4 th Grade Earth Science Weeks 1 & 2 Effects of Sun on Earth

The sun is a star. Our solar system has only one star. Sun close-up. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming:

The outer visible layer of the sun has a temperature of 6,000°C (11,000°F). Its light and heat travels through space to the earth. news/0003/02sunwarming

The Sun is the major driving force behind weather on our planet. Sun over water. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming:

When the sun heats water, the water begins to evaporate. Approximately 80% of all evaporation is from the oceans, with the remaining 20% coming from inland water and vegetation.

Because Earth is tilted on its axis, it does not get direct sunlight everywhere on its surface.

The sun’s heat warms the air. Warm air rises, and cool air sinks.

Because the earth spins (rotates) on its axis, the paths of winds bend clockwise north of the equator. Hurricanes spin clockwise in the northern hemisphere.

Conditions of the earth's atmosphere at a given place and time are called weather. Some of these conditions are: Temperature Wind speed Precipitation Humidity Cloud cover

Temperature The measure of how much heat an object has. Heat is how much molecules in an object vibrate. The faster the molecules vibrate, the hotter the object is.

Temperature In America we use the Fahrenheit and Celsius scales for measuring temperature. Celsius is the temperature scale that is used in science. FahrenheitCelsiusImage from Pearson Prentice Hall, Inc. (2005)

Wind Speed The speed of the wind and the direction it is coming from are important for predicting weather. Generally, fast winds coming from the north indicate a cold front. Anemometers measure wind speed. Wind vanes measure direction. Some anemometers can do both. Images From:

Precipitation Any form of water that falls from clouds is precipitation: Rain Rain Hail Hail Sleet Sleet Snow Snow Precipitation, illustration. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming:

Humidity Foggy days are very humid. There is a lot of humidity in the Houston area each summer. Humidity, definition. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming:

Cloud Cover The weather forecast usually includes the cloud cover. This is the amount of the sky that is covered with clouds. Stratocumulus clouds. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming: Mostly cloudy, or overcast.

The Water Cycle The process that water goes through from evaporation through precipitation. Water cycle. Paul Fuqua. (2005). Retrieved February 14, 2006, from unitedstreaming: precipitation evaporation condensation

Seasonal Patterns What can you conclude from this chart of Houston’s average temperatures and rainfall? Houston JanFebMarAprMayJuneJulyAugSeptOctNovDec Avg High ◦F Avg Low ◦F Avg Rain inches Avg Wind mph T-storm Days