3. Guess the word by the explanation of its meaning. 1) a device used in navigation that keeps steady because of a heavy
wheel spinning inside it
2) a period of hundred years

1) The device described here is a compass. A compass is a navigation tool used to determine direction. It consists of a magnetic needle that aligns itself with the Earth's magnetic field, allowing the user to identify the cardinal directions (north, south, east, and west). The explanation mentions a "heavy wheel spinning inside it," which refers to the magnetic needle contained within the compass. The spinning motion of the needle allows it to align with the Earth's magnetic field and point towards the North Pole.

2) The period of hundred years is called a century. A century is a unit of time that encompasses 100 years. It is often used to refer to significant historical periods or to categorize events or achievements that occurred over a span of 100 years. For example, the 20th century refers to the period from 1900 to 1999. The term century is derived from the Latin word "centum," meaning one hundred.