not all move at exactly the same speed.
  • A thermometer shows that the temperature of ice is 0 degrees Celsius, the temperature of steam is 100 degrees Celsius, and the temperature of liquid water is in between.
  • A surface thermometer uses an infrared or liquid crystal strip.

Why Do We Need To Know About Thermometer

Learning about thermal energy helps you understand how heat changes things and why thermometers are important in many areas. For example, in cooking, knowing the right temperature makes sure food is safe and tastes good. This is important for baking cookies or heating food in microwaves.

Thermometers are also key in different jobs like environmental engineering, the military, and healthcare. They help in making fake snow, heating ready-to-eat meals, or using cold packs in sports. So, measuring and managing heat is useful in lots of careers and everyday life.

Frequently Asked Questions

Why do hot objects have high temperatures?
Temperature measures the average kinetic energy of the atoms or molecules that make up an object. As thermal energy is added to an object, the object’s molecules move faster. When the molecules move faster, they have more kinetic energy. So the temperature increases.
What happens to the molecules that make up a chocolate chip as it is heated in the oven?
As thermal energy is transferred to the chocolate, its molecules vibrate faster and faster. Eventually they vibrate fast enough that they start to slide past each other and move around. As this happens, the chocolate changes from a solid to a liquid.
Why do water droplets form on the outside of a glass of cold soda?
Thermal energy moves from water vapor in the air around the glass into the cold drink. As the water molecules in the air lose energy, they slow down and move closer together. As this happens, the water vapor condenses into a liquid on the outside of the glass.
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