There are two standard units used for measuring temperature, viz. Celsius and Fahrenheit. When we think of a thermometer, a mercury-filled glass tube comes to our mind. Galileo invented a basic thermometer in 1593, but it was not approved for many years. Later on, Gabriel Fahrenheit invented the mercury-filled thermometer. Along with mercury, alcohol was also used earlier to measure temperature in a thermometer. Today, there are different kinds of thermometers. Let us discuss different types of thermometers.
Measurement Units of Different Thermometer Types
Celsius and Fahrenheit Thermometers
The Celsius thermometers use the Celsius (°C) as the measurement unit and Fahrenheit thermometers use Fahrenheit (°F) as the temperature measurement unit. Some thermometers have the measuring scales for both Celsius and Fahrenheit. These thermometers give the reading in Celsius as well as Fahrenheit.
Applications of Different Thermometers
Clinical Thermometers
The clinical thermometers are used to measure the body temperature of the patient. There are again three types of clinical thermometers depending on the body part used to measure the temperature.
Ear (Tympanic) thermometers
Human ear is located near the brain. This makes it an accurate point to measure the body temperature. The temperature of the eardrum is measured by the ear thermometers. However, the eardrum is most fragile and delicate body part. Therefore, the body temperature cannot be measured by touching the eardrum. For temperature measurement, infrared sensors are used to remotely sense the temperature of the eardrum. Thermopile, an infrared sensor, is commonly used in ear thermometer.
Pacifier Thermometers
The pacifier thermometers are used to check the body temperature of babies or infants. They help measure the body temperature without irritating the baby. The thermometer is held in the mouth of the baby and the baby's natural sucking instinct is used to check its body temperature. The pacifier thermometers are very safe for checking the body temperature of babies.
Underarm or Oral Thermometers
The underarm thermometers are kept in the underarms to measure the body temperature of the patient. Likewise, the oral thermometers are held in the mouth for temperature measurement.
Food Thermometers
There are many food thermometers like the dial oven-safe thermometers, digital instant thermometers, pop-up thermometers and disposable thermometers. The dial oven-safe thermometers are used for thick foods and can be placed in the food while you are cooking the food. However, the dial oven-safe thermometers are not suitable for thin and watery foodstuffs. The digital instant thermometers cannot be kept in the food while cooking. These thermometers read the temperature within 10 seconds. The pop-up thermometers are used to measure the temperatures of turkey and chicken. The disposable thermometer strips are used to measure the temperature of food after they are cooked and they change the color according to the temperature. The color of these thermometer strips can be matched to a chart, which gives the corresponding temperature of food.
Outdoor Thermometers
The outdoor thermometers are used to measure the temperature of the surrounding air. Wireless outdoor thermometers are very popular these days.
Mechanism of Different Types of Thermometers
Mercury and Alcohol Thermometers
Mercury thermometers have mercury filled in a glass tube and has a glass bulb at the bottom. As the temperature increases, the mercury rises in the glass tube. The glass tube is calibrated in Celsius, Fahrenheit or both. The rise in mercury determines the temperature according to the calibration. Alcohol thermometers have ethanol or toluene instead of mercury in the glass tube. All the other mechanism of the thermometer are same as that of the mercury thermometer. They are used as clinical thermometers and outdoor thermometers.
Digital Thermometers
Digital thermometers use thermocouples or thermistors to sense the change in temperature and display the temperature on a digital display. They are widely used as clinical, outdoor and food thermometers. Infrared thermometers use the infrared sensors to determine the temperature and have a digital display.
Measurement Units of Different Thermometer Types
Celsius and Fahrenheit Thermometers
The Celsius thermometers use the Celsius (°C) as the measurement unit and Fahrenheit thermometers use Fahrenheit (°F) as the temperature measurement unit. Some thermometers have the measuring scales for both Celsius and Fahrenheit. These thermometers give the reading in Celsius as well as Fahrenheit.
Applications of Different Thermometers
Clinical Thermometers
The clinical thermometers are used to measure the body temperature of the patient. There are again three types of clinical thermometers depending on the body part used to measure the temperature.
Ear (Tympanic) thermometers
Human ear is located near the brain. This makes it an accurate point to measure the body temperature. The temperature of the eardrum is measured by the ear thermometers. However, the eardrum is most fragile and delicate body part. Therefore, the body temperature cannot be measured by touching the eardrum. For temperature measurement, infrared sensors are used to remotely sense the temperature of the eardrum. Thermopile, an infrared sensor, is commonly used in ear thermometer.
Pacifier Thermometers
The pacifier thermometers are used to check the body temperature of babies or infants. They help measure the body temperature without irritating the baby. The thermometer is held in the mouth of the baby and the baby's natural sucking instinct is used to check its body temperature. The pacifier thermometers are very safe for checking the body temperature of babies.
Underarm or Oral Thermometers
The underarm thermometers are kept in the underarms to measure the body temperature of the patient. Likewise, the oral thermometers are held in the mouth for temperature measurement.
Food Thermometers
There are many food thermometers like the dial oven-safe thermometers, digital instant thermometers, pop-up thermometers and disposable thermometers. The dial oven-safe thermometers are used for thick foods and can be placed in the food while you are cooking the food. However, the dial oven-safe thermometers are not suitable for thin and watery foodstuffs. The digital instant thermometers cannot be kept in the food while cooking. These thermometers read the temperature within 10 seconds. The pop-up thermometers are used to measure the temperatures of turkey and chicken. The disposable thermometer strips are used to measure the temperature of food after they are cooked and they change the color according to the temperature. The color of these thermometer strips can be matched to a chart, which gives the corresponding temperature of food.
Outdoor Thermometers
The outdoor thermometers are used to measure the temperature of the surrounding air. Wireless outdoor thermometers are very popular these days.
Mechanism of Different Types of Thermometers
Mercury and Alcohol Thermometers
Mercury thermometers have mercury filled in a glass tube and has a glass bulb at the bottom. As the temperature increases, the mercury rises in the glass tube. The glass tube is calibrated in Celsius, Fahrenheit or both. The rise in mercury determines the temperature according to the calibration. Alcohol thermometers have ethanol or toluene instead of mercury in the glass tube. All the other mechanism of the thermometer are same as that of the mercury thermometer. They are used as clinical thermometers and outdoor thermometers.
Digital Thermometers
Digital thermometers use thermocouples or thermistors to sense the change in temperature and display the temperature on a digital display. They are widely used as clinical, outdoor and food thermometers. Infrared thermometers use the infrared sensors to determine the temperature and have a digital display.