Greenhouse In a Beaker Demonstration

Activity 5: Greenhouse in a Beaker Demonstration

&Background

This demonstration activity models the conditions that occur in a greenhouse, or in our atmosphere according to the greenhouse effect. Students will record data as your demonstration progresses.

Objective

ƒStudents will be able to explain that the greenhouse effect keeps the Earth warm. ƒStudents will be able to identify the parts of a model and relate them to real life. ƒStudents will be able to describe that too much carbon dioxide speeds up the greenhouse effect. Time

ƒ1 class period

 Materials

ƒ2 600 mL Beakers ƒ1 250 mL Erlenmeyer flask ƒ1 Rubber stopper with hole ƒ1 Vinyl tubing, 3/16” diameter ƒ1 Clip light ƒ1 Ruler ƒ2 Digital thermometers ƒ1 Small piece of masking tape ƒ4 Alka-Seltzer® tablets ƒSafety glasses ƒWater (room temperature) ƒ1000-1100 Lumen bulb, equivalent to 75 watt incandescent ƒDocument camera or similar (optional) ƒGreenhouse in a Beaker Data Worksheets, pg. 80-81

2Preparation

ƒMake copies of the data worksheets for students. ƒGather materials for the activity and be sure an outlet is available for the lamp. ƒCut the tubing length as appropriate for your set-up and materials. Usually, 1 ft to 18” lengths will be adequate, but it can vary based on the type of tubing used. ƒSet up a camera, if available, to project the demonstration for all in the classroom to see.

Procedure

INTRODUCTION

1. Review the student informational text sections on weather, climate, the greenhouse effect, and global climate change. 2. Explain that you are going to do a demonstration that will model or help to show how the greenhouse effect works. If necessary, remind students that models are ways to visualize something that might be hard to see. Models aren’t perfect examples of what is happening.

Sometimes models do things on a smaller scale, or with some different materials, and can’t always show things exactly as they are happening. 3. Set up the materials and pass out the data worksheets to the class. Give students instructions to complete the data table as your demonstration progresses. Give them time to summarize their data and answer the questions under each table. 4. Explain that you will do the demonstration twice, once to show daytime with light, and once to show night time or with no light.

PART 1 - DAY

1. Set up the light source 15 cm in front of the two beakers. The beakers should be receiving equal light. 2. Insert the tubing through the hole in the 250 mL flask, making sure to keep the tubing from reaching the bottom of the flask. Place the other end of the tubing near the bottom of one of the beakers. Secure the tubing inside this beaker with a small piece of masking tape. 3. Add 120 mL of water to the flask. Be sure the tubing is not in the water. 4. Turn on the clip light. Wait for the temperature in each beaker to stabilize. The temperatures in the beakers should be similar, but they do not have to be exactly the same. 5. Have a student read the temperature of each beaker. Instruct students to record this in the data table. 6. Break two Alka-Seltzer® tablets in half and drop the pieces into the flask. Secure the rubber stopper into the flask and make sure the tubing still leads from the flask to the beaker. 7. Have students record the temperature of each beaker every 30 seconds for three minutes.

PART 2 - NIGHT

1. Empty out the beakers and flask. Refill the flask with 120 mL water. Resecure the tubing inside one of the beakers. 2. Turn on the clip light. Wait for the temperature to stabilize. The temperatures in the beakers should be similar, but they do not have to be exactly the same. 3. Have a student read the temperature of each beaker. Have students record the temperatures in the data table. 4. Break two more Alka-Seltzer® tablets in half and drop the pieces into the flask. Secure the rubber stopper as done before. 5. Turn off the light. 6. Record the temperature of each beaker every 30 seconds for three minutes.

CONCLUSION

1. Explain to the students that the two beakers each show a model of our atmosphere. The beaker with no tube in it has a “normal” mix of air. The beaker with the tube has extra carbon dioxide from the bubbles of the Alka-Seltzer®. 2. Review student answers to the questions under each data table. Correct any misconceptions. Help students to complete the conclusion questions. 3. Ask the class why they think you did the “night” time version of the demonstration. Explain to the class that this shows us that if we didn’t have as much light from the sun, our atmosphere would not have any extra heat to trap in. 4. Connect this to planets, if appropriate. For example, some planets have similar atmospheres, but receive far less light, and thus are not warm enough to sustain life. Some planets receive plenty of light but have a different atmosphere and still aren’t warm enough to sustain life. Remind students that the greenhouse effect is a helpful feature of our atmosphere. However, if we add extra gases into the mix, like carbon dioxide, we can increase the effect in a bad way.

Greenhouse in a Beaker Data Worksheet

 ? Question

How does adding carbon dioxide to the air affect the temperature?

 Data

PART 1 - DAY

RANGE

Beginning Temperature 30 seconds 1 minute 1 minute, 30 seconds 2 minutes 2 minutes, 30 seconds 3 minutes

1. The temperature in the beaker without Carbon Dioxide went ___________. 2. The temperature in the beaker with carbon dioxide went ____________. 3. What was different about the two beakers?

BEAKER 1 (WITHOUT CO2) BEAKER 2 (WITH CO2)

PART 2- NIGHT

RANGE

Beginning Temperature 30 seconds 1 minute 1 minute, 30 seconds 2 minutes 2 minutes, 30 seconds 3 minutes

1. The temperature in the beakers _______________________.

BEAKER 1 (WITHOUT CO2) BEAKER 2 (WITH CO2)

1. The lamp is just like the _________________.

2. The greenhouse effect causes the temperature to go ______________.

3. Too much carbon dioxide causes the temperature to ___________________________________________.

4. Draw a picture of your teacher’s model.