A thermometer is a simple device used to measure temperature. It can tell us how hot or cold something is, whether it's the weather outside or the temperature of a cup of hot chocolate. Most thermometers have a scale marked in degrees, which helps us understand the temperature reading easily. There are different types of thermometers, including digital and mercury ones. Digital thermometers provide quick readings and are often used in homes and hospitals. On the other hand, mercury thermometers use liquid mercury to show temperature changes. Both types help us stay safe and healthy by monitoring temperatures accurately.