SEASONS OF THE EARTH SEASONS OF THE PHILIPPINES SCIENCE 7 QUARTER 4 WEEK 4 WEEK 5

Understanding Seasons: How Do They Occur?

Introduction to Seasons

• The video introduces the concept of seasons and poses a question about why different countries experience varying seasonal patterns, specifically contrasting the Philippines' wet and dry seasons with other regions that have four distinct seasons.

Definition of Seasons

• Seasons are defined as periods within a year characterized by specific weather and climate conditions. The four main seasons are spring, summer, autumn, and winter, each differing in sunlight exposure, temperature, and weather patterns.

Earth's Rotation and Revolution

• The Earth rotates around an imaginary axis that runs from the North Pole to the South Pole. This rotation takes 24 hours (one day), resulting in alternating daytime and nighttime across the planet.

• In addition to rotation, Earth revolves around the sun over approximately 365.25 days (one year). This movement is crucial for understanding seasonal changes.

Tilt of Earth's Axis

• The Earth's axis is tilted at an angle of 23.5 degrees. This tilt causes different parts of the Earth to receive varying amounts of sunlight throughout its revolution around the sun.

• Areas receiving more solar rays experience warmer temperatures while those receiving less experience cooler temperatures.

Solstices and Equinoxes

• Key astronomical events include solstices—marking unequal lengths of day and night—and equinoxes—when day and night durations are nearly equal.

• Summer solstice occurs on June 21 or 22; winter solstice on December 21 or 22.

• Vernal equinox on March 21 or 22 marks spring in the northern hemisphere; autumnal equinox on September 21 or 22 marks autumn in the north.

Seasonal Variations Across Hemispheres

• During June, when the Northern Hemisphere tilts toward the sun, it experiences longer days leading to warmer temperatures (summer).

• Conversely, during this time, countries in the Southern Hemisphere receive less direct sunlight resulting in colder temperatures (winter).

Climate Patterns in Tropical Regions

• By December, as Earth moves to another side of the sun, Northern Hemisphere countries face colder conditions while Southern Hemisphere countries enjoy summer due to their tilt towards the sun.

• The Philippines experiences only two seasons—wet (June to November) and dry (December to May)—due to its proximity to the equator where sunlight remains relatively constant throughout the year.

Conclusion on Seasonal Changes

• Seasonal changes result from Earth's axial tilt combined with its revolution around the sun affecting direct sunlight exposure.