The greenhouse effect experiment
Supplies
- 5 Jars – Using all 5 jars provides an opportunity to apply scientific theory and the scientific method.
- Vinegar – White, standard vinegar is best.
- Baking Soda – Also known as sodium bicarbonate or bicarb. Don’t use Baking Powder! It is a completely different chemical formula.
- Measuring cups and spoons
- Plastic Wrap – It must be clear and able to seal tightly without tearing. Unfortunately, plastic is needed for this science experiment. You can save the plastic and reuse it!
- Elastic bands – Large enough to fit over the mouth of the jar to secure the plastic wrap.
- Heat Source – A sunny window sill, a heat lamp, a space heater, or a heat vent/radiator. It just needs to provide lots of heat evenly between the jars.
- Thermometer – A non-contact infrared thermometer or standard dual scale thermometers. If you use standard thermometers you will need one for each jar and a small knife or sharp scissors.
- Masking Tape and Sharpie – For labeling the jars
Directions
Prepare the Jars
Start by labeling the jars. You will want:
- Air (control)
- Vinegar (control)
- Baking Soda (control)
- Reaction
The fifth jar does not need to be labeled, that one you will also be doing the reaction in, but without the plastic covering.
The reason we are doing all of these controls, is that we want to show that it is not just the vinegar or just the baking soda, or just the chemical reaction causing our result. We want to prove it is the trapped carbon dioxide gas.
Prepare a piece of plastic wrap big enough to cover the mouth of the jar with a bit of extra down the sides so it can be sealed completely. Repeat for 4 jars.
Add an elastic band for each piece of plastic wrap.
Place plastic wrap on the air jar and secure it with an elastic.
Add 1/4 cup of vinegar to the vinegar jar, then cover with plastic wrap and secure with an elastic.
Add 1 tablespoon of baking soda to the baking soda jar, cover with plastic wrap and secure with elastic.
Reaction Time!
his next step is easiest with two people.
Have one person read with the plastic wrap and elastic. The other person will add the baking soda to the jar, then add the vinegar.
VERY QUICKLY place the plastic wrap over the mouth of the jar and secure it with an elastic. We need to capture the gases from the reaction, so work fast!
Here comes the sun
Now place the jars in front of your heat source. Ensure they are positioned so they will all be heated evenly.
Leave the jars with the heat for 5 to 10 minutes. We tested at both the 5 minute and 10 minute mark.
This heat source is replicating the warming effect of the sun.
Chemical Reaction Comparison
While the four jars are warming, take your fifth jar. Add 1 tablespoon of baking soda and 1/4 cup of vinegar. Watch the bubbly reaction!
After about 30 seconds take a temperature reading. What do you notice? Baking soda and vinegar is an endothermic reaction! This is extremely interesting in the context of this greater experiment.
Temperature check
After your jars are warmed, it is time to take temperature readings.
If you are using a non-contact infrared thermometer, have your students take temperature readings from each jar, we found it best to aim straight down into the jar.
If you are using a standard thermometer, make a small slit in the plastic top of each jar, just big enough to slip the thermometer in without letting too much air escape. Place a thermometer in each jar. Wait one minute, then remove the thermometer and check the temperature readings.
What do you notice about the temperature readings? Record your results!
Greenhouse Effect Results
The chemical reaction in the enclosed jar is warmer than all the other jars with plastic covering. Those control jars are all about the same temperature. The coldest jar is the chemical reaction with no plastic covering. So cool!
The Greenhouse Science
The chemical reaction between baking soda and vinegar is an acid-base reaction. Baking soda is a base and vinegar is an acid. When we combine them, they react in a bubbly, endothermic reaction. Endothermic means it becomes colder during the reaction.
Here is the chemical formula of this reaction
C2H4O2 + NaHCO3 -> NaC2H3O2 + H2O + CO2(g)
vinegar + sodium bicarbonate -> sodium acetate + water + carbon dioxide(g)
Carbon dioxide is a gas, just like it is in the atmosphere, where it is one of the greenhouse gases.
In this experiment we are trapping the carbon dioxide gas in the jar. When heat is applied, the carbon dioxide traps more heat in the jar than our controls.
Where this becomes really interesting, is when the students realise the reaction is endothermic, as demonstrated in our open chemical reaction jar. That means the jar with the trapped carbon dioxide not only traps heat, but it traps enough heat to counteract the endothermic reaction, and still make that jar warmer than the controls.
That is one powerhouse of a greenhouse effect!
Troubleshooting
If you have problems with this experiment there may be a few things to look at.
First, make sure your jars are being evenly heated. Depending on how you heat your jars, certain jars may be getting more heat than others. If you are using heat lamps, you may want to ensure you have one heat lamp per jar and place them equal distances from each jar.
If you use a standard thermometer, make sure your slit is not letting too much of the carbon dioxide out of the jar, it will take the heat with it.
When the reaction is triggered, make sure you act fast to get that plastic wrap on there and trap those gases!
Source: https://www.steampoweredfamily.com/activities/the-greenhouse-effect-experiment/