Greenhouse Effect Lab 

The most abundant gases in the atmosphere—nitrogen, oxygen, and argon—neither absorb nor emit infrared radiation (heat). But clouds, water vapor, and some relatively rare greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the atmosphere can absorb and reemit radiation.  Greenhouse gases in the atmosphere therefore will radiate heat energy both to space and back towards Earth. This back-radiation (to Earth) warms the planet's surface.

 

The greenhouse effect is important. Without the greenhouse effect, the Earth would not be warm enough for humans to live. But if the greenhouse effect becomes stronger, it could make the Earth warmer than usual. Even a little extra warming may cause problems for humans, plants, and animals.

Objectives:

 

Part A:  Measuring Room Temperature & Heated Bottle

  1. Obtain materials:
  1. Soda bottle
  2. Cap with a hole drilled in it
  3. Thermometer probe
  4. Computer
  5. Lamp.

  1. Open Logger Pro application running on the computer; insert the Vernier Temperature Probe into the computer; you should see a graph with axes set up for temperature in degrees Celsius (Y) and time (X) once plugged in.
  1. If it’s not ready, go to “experiment” and “set up sensors” and “show all interfaces”.  Then, select the port or channel you plugged the temperature probe into (should be channel 1).  Select “choose sensor” and select “Temperature” from the list, then select “standard temperature”.  Now the graph should show up properly with temperature on the Y axis.

  1. Record room temperature by holding the temperature probe in the air for 1 minute and then recording the reading.  Record your reading in Table 1. NOTE: Do not just set the probe on a desk.  Then you will be recording the desk temperature.  Also, don’t hold the metal part, because then you’ll be taking your temperature.

  1. Plug in the lamp, turn it on so it warms up but shine it away from the bottle; don’t put the bottle near the light.  You want the bottle to be at room temperature when you start the experiment.

  1. Screw the bottle cap onto the bottle

  1. Place the thermometer probe into the hole in the cap.

  1. Set up Logger Pro to collect temperature data for 5 minutes
  1. Click on the “Clock Icon” in it (next to the green record button) and type in “300” to the time box (in seconds) for a five minute reading.
  2. Set the seconds/sample to 30; you will have a total of 11 readings.

  1. Turn the light on the light source and move it to exactly within 25 cm from the bottle; begin collecting data.

  1. After data collection, turn the light off and take the cap off the bottle to cool the bottle back to room temperature.

  1. Record collected data in Table 2.

  1. Clear the data after you’ve recorded what you need by clicking on “Experiment” and “Clear latest run.”

 

Table 1.  Room Temperature Reading

Room Temperature Reading (Celsius)

Table 2. Temperature of Heated Bottle per Seconds

Elapsed Time (seconds)

Temperature (Celsius)

0

30

60

90

120

150

180

210

240

270

300

Baking Soda and Vinegar Background: Vinegar and Baking Soda react when they come in contact with one another.  They cause a fizzing reaction that you may have observed before.  The fizzing and bubbling indicates that a gas is being produced as the solid baking soda and liquid vinegar react.  Chemically, here is the process:

 

Vinegar is acetic acid:  CH3COOH

Baking soda is sodium bicarbonate:  NaHCO3

Mixing the two is simply an acid / base reaction.

                                        CH3COOH  +  NaHCO3  --->  CH3COONa  +  H2CO3

That last product is carbonic acid which quickly decomposes (falls apart) into carbon dioxide and water:

                                        H2CO3  --->  H2O  +  CO2

The CO2 is what you see foaming and bubbling in this reaction.

 

CO2 gas is more dense than air.  It will stay in the beaker, forcing out the air.  You can pour CO2 gas out the beaker, just like you would pour a liquid.  You can feel the CO2 being poured out of the beaker because it’s cold.  The reaction with baking soda and vinegar is “endothermic” meaning it requires energy, leaving the products of the reaction, including CO2, cold.

 

Part B: Measuring Temperature with CO2 

  1. Obtain materials:
  1. All the supplies from Part A
  2. A beaker (500mL)
  3. 90 mL vinegar in a graduated cylinder
  4. 15 grams of baking powder in a weigh boat
  5. Plastic spoon

  1. Set Logger Pro to collect temperature data for 5 minutes
  1. Click on the “Clock Icon” in it (next to the green record button) and type in “300” to the time box (in seconds) for a five minute reading.
  2. Set the seconds/sample to 30; you will have a total of 11 readings

  1. Be sure the temperature probe and bottle are at room temperature again.

 

  1. Inside the BEAKER (not bottle), add 5 g of baking soda and 30 mL of vinegar.  Allow the reaction to bubble and fizz without disturbing it.
  1. Note: adding more vinegar and baking soda will just make the reaction bubble excessively.  The CO2 will bubble over the beaker and you won’t be able to get it into the bottle.

  1. When the fizzing is over, carefully pour the CO2 into the bottle.  BE SURE NOT TO POUR ANY LIQUID INTO THE BOTTLE!

  1. Repeat steps 4 and 5 two more times.  In the end, you should have poured CO2 three times.

  1. Turn the light on the light source and move it to exactly within 25 cm from the bottle; begin collecting data.

  1.  Quickly put the cap on the bottle and insert the temperature probe to the bottle and start collecting data.

  1. After 5 minutes, turn the light off and rinse out the bottle.

  1. Record collected data in Table 3.

Table 3. Temperature of Heated Bottle with CO2 per Seconds

Elapsed Time (seconds)

Temperature (Celsius)

0

30

60

90

120

150

180

210

240

270

300

Data Analysis:

  1. Submit collected data from all Tables to the following form found here.

  1. Create a graph that displays the change of temperature over 5 minutes for both the empty bottle and bottle with CO2 from the class averages found here; your graph should include error bars.

  1. Upload your graph here:

Evaluation:

  1. Which experiment resulted in the highest temperature change?  Use data to support your answer.

  1. Describe the general trend the temperatures took over time, including a comparison of the two tests and the significance of the data sets.

  1. What was happening to the light inside the bottle?

  1. What effect did adding CO2 have on the heat trapped in the bottle?  Use data to support your answer.

  1. Explain the greenhouse effect using examples from the lab to justify your explanation.  Include a comparison of your results to the accepted scientific context of the greenhouse effect.

Assessment:

Lab Standard: Evaluation

Exceeds

Meets

Nearly Meets

Beginning