Investigating An Ecosystem: The Seashore
Part 2

 During our visit to Island Beach, we collected rocks. During the last month of school we will use the above tests to test the rocks. The fourth-grade students used the Insights kit "Changes of State" to investigate the changes that occur during the water cycle.They participated in experiments involving melting, evaporation, condensation and freezing. Their first experience involved designing an experiment around melting ice. Each group brainstormed ways to melt ice quickly and then designed an experiment to test two of the methods. Here is Adrienne Atkinson's (201) experment. Question: Which method will make ice melt more quickly, putting it in your mouth or using a blow dryer? Hypothesis: Putting ice in your mouth will make the ice melt more quickly than using a blow dryer. Materials: two ice cubes, napkins, clock, blow dryer, plastic bag, pencil, notebook Procedure: 1. Put ice cube #1 in the bag. 2. Put ice cube #2 in your mouth. 3. Aim the blow dryer on the ice cube. 4. Time to see which will melt faster. Results: The ice in Lataya's mouth melted in 3 minutes. The ice in the bag in front of the blow dryer melted in 4.5 minutes. Conclusion: My hypothesis was supported. The ice in Lataya's mouth melted faster than the ice in front of the blow dryer. One evaporation experiment tested "How does the amount of surface area that is exposed to the air affect the rate of evaporation ?" Here is Simon Wiliford's (201) experiment. Question: On which square of newsprint will alcohol evaporate the fastest? Hypothesis: Number 2 (flat square) is going to evaporate the fastest. Materials: tray, squeeze bottle of alcohol, 4 newsprint squares, pencil, notebook, clock Procedure: 1. Number the squares. 2. Leave #1 flat. 3. Fold #2 in half. 4. Fold #3 in fourths. 5. Crumple #4. 6. Put a drop of alcohol on each square. 7. Time them. Results: Square #1 evaporated in 6 minutes and 8 seconds. Square #2 evaporated in 2 minutes. Square #3 evaporated in 4 minutes and 50 seconds. Square #4 evaporated in 6 minutes and 51 seconds. Conclusion: My hypothesis was supported. Square #2 evaporated faster than 1,3, and 4 because it was flat. The students set up a demonstration of condensation. They filled a metal can half way with colored water and added ice. They observed the outside of the can before and after the ice was added. Here is Tyreek Dorsey's (201) report. Question: What changes will occur on the outside of a can of water if ice is added to the can? Hypothesis: The can will have water on the outside. Observation: Before adding ice - The can was very cold. After adding ice - After 5 minutes the can got very, very cold. I saw water on the outside of the can. Conclusion: My hypothesis was supported. The last process that we investigated was freezing. They set up an experiment to see how the amount of water affects the rate of freezing. The children used crushed ice, rock salt and styrofoam cups to make mini-freezers. They placed 1/8 ounce of water and 1/4 ounce of water in small cups and placed them in the mini-freezers. Please read Justin Wilson's (201) observations that were written during the experiment. The temperature of the ice is -5­C. The temperature of the ice and salt is -15­ C. After 5 minutes there is a little bit of ice in the cup with 1/8 ounce of water. The cup with 1/4 ounce is still all water. After 10 minutes the 1/8 ounce of water is frozen. There's water and ice in the 1/4 ounce cup. After 15 minutes the 1/8 ounce of water is completely frozen. There's a lot of ice and a little bit of water. After 20 minutes the cup with 1/4 ounce of water had a little drop of water and a lot of ice. 1/8 ounce froze more quickly than 1/4 ounce. Cinquetta Alston (201) defined the above processes. Solids melt when they change to the liquid state. Liquids freeze when they change to the solid state. The change from a liquid to a gas is called evaporation. The change from a gas to a liquid is called condensation. The final demonstration was a model of the entire water cycle: evaporation, condensation and precipitation. The children learned that water in oceans, rivers, lakes, etc. evaporates from the heat of the sun. Tiny drops of water called water vapor are carried up by warm rising air. When the vapor hits the high cool air, it turns back to water drops that form clouds. (condensation). The water falls to earth as rain, snow, sleet and hail (precipitation). The water returns to the oceans, rivers and lakes and the cycle starts again.

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