Table of contents:
- 1. Digital thermometer
- 2. Infrared thermometer
- 3. Mercury or glass thermometer
- What temperature is fever
- How to use the thermometer on the baby

Thermometers vary according to the way of reading the temperature, which can be digital or analog, and with the place of the body most suitable for its use, there are models that can be used in the armpit, in the ear, forehead, mouth or anus.
The thermometer is important to check the temperature whenever there is a suspicion of fever or to control the improvement or worsening of infections, especially in children.
It is important that the thermometer is properly sanitized after each use, especially digital thermometers, mercury and infrared ear thermometers, as they come in direct contact with the skin.
1. Digital thermometer

To measure the temperature with the digital thermometer, follow these steps:
- Turn on the thermometer and check if the number zero or just the "ºC" symbol appears on the screen;
- Place the thermometer tip under the armpit or carefully insert it into the anus, especially for taking children's temperature. In the case of measurement in the anus, one should be lying with the tummy up and introduce only the metallic part of the thermometer into the anus;
- Wait a few seconds until you hear a beep;
- Remove the thermometer and check the temperature value on the screen;
- Clean the metallic tip with cotton wool or gauze moistened with alcohol.
See some precautions to measure the temperature correctly and understand what temperature is considered normal.
2. Infrared thermometer

The infrared thermometer reads the temperature through rays that are emitted to the skin, but that do not harm he alth. There are infrared ear and forehead thermometers and both types are very practical, fast and hygienic.
In the ear:
To use the ear thermometer, also known as a tympanic or ear thermometer, you must:
- Place the thermometer tip inside the ear and point it towards the nose;
- Press the power button on the thermometer until you hear a beep;
- Read the temperature value, which appears at the time;
- Remove the thermometer from the ear and clean the tip with cotton wool or alcohol gauze.
The infrared ear thermometer is very fast and easy to read, but requires regular purchase of protective plastic caps which make the thermometer more expensive to use.
On the forehead:
Depending on the type of infrared forehead thermometer, it is possible to measure the temperature by placing the device directly in contact with the skin or at a distance of up to 5 cm from the forehead. To use this type of device correctly, you must:
- Turn on the thermometer and check that the number zero appears on the screen;
- Place the thermometer on the forehead above the eyebrow, in case the thermometer instructions recommend skin contact, or point the thermometer towards the center of the forehead;
- Read the temperature value that comes out immediately and remove the thermometer from your forehead.
In cases where the instructions recommend touching the device to the skin, clean the tip of the thermometer with cotton wool or gauze with alcohol after use.
3. Mercury or glass thermometer

The use of mercury thermometer is contraindicated due to he alth risks such as respiratory problems or skin damage, but nowadays there are also glass thermometers similar to the old mercury ones, called analog thermometers, which do not have mercury in your composition and that can be used safely.
To measure the temperature with these devices, you must:
- Check the temperature of the thermometer before using it, noting if the liquid is close to the lowest temperature;
- Place the metallic tip of the thermometer under the armpit or in the anus, according to the place where the temperature is to be measured;
- Keep the arm that has the thermometer still close to the body;
- Wait 5 minutes and remove the armpit thermometer;
- Check the temperature, observing the place where the liquid ends, which will be the value of the measured temperature.
This type of thermometer takes longer to measure the temperature than others, in addition to being more difficult to read, especially for elderly people or people with vision problems.
How to clean a broken mercury thermometer
In case of breaking a thermometer with mercury, it is very important to avoid any type of direct contact with the skin. Thus, initially you should open the window of the room and leave the room for at least 15 minutes. Afterwards, put on rubber gloves and, to gather the various mercury pellets, it is advisable to use a piece of cardboard and aspirate the mercury with a syringe.
At the end, to ensure that all the mercury has been collected, darken the room and use a flashlight to illuminate the area where the thermometer broke. If you can spot something glowing, it's possible it's a stray mercury pellet.
If the mercury comes into contact with absorbable surfaces, such as rugs, clothes or towels, when broken, it should be thrown away, as there is a risk of being contaminated. All material used in cleaning or that is discarded must be placed in a plastic bag and then left at an appropriate recycling center.
What temperature is fever
The temperature indicative of fever may vary according to the place where the measurement is taken, that is, whether in the armpit, ear, forehead, mouth or anus. The following table provides information on which temperature is considered a fever according to body location:
Body location | Fever temperature |
---|---|
Axilla | Above 37.6ºC |
Ânus | Above 38ºC |
Mouth | Above 37.5ºC |
Heard | Above 37.8ºC |
On the forehead | Above 37.8ºC for children aged 4 and over |
How to use the thermometer on the baby
To measure the baby's temperature, all types of thermometers can be used, but it is easier to measure the temperature with thermometers that are quick and do not cause discomfort to the baby, such as the infrared ear thermometer, the infrared thermometer forehead or digital thermometer.
Besides these, there is also the pacifier thermometer, which is very fast and comfortable, and which should be used as follows:
- Introduce the thermometer into the baby's mouth for 1 to 2 minutes;
- Read the temperature on the pacifier screen;
- Remove the pacifier and wash with warm water.
It is important to remember that to use any type of thermometer on the baby, keep him/her still so that the temperature value is as correct as possible.