Earth & Environmental Systems II Lab 1. Greenhouse Gases, Albedo and Temperature

Transcription

1 Earth & Environmental Systems II Lab 1 Name: Part 1 Greenhouse Gas and Temperature Greenhouse Gases, Albedo and Temperature Greenhouses gases, such as carbon dioxide (CO 2) absorb infrared (heat) radiation. This natural energy storage is responsible for making Earth a comfortable average 15⁰C. What happens when we add unnatural greenhouse gases into the atmosphere by burning fossil fuels? Well, a little can go a long way. We will do a simple exercise where we examine temperature change over a short period of time (30 minutes)with two bottles half filled with water. One bottle will contain ambient air and the other ambient and CO 2 compliments of alka seltzer. Materials: 2 plastic bottles half filled with water 2 rubber stoppers with hole for thermometer 1 Package of Alka Seltzer tablets 2 digital thermometers Masking tape 1 incandescent light bulb on base for heat source Procedure: Place bottles (half filled with water) as close as possible to the heat source and at exactly the same distance. (see figure 1) Place small piece of masking tape over the hole on top of the stoppers in the bottles. Open Alka Seltzer and place in one of the bottles. (Make sure you remember which one.) Replace the stopper. (As the CO 2 enters the air in the bottle, enough pressure may build up to the point that the stopper pops out of the bottle. This should not be a problem, just put the stopper back on and continue.) Double check to see that the bottles are equidistant to the heat source. Put thermometers through the masking tape and into the hole in the stopper. Record the initial temperature of each bottle Turn on the heat source. Check and record the temperature of the bottles every 5 minutes until 30 minutes has passed. Plot data for both bottles on the graph. Use a different color pencil for each bottle Question 1) How did the temperature vary in each of the bottles? Question 2) Were you surprised by the results?

2 Greenhouse Gas Lab Temperature (⁰F) Time (minutes)

3 Part 2 Albedo Albedo describes the reflectivity of a surface; the greater the value for a surface s albedo, the more reflective the surface. For example, snow has a higher albedo than bare rock or soil. See figure 2 for a detailed description of the albedo for common surfaces. Question 3) Take this concept a step further and explain what you think might happen to the arctic ocean as ice cover decreases in the summer. Consider the albedo values given on figure 2. Procedure: Set a lamp on the table and set the black can on one side of the bulb and the shiny can on the other side. The cans should be raised off the table so that the center of the light bulb approximately corresponds to the center of the cans. Adjust the distance of the cans from the light bulb so that the center of each can is exactly 10 cm from the center of the light bulb. Push the thermometers through the covers so that the thermometer bulb will come to about the center of each can. Wait a few minutes until the temperature in each can reaches a constant value. Record this value. Turn on the lamp and read the temperature every 5 minutes for 30 minutes. After 20 minutes, turn off the light and remove the lamp and its base from the immediate vicinity of your cans. Continue reading the temperature every minute for another 10 minutes. Record the data on the graph below.

4 Plot data for both can the graph. Use a different color pencil for each. Albedo Temperature (⁰F) Time (minutes)

5 Question 4: How did your sample cans compare? Question 5: Were you surprised by your results? Question 6) Examine the Figure 4 and explain in your own words what the picture means. Question 7) What has this lab taught you about climate change and positive feedback mechanisms? (A positive feedback mechanism is a mechanism that enhances the process that causes the mechanism in the first place.)