The Sun's Energy and Hydrologic Cycle

The Sun

• It is the source of energy for the solar system.
• The energy from it radiates throughout the solar system by electromagnetic waves through the atmosphere.
• Some waves are blocked, but others reach the Earth's surface.
• The energy is transformed into thermal energy, which warms the air closest to the surface which is known as convection.
• Approximately 20% of the Sun's energy gets absorbed by ozone, clouds, and atmospheric gases.
• About 5% of the Sun's energy is reflected by Earth's surface.
• Roughly 50% of the Sun's energy is absorbed by Earth's surface.
• Around 25% of the Sun's energy is scattered and reflected by clouds and air.

The Water Cycle (Hydrologic Cycle)

• The Sun's energy drives the movement of water around the planet and throughout the atmosphere.
• Water changes forms as it moves through the cycle by gaining and losing energy.
• Water in lakes and oceans gains energy and evaporates into the atmosphere as water vapor.
• As water vapor rises, it loses energy and condenses back into liquid particles, forming clouds.
• Condensed particles join together to create larger, heavier liquid drops that fall as precipitation due to gravity.
• Processes like condensation and evaporation involve water changing from a liquid to a gas.
• Snow and ice can also change from a solid to a gas through sublimation.
• Precipitation can follow various pathways depending on the surface, including seeping into the ground as groundwater or being stored in aquifers.
• It can also run off into larger bodies of water.
• Water returns to streams, rivers, ponds, lakes, and oceans through accumulation.
• Water can re-enter the atmosphere through evaporation from the ground and transpiration from living organisms.
• Living organisms contribute water to the atmosphere in vapor form through respiration.
• All the water on the planet is cycled and exists in different forms.

Factors Influencing Earth's Weather

• The position, shape, and tilt of Earth, along with its atmosphere, differentiate weather from other planets.
• The atmosphere circulates water.
• Gases needed for life are held in predictable amounts.
• The atmosphere protects from ultraviolet radiation.
• It moderates temperatures.
• It prevents extreme storms.

Thermal Energy Transfer

• The Sun's energy reaches Earth through radiation, traveling in electromagnetic waves.
• All objects can take in and emit radiation
• The Sun is main source of thermal energy.
• When energy reaches the Earth, a portion is absorbed by the surface.
• It warms the planet or radiates back into space.
• Heat is transferred through conduction, requiring direct physical contact between particles.
• Molecules surrounding the Earth's surface receive heat from the heated surface.
• Convection occurs as warm air masses expand, rise, and are replaced by cooler, denser air.
• Convection creates currents in the atmosphere and oceans and happens in both gases and liquids (fluids).

Heat Absorption and Release Rate Experiment

• The lab showed how different materials absorb and release heat at different rates.
• Water, sand, and soil were tested with controlled factors like sunlight angle, surface area, and thermometer placement.
• Water did not gain as much heat energy as soil or sand and did not lose as much heat when removed from the lamp's heat.

Uneven Heating of Land and Sea

• Land heats up and cools down faster than oceans due to water's higher heat capacity.
• Water's high heat capacity leads to smaller temperature fluctuations and allows it to absorb and distribute heat more effectively.
• Coastal communities are warmer in the winter because water holds onto heat for longer.
• Land experiences rapid temperature changes, leading to phenomena like sea breezes, where cooler air moves from the ocean to warmer land.