Physical Science:

The regular rise and fall of ocean water is called tides. Tides are water waves that occur naturally in ocean due to force of gravity on earth surface due to the moon and the sun. Please watch this video to understand the tides. Tide Formation

³

astro.unl.edu/classaction/animations/lunarcycles/tidesim.html

Because of moon’s gravity water bulges out of the earth surface and keep getting dragged as the moon moves around the earth. The effect of moon’s gravity is more on the earth surface than the sun’s gravity due to their distant positions. When sun and moon are located along the same direction high tide is higher than normal high tide and low tide is lower than normal low tide and they are collectivly called Spring Tide. When sun and moon are at right angles to each other than high tide and low tide both are shorter than usual and they are called Neep Tide. There are alawyes two high and two low tides in every 24 hours.

Please observe the link: Celestial Sphere

⁴

astro.unl.edu/classaction/animations/coordsmotion/sunmotions.html

The yellow circle in the animation is called an Ecliptic line. It is an apparent path of the sun in the sky as viewed from the earth over the course of a year.