Are you looking for an easy way to explain the greenhouse effect to kids? We have not one but three hands-on experiments that will make the greenhouse effect easy to understand and will clear up some common misconceptions.
My kids first got interested in the greenhouse effect after reading Polar Bear, Why Is Your World Melting by Robert Wells. They got very worked up by the questions raised in the book.
“We have to do something!” exclaimed my almost 10-year old while pacing the living room.
“Animals need our help!” said my 7-year old, who sleeps with animal encyclopedias under her pillow.
“I hate the greenhouse effect! It’s evil!” said my 5-year old with tears in his eyes.
Do you think that the greenhouse effect is bad, too? Do we want to get rid of all greenhouse gases? After spending the last few days asking random children and their parents their thoughts on The Greenhouse Effect, we discovered that many are confused about what it is and how it works. Read on to brush up on the facts.
Question 1: What is the Greenhouse effect?
Without the greenhouse effect, life on Earth as we know it would not be possible. The greenhouse effect is a very natural and essential process. It has been around for millions of years.
During the day, the sun shines on planet Earth. But only about one half of the sun’s energy actually reaches the Earth (26% of the solar energy (energy from the sun) is lost in space, and 19% is absorbed by atmosphere/cloud).
At night, most of the sun’s energy escapes back into space. Most but not all. Thanks to the greenhouse effect, some of the heat is trapped in the atmosphere, and it protects us from the chill of space. The greenhouse effect is what keeps the Earth’s temperature stable.
Let’s see how it works with this easy outdoor experiment.
Experiment 1: The Tale of Two Thermometers
In this outdoor experiment, we are going to test what happens to the temperature in a covered glass container on a sunny day. Ask kids to hypothesize what will happen and why.
What you need:
- Two thermometers
- A clear bowl, jar, or vase and something to cover it
- Recording Sheet (print ours)
What to do:
- Lay both thermometers for a few minutes outside in a sunny area.
- Mark down the time and the temperatures of both thermometers on your record sheet (link ours).
- Place a vase in the sun with a thermometer in it. Cover it with a plastic wrap or a dark t-shirt.
- Place the second thermometer next to the bowl (not in the shade).
- Record the temperatures on both thermometers every 5-10 minutes.
Why are the temperatures inside and outside of the vase different?
Kids can record their observations with our printable or just ask them to sketch by hand in a notebook. You can get all of our Printables in our subscribers-only library of resources. Click here to subscribe.
What it means:
Solar energy (light) goes inside the vase and is changed into thermal energy (heat). This heat cannot escape the vase. It’s trapped, and the air inside of the vase gets warmer and warmer as more light (solar energy) enters the vase. This is very similar to the greenhouse effect (we will talk more about gases in the next experiment).
The second thermometer is exposed to air. Even though it doesn’t seem like much is happening in the air, a lot of factors are at work that allow the warmer air to mix with the cooler air in a constant interactive dance.
Question 2: What are the greenhouse gases?
The greenhouse effect means that some of the sun’s energy is trapped in the Earth’s atmosphere. But what traps it? Gases! Let’s talk about these gases now.
Greenhouse gases trap energy from the sun. They absorb the heat and prevent it from going back into space.
There are many different gases. Some you might have heard of are water vapor, carbon dioxide, ozone, nitrous oxide, and methane.
Let’s look at carbon dioxide in action.
Experiment #2: Sandwich Bag Explosion
The reaction between baking soda and vinegar produces carbon dioxide gas. In this second outdoor experiment, we will test what happens when there is more carbon dioxide than the bag can hold. Ask kids to hypothesize what will happen to bags once the substances mix and why.
What you need:
- 4 plastic sandwich bags (and maybe more for backup)
- baking soda
- toilet paper roll to make 4 toilet paper pockets to hold soda
What to do:
- Lay out toilet paper squares and place 2 tablespoons of baking soda in the center of each one. Fold your soda pockets carefully. We used 3 squares for each pocket.
- Fill plastic bag #1 with 2 tablespoons of vinegar, bag #2 with 8 tablespoons, bag #3 with 12 tablespoons, and bag #4 with a 50/50 mixture of vinegar and water (say 5 tablespoons of vinegar and 5 tablespoons of water).
- Drop a soda pocket into each plastic bag in turn and seal quickly. (Don’t worry! It’s not going to explode in your eyes. The tissue buys enough time to seal the bag)
What happens when we add baking soda to the vinegar? Why did the bags pop? What amount of vinegar created the best reaction?
Record your observations.
In this experiment, two chemicals work together to create carbon dioxide gas. Once the baking soda and vinegar mix, carbon dioxide gas starts to fill the bag until it runs out of room and POP goes the bag.
You can try this experiment with more and less baking soda and vinegar to test what amounts produce the best reaction.
Questions 3: So why do we keep hearing that the Greenhouse effect is bad?
If the greenhouse effect is something we need to sustain life on earth and it has been around for millions of years, why do we keep hearing about how bad it is?
Ever since the industrial revolution, and especially in the last few decades, human activities increased the amount of greenhouse gases in the atmosphere. It means that more heat is trapped in the atmosphere than ever before, which upsets the Earth’s energy balance.
It means that the Earth’s natural systems, such as weather patterns, water level balance, and ecosystems, change negatively. You have probably heard about the population of polar bears decreasing as the Arctic ice continues to melt, but do you know that bacteria and viruses trapped in ice for thousands of years are now being released as the ice melts?
Experiment #3: How heat can harm plants and melt ice
We need the energy from the sun to survive, but too much of a good thing can be bad. A car parked in the sun on a hot day is a great model of the greenhouse effect. In this experiment, we are going to wilt a plant and melt some chocolate in a parked car.
What you need:
- Two plants of the same size
- A car
- A sunny day
- 2 thermometers
- 2 chocolates, each inside its own plastic bag
- A record sheet (from experiment #1)
What to do:
- On a sunny day, place one chocolate (inside a plastic bag) and one of your plants inside a car. Roll up all the windows.
- Place one of the thermometers inside the car in such a way that you can see the readings.
- Close the car door.
- Place the second plant, chocolate (inside a plastic bag), and the second thermometer outside the car.
- Check back every 10-15 minutes and write down the readings on your observation sheet.
- Warning for adults: Keep an eye on the temperature reading! It can get pretty hot inside the car. Take the thermometer out before the mercury reaches the top to prevent it from bursting!
- After recording a few readings, you can take the thermometers inside the house and leave the plants and the chocolate inside the car for a few hours.
What happened to the plant and the chocolate?
Variation: You can try this experiment again with the windows cracked upon.
What does it mean:
The temperature inside a parked car on a sunny day can be 160 (80C) degrees higher than outside the car! Sunshine (solar energy) goes through the car windows and heats up the interior. Depending on how hot of a day it is, there might be enough heat trapped inside to bake cookies!
Books and Videos
Polar Bear, Why is Your World Melting by Robert E. Wells. This is not only our favorite book about the greenhouse effect, but one of our top non-fiction favorites of all times.
Earth In The Hot Seat by National Geographic is visually stunning and educational. We liked the quiz to calculate our personal carbon footprint and the tips on how to reduce it.
Why Are The Ice Caps Melting? We love all Anne Rockwell books and this one is no exception. I like the ink-and-watercolor art, actional steps (i.e., buying food that isn’t prepackaged. Bye-bye cookies!) and simple explanations.
The Lorax by Dr. Seuss. It’s a classic for a reason. The rhyming test and groovy drawings deliver the powerful message that unless we start caring, things can get pretty bad for Mother Earth.
The Magic School Bus and The Climate Challenge byJoanna Cole. This is a great series. I like the scientific facts, simple explanations and the message that the kids can help solve the problem.
Global Warming 101. This very short video from National Geographic got almost 3 million views for a reason.
The Greenhouse Effect. This video from US Environmental Protection Agency packs a lot of information in 2 minutes.
Are you looking for more Spring Science Ideas?
Related: Start a Seed Garden in One Day
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