Year

A year is a unit of time that is based on the Earth's orbit around the sun. It is the time it takes for the Earth to complete one full orbit around the sun. The concept of a year is important in understanding seasons, climate, and the passage of time.

Key Facts about a Year:

1. The Earth takes approximately 365.25 days to orbit the sun once.

2. To account for the extra .25 days, we add an extra day to the calendar every four years. This is called a leap year, and February 29th is added to the calendar.

3. The Earth's orbit around the sun is not a perfect circle, but rather an ellipse. This means that the Earth is sometimes closer to the sun (perihelion) and sometimes farther away (aphelion) during its orbit.

4. The time it takes for the Earth to complete one orbit around the sun is called a tropical year and is used in the Gregorian calendar, which is the most widely used calendar system today.

Study Guide:

1. What is a year and what is it based on?
2. How long does it take for the Earth to orbit the sun once?
3. What is a leap year and why is it necessary?
4. Explain the difference between perihelion and aphelion.
5. What is the Gregorian calendar and how is it related to a year?