Science Behind It: How Do Thermometers Measure Temperature?

Have you ever put a thermometer under your tongue and wondered how that little device knows if you have a fever? Or did the weather be checked and considered how scientists measure temperature so accurately? The answer lies in some interesting science.

Thermometer works by detecting changes in heat. Heat can cause substances to expand, alter electrical properties or emit invisible radiation – which can be measured and converted to temperature readings. Whether it is a traditional mercury thermometer, a modern digital thermometer, or a high-tech infrared scanner, they all rely on the same rationale: heat affects substances in a predictable way, and we can use these changes to measure temperature.

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Let’s break it down and explore how different thermometers work.

What is temperature?

Before digging into how the thermometer works, let’s first understand what temperature is actually.

Temperature is more than just feeling cold or cold – it is a measure of the speed of tiny particles (atoms and molecules) in a matter. When the substance heats up, these particles move faster. When it cools, they slow down.

Think of it as boiling water: When the water is cold, the molecules move slowly. As the heat is done, the molecules begin to bounce faster and faster until the water starts to boil. This movement of molecules is measured in different ways by the thermometer.

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How do different thermometers measure temperature?

There is not only a way to measure temperature. Over time, scientists have developed several types of thermometers based on different scientific principles. Let’s explore some of the most common ones.

Mercury thermometer

A classic thermometer with thin glass tubes and red or silver liquid inside is called a glass liquid thermometer. These use the principle of thermal expansion – the idea of ​​substances expanding when heated and shrinking when cooled.

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The thermometer’s small bulb is filled with mercury (in older thermometers) or alcohol (modern thermometers).

As the temperature rises, the liquid expands and moves upwards the narrow tube.

As the temperature drops, the liquid shrinks and moves downward.

The temperature scale on the glass tube shows readings of degrees Celsius (°C) or degrees Fahrenheit (°F).

Because mercury is toxic, most modern thermometers use alcohol, which is dyed red or blue for easier visibility. These thermometers are ideal for measuring body temperature, room temperature and even weather conditions.

Digital thermometer

Digital thermometers are faster and more accurate than traditional thermometers. They work using electronic components called thermistors, which change their resistance to electricity as temperature changes.

The thermistor inside the thermometer can detect how much power can pass.

As the temperature rises, the resistance changes.

The microcomputer inside the thermometer calculates the temperature based on this resistance and displays it on the screen.

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The method is highly accurate and fast, which is why digital thermometers are commonly used in medical, cooking and environmental monitoring.

Infrared thermometer

Have you ever seen a thermometer that can check your body temperature without touching your That’s an infrared thermometer. Instead of measuring expansion or resistance, it detects infrared radiation (thermal energy) emitted by all objects.

Each object emits infrared radiation – hot girl object emits more. The thermometer has a special sensor that can pick up this radiation. The sensor converts infrared energy into temperature readings.

This is why infrared thermometers are used for fever screening, food safety and industrial applications, and they can measure temperatures from a distance immediately.

Bimetallic band thermometer

Another fascinating type of thermometer is the bimetallic zone thermometer, which expands at different speeds when heated by using two different metals.

Two metals (such as iron and brass) are connected together on strips. When the temperature rises, one metal expands over the other, causing the strip to bend. This bending movement moves a needle on the dial to display the temperature.

These thermometers are often found in oven dials, refrigerators and industrial machines.

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in conclusion

From simple glass tubes to high-tech digital and infrared devices, thermometers have come a long way. Today, we even have smart thermometers connected to mobile apps, wearable wearable sensors, and advanced space thermometers that measure the temperatures of stars and planets, which are millions of miles. So the next time you check your temperature or check your weather forecast, remember the incredible science behind this gadget! This is the science today.

Source: https://dinhtienhoang.edu.vn
Category: Optical Illusion