oceanservice.noaa.gov 22

Activity 6: I Didn’t Do It...Did I?

What You Will Do: Make Your Own Greenhouse Effect (adapted from Lambert, Cottongim, and Leard, 2009)

More than 90% of climate scientists agree that Earth’s average global temperature has increased since 1950, 

and the cause of this increase is human activities. These 

scientists also agree that most of the temperature increase is 

due to burning fossil fuels, which has increased the levels of 

greenhouse gases like carbon dioxide in Earth’s atmosphere.

Two things happen when sunlight reaches Earth: 

1. The land, ocean, and atmosphere absorb some of the 

sunlight’s energy; and

2. They return some of this energy back into space. 

Earth’s atmosphere is a mixture of many gases. The most 

abundant are nitrogen (about 78% of the total atmosphere) and 

oxygen (about 21% of the total atmosphere). Other gases are 

present in much smaller quantities, yet are still very important 

for life on Earth, because they trap some heat in the atmosphere 

and prevent it from escaping to outer space. Heat-trapping 

gases are called greenhouse gases, and include water vapor, 

carbon dioxide, and methane. If the amount of greenhouse 

gases in the atmosphere increases, then more heat is trapped 

and Earth becomes warmer (for a short animation about how 

this works see http://epa.gov/climatechange/kids/basics/index.

html). 

Since the Industrial Revolution, widespread burning of fossil 

fuels has increased the concentration of greenhouse gases, 

mostly carbon dioxide, in Earth’s atmosphere, and Earth’s 

average temperature has increased. Other human activities have 

also changed Earth’s atmosphere, as well as its land and ocean. 

Climate change caused by human activities is making it difficult 

for some species to survive. Scientists predict that there may 

also be positive benefits from climate change, such as longer 

growing seasons in some areas and less ice to interfere with 

ships passing through the Arctic Ocean. Overall, though, climate 

change is expected to produce more problems than benefits.

How It Works

Heat-trapping gases in Earth’s atmosphere are called 

“greenhouse gases” because they reduce the amount of heat 

that is lost to outer space, but this is not actually the way a 

greenhouse works. It is hot inside a greenhouse because the 

glass allows objects inside to absorb heat from sunlight and 

prevents wind from carrying heat away. Greenhouse gases trap 

heat in the atmosphere, but do not form an actual barrier like 

glass in a greenhouse. Ozone is also a greenhouse gas, but holes 

in the ozone layer have nothing to do with global warming.

How to Do It

1. Read through all of these steps before you start!

2. Ask your adult partner to use the scratch awl to punch a hole 

in the caps of the drinking water bottles. The holes in two of 

the caps should be just large enough to fit the thermometers, 

and the hole in the third cap should be just large enough to fit 

the plastic tubing. Ask your partner to also punch a hole in the 

side of one of the drinking water bottles about 25 mm (1 in) 

from the top. Label this bottle “CO2” with the felt tip marker.

3. Put the thermometers and plastic tubing into the caps, and 

make a tight seal using modeling clay. The thermometers 

should extend about 40 mm (1.5 in) below their caps, and 

the tubing should extend about 25 mm (1 in) below its cap 

(Figure 1A).

What You Will Need

Adult Partner

1 – Scratch awl or icepick

3 – Clear plastic drinking water bottles, 

about 500 ml (1 pt) capacity

1 – Vinyl tubing, about 3 mm (1/8 in) 

inside diameter, about 60 cm (2 

ft) long (tubing for aquarium air 

systems works well)

2 – Thermometers (such as Forestry 

Suppliers #89323; these 

thermometers have an aluminum 

case which makes them useful for 

field investigations as well as in 

your laboratory)

Modeling clay (the kind that doesn’t 

harden, not the kind you bake)

White vinegar, about 250 ml (1 c)

Baking soda, about 40 g (2 tablespoons)

Funnel

Safety glasses

Felt tip marker

Heat lamp (if you don’t have a sunny 

location)

Big Idea

Human activities are impacting the 

climate system. 

(Climate Science Principle 6)

Discover Your Changing World with NOAA
23

6. I Didn’t Do It...Did I?

Climate Science Principle 6. Human activities are impacting the climate system.

4. Poke the free end of the plastic tubing into the 

hole in the side of the drinking water bottle so 

about 25 mm of the tubing is inside the bottle. 

Make a tight seal using modeling clay (Figure 1B).

5. Put one of the caps with a thermometer onto 

one of the bottles that does not have the plastic 

tubing attached. Screw the cap on snugly. Label 

this bottle “Air” with the felt tip marker.

6. Put the other cap with a thermometer onto the 

“CO2” bottle. Screw the cap on enough to keep 

it attached to the bottle, but loose enough so 

that air can escape if you squeeze the bottle 

(Figure 1C).

7. Use the funnel to 

place about 40 g 

(2 tablespoons) of 

baking soda in the 

unlabeled water 

bottle.

8. Get ready, because 

now you have to 

work fast. Pour 

about 60 ml (2 oz) 

of vinegar into the 

bottle with the 

baking soda, and 

QUICKLY fasten the 

cap with the tubing 

to the bottle. The 

easiest way to do this 

is to have one person 

pour the vinegar while the other person holds the 

bottle in one hand and the cap in the other hand. 

As soon as the vinegar is in the bottle, bring the 

cap and bottle together and twist the BOTTLE to 

make the seal. The mixture in the bottle will foam 

up vigorously, then gradually calm down. The 

bubbles are carbon dioxide gas, which will flow 

through the plastic tubing to the bottle with the 

hole in the side (Figure 2).

Gently swirl the bottle to move the vinegar 

around, and you should be able to stir up some 

more bubbles. When no more bubbles appear, 

remove the bottle from the cap, pour another 60 

ml (2 oz) of vinegar into the bottle, and quickly 

replace the cap. Repeat this process until you have 

Figure 1A.

CO2

CO2

AIR

CO2

Baking Soda

Carbon Dioxide

Bubbles

Vinegar

Figure 1C.

Figure 2. Figure 1B.
oceanservice.noaa.gov 24

Temperature (°C)

Time (min): 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Air

CO2

Table 1. Record Your Data

added about 250 ml (1 c) of vinegar to the 

bottle. You should notice that the baking soda 

is gradually disappearing.

9. Remove the plastic tubing from the side of 

the bottle with the hole, and quickly seal the 

hole with modeling clay. Tighten the cap on 

the bottle.

10. Place both bottles in the sun, or near 

a heat lamp. Immediately record the 

temperature of both thermometers in the left 

column (labeled “0”) of Table 1. Record the 

temperature every minute for 15 minutes. It 

doesn’t matter if the two thermometers have 

different readings at the beginning, because 

the important thing is how quickly and how 

much the temperature changes in each 

bottle.

11. When you have recorded data for 15 

minutes, construct a graph of these data. Your 

data should show that temperature increased 

in both bottles; but the temperature changed 

most quickly in the bottle with carbon dioxide, 

and the total temperature increase was greater in 

this bottle as well. Both bottles had a greenhouse 

effect, but adding carbon dioxide increased 

this effect; just as carbon dioxide added to the 

atmosphere by human activities has increased the 

greenhouse effect on Earth!

Note to Adult Partners

Lambert, Cottongim, and Leard (2009) describe an 

alternative method for this demonstration using 

dry ice to supply carbon dioxide. This may be 

somewhat quicker than the baking soda/vinegar 

method described here, but introduces additional 

hazards. If you want to use this method, be sure 

that your young partner understands the 

dangers of severe cold, and NEVER put 

dry ice and water into a sealed container. 

Closed plastic bottles containing dry ice 

and water can easily explode, creating 

dangerous shrapnel that can seriously 

injure anyone nearby.

Lambert, J., Cottongim, L, & Leard, C. (2009). 

Investigating the greenhouse effect Oceanography. 

Published activity. (http://www.oceanography.org/

hands-on/activities/lambert_hands-on.pdf) 

Dry Ice can be DANGEROUS!!!

Discover Your Changing World with NOAA

Graph 1. Graph Your Data

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Temperature (°C)

Time (minutes)
25

6. I Didn’t Do It...Did I?

More About Carbon Dioxide

Here are two famous graphs. Graph 2 shows 

measurements of carbon dioxide in the atmosphere 

at the Mauna Loa Observatory that began in 1957. 

This graph shows annual variations in carbon 

dioxide concentration caused by changing growth 

rates of plants during the seasons of the Northern 

Hemisphere, and also shows a steady increase in 

atmospheric carbon dioxide that has continued 

every year since the measurements began. Graph 3 

shows atmospheric carbon dioxide concentrations 

over the last 420,000 years based on studies of polar 

ice cores. During ice ages, carbon dioxide levels 

were around 200 ppm, and rose to about 280 ppm 

during the warmer periods between the ice ages. 

Since the Industrial Revolution, atmospheric carbon 

dioxide concentrations have risen to much higher 

levels. The evidence contained in these two graphs 

is why most climate scientists agree that human 

activities have increased the concentration of 

carbon dioxide in Earth’s atmosphere.

Is the greenhouse effect a bad thing? Definitely 

not, because life on Earth would not exist without 

it! But too much greenhouse effect can also cause 

problems. Venus has a thick atmosphere made 

of 96% carbon dioxide (compared to Earth’s 

atmosphere that contains less than 0.04% carbon 

dioxide). The greenhouse effect on Venus is much 

larger than on Earth, and Venus has a surface 

temperature of about 450°C! Mars, on the other 

hand has a very thin atmosphere, only 1/100th as 

dense as Earth’s. Most of Mars’ atmosphere is 

carbon dioxide (95%), but the greenhouse effect is 

insignificant because the atmosphere is so thin. As 

a result, the surface temperature of Mars is around 

-53°C. These facts are summarized by the “Goldilocks 

Principle”: Venus is too hot, Mars is too cold, and 

Earth is just right. 

Want To Do More?

Find out about Charles David Keeling, the science 

hero behind the atmospheric carbon dioxide 

measurements at Mauna Loa Observatory: http://

scrippsco2.ucsd.edu/index.php

Graph 2. Measurements of carbon dioxide in the atmosphere at the Mauna Loa 

Observatory since 1957.

http://www.esrl.noaa.gov/gmd/ccgg/trends/

Graph 3. Atmospheric carbon dioxide concentrations over the last 420,000 years.

http://scrippsco2.ucsd.edu/program_history/keeling_curve_lessons_4.html

Climate Science Principle 6. Human activities are impacting the climate system.