Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound. Ultrasound can be used for measuring wind speed and direction (anemometer), tank or channel fluid level, and speed through air or water.
A teacher, also called a schoolteacher or formally an educator, is a person who helps students to acquire knowledge, competence, or virtue, via the practice of teaching. Informally the role of teacher may be taken on by anyone (e.g. when showing a colleague how to perform a specific task). In some countries, teaching young people of school age may be carried out in an informal setting, such as within the family (homeschooling), rather than in a formal setting such as a school or college.
Teacher education or teacher training refers to programs, policies, procedures, and provision designed to equip (prospective) teachers with the knowledge, attitudes, behaviors, approaches, methodologies and skills they require to perform their tasks effectively in the classroom, school, and wider community. The professionals who engage in training the prospective teachers are called teacher educators (or, in some contexts, teacher trainers). There is a longstanding and ongoing debate about the most appropriate term to describe these activities.
A student teacher or prac teacher (practice teacher) is a college, university or graduate student who is teaching under the supervision of a certified teacher in order to qualify for a degree in education. The term is also often used interchangeably with pre-service teacher. It is a much broader term to include those students that are studying the required coursework in pedagogy, as well as their specialty, but have not entered the supervised teaching portion of their training.
A certified teacher is an educator who has earned credentials from an authoritative source, such as the government, a higher education institution or a private body or source. This teacher qualification gives a teacher authorization to teach and grade in pre-schools, primary or secondary education in countries, schools, content areas or curricula where authorization is required. While many authorizing entities require student teaching experience before earning teacher certification, routes vary from country to country.
