The Sun and Water Cycle Overview

Here is an overview of our unit so you know how to review it with your child at home! 
 
Students had prior experience with the water cycle in second grade. They explored the processes in the water cycle, including evaporation, condensation, and precipitation, as connected to weather conditions. Third grade students will extend that understanding by exploring how the properties of the Sun impact the water cycle on Earth.

Key Concept 1: The Sun, like all stars, is made up of gases. Stars are enormous balls of gas in space that produce their own light and heat.

Our Sun is a star that sits at the center of our Solar System. Stars vary in size, color, and temperature. Although the Sun is over a million times larger than Earth, in comparison to billions of other stars, it is only average size and average temperature. Our yellow star provides just the right amount of heat and light to allow water to flow and life to flourish.

Key Concept 2: The Sun produces light and heat energy.

The light and heat energy that a star produces comes from the tremendous mass of gases crushing the inside of the star. Inside the Suns core, hydrogen gas fuses into helium gas, which gives off light and heat energy that radiates throughout the Solar System. Earth, as the third planet from the Sun, orbits at just the right distance so that water can exist as a solid, a liquid, and as a gas (water vapor).

The Sun also produces bursts of energy originating from sunspots, which can produce solar flares. Incredibly hot gases on the surface of the Sun bubble up and down, which causes some areas on to be cooler than others, producing dark areas called sunspots that can last weeks or months. The magnetic fields around a sunspot sometimes become really twisted. Those twisted magnetic field lines can snap and explode to produce a solar flare that releases huge amounts of energy.

Key Concept 3: The Sun is the source of energy for the water cycle.

The Suns energy powers the water cycle, which is the change to water as it moves up into the air and then back down to Earths surface. The heat energy from the Sun raises the temperature of the surface water in oceans, lakes, rivers, and streams causing some water molecules to move fast enough to break loose and escape into the air. This activity begins the process of evaporation where liquid water turns into a gas called water vapor. Because the Sun heats Earth unevenly, winds form and move the air mass with the water vapor to another location. As the water vapor continues to rise, cooler temperatures cause condensation (gaseous water vapor changes back to liquid water droplets, just like drops of water on a cold soda can). This condensation takes the form of clouds that can become too saturated with the water droplets and precipitation begins (Rain, snow, sleet, or hail falls from clouds in the sky.). Once the precipitation is on the ground, the water either soaks into the ground to eventually become groundwater (underground streams and lakes) or runoff that drains into lakes, streams, and rivers, which flow back into Earths oceans, and the water cycle begins again.