Experiment and learn: What is the greenhouse effect?

It is very likely that your students have asked you this week: What is climate change, what is COP, and of course, what is the greenhouse effect? they hear terms they don't understand every day. So we want to help you explain it to them through a practical demonstration that will help them understand what the greenhouse effect is.

What are we going to do?

We are going to build a homemade thermometer and then design an experiment to test the increase in temperature produced by a closed jar exposed to the sun, like a greenhouse. They should relate the result of the experiment to the phenomenon that is happening on Earth and reflect on it.

Let's start… State the questions the experiment is intended to answer:

• What do you know about the "greenhouse effect"?
• Why does it occur?
• How does this experiment relate to what is happening on Earth due to gas emissions?
• What consequences is it having on our planet?

Students should design the experiment with this list of materials (this work is done in pairs):

• Two plastic bottles (with lids)
• Two straws
• One bottle of alcohol
• One bottle of liquid colouring
• One stick of playdough
• Two large clear plastic jars

Let's build the thermometer!

1. Pour the alcohol into one of the bottles to about a third of its capacity.
2. Add a few drops of coloring.
3. Make a hole in the lid and insert a straw, so that it doesn't touch the bottom but just touches it slightly.
4. Now put some plasticine on the lid around the straw so that no air can get in.
5. Finally, make a mark with a felt-tip pen on the liquid level in the straw. This way you will know how far the liquid reaches at room temperature.

How does the greenhouse effect affect temperature?

Now put your homemade thermometer in a large transparent jar with a lid and place it in the sun (or, if there is no natural light, under a lamp), to observe the increase in temperature concerning the ambient temperature. You can leave another homemade thermometer next to it to monitor the process.

They have to compare the experience they have had with what is told in this video and answer the questions posed at the beginning of this activity.