|Earth and Space Science||Structure of the Earth 7I3.00||Process Of Science||Explaining1.5 a|
Sponsored by the National Science Foundation
CONTENT STANDARD: Earth and Space Science
CONTENT TOPIC: Structure of the Earth
CONCEPT: There is a continuous movement of water from earth to air to earth.
CONTENT OBJECTIVE: 7I3.00 To understand the water cycle
INSTRUCTIONAL OBJECTIVE: The learner will:
TN COMPONENT OF SCIENCE: Process of Science
BENCHMARK: The graphic display of numbers may help to show patterns such as trends, varying rates of change, gaps, or clusters.
Water is the main substance that covers our earth. Only three percent of this water is fresh water that we are able to drink. (Demonstration on the usable fresh water.) Water is not made or destroyed, so you could say that water is a "recyclable product." The water cycle is a continuous movement of water between the earth and air. As the water cycle occurs, water passes through all three of its phases: solid, liquid, and gas. Water is gathered on the earth's surface in two primary ways. One way is it can be found in lakes, rivers, and streams. As water leaves the lakes, rivers, and oceans and enters the atmosphere, the water changes from a liquid to a gas. This process is called evaporation. The other way liquid is stored on the earth's surface is in plants. As the water leaves the plant through its leaves, the water again converts from liquid to gas, but this time it is called transpiration. (Demonstration of transpiration). In the atmosphere, the gas converts back to a liquid. When a large amount of the liquid builds up in the atmosphere, the liquid falls back to the earth as precipitation. The main form of precipitation is rain, but if the temperature is cold enough, we will get the precipitation in the from of snow. (Do activity of observing the phases of water.)
Once the precipitation reaches the earth, it can sink into the ground, which is known as ground water. The water that does not sink is called surface water and it usually runs into lakes, rivers, and oceans. The ground water is used by the plants and keeps circulating through the water cycle as it becomes a gas again through transpiration. Surface water simply evaporates and keeps going through the water cycle.
2. Transpiration: Take a healthy, well-watered plant and cover it with a plastic bag. Place the plant in a window for approximately 30 minutes. Observe the bag and the drops of water that cover its inside. These drops of water are a direct result of transpiration.
3. Observing the Phases of Water: Fill the drinking glass half full with the hot water. Place a piece of plastic wrap tightly over the opening. Place 5 or 6 ice cubes on top of the wrap and allow it to sit for about 5 minutes. Record all observations. After the 5 minutes, pick up the plastic wrap and feel the side that covered the glass.
Graphs can be used to help convey information in an easier form. Look at the following sets of data concerning the earth's water supply. Use this information to complete the following graphs.
||Percentage of total|
|Water in Atmosphere|
|Ground water within a half mile of surface|
|Deep-lying ground water|
evaporation - the process by which liquid water changes to water vapor.
transpiration - the process by which plants release water vapor into the atmosphere through their leaves.
precipitation - how the water returns to the earth and is found in many different forms: rain, snow, sleet, and hail.
ground water - the water that sinks into the ground after it is precipitated
surface water - water that flows into the rivers, lakes, and oceans
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