Fever thermometers keep track of body temperature and confirm your suspicions when the fever sets in. There are models that measure via the ear, forehead, orally, in the armpit and rectally. For children, the ear and forehead are the best options as they are the easiest. Water-resistant fever thermometers do not break in damp bathrooms and can be used in the shower. Automatic shutdown saves battery power and LCD screen facilitates settings.