Greenhouse gases: Oceans and our climate

Do it yourself

When we hear the terms "climate" and "climate change," we first think of how our planet is getting warmer and that it used to snow a lot more in the past. But there is much more to our climate. Few think about what changes in climate do to our oceans even though almost 70% of the Earth's surface is covered with water. In this experiment, you will become marine scientists and amateur chemists to find out more about what climate change is doing to seawater.

What is the connection between climate, gases and the sea? For this you must know that in water you can dissolve not only salt for making pasta, but also gases. These gases are found in the air we breathe and can affect and be affected by our climate. But what does a bottle have to do with all this? What effect does the temperature of the water have on its ability to absorb gases and is there such a thing as too much (as in salt water)?

Here we go - have fun!


You want to learn more about our oceans and greenhouse gases?

Why are our oceans so important? What exactly are greenhouse gases? And more importantly, what are they doing to Earth?
Below you will find additional information and links to information material that we have found online on the topic!


Overview

  • Suitable for age group: 10 years and older

  • Especially interesting for: Children and teenagers, amateur chemists and geologists

  • Preparation time: approx. 1h, including latency


Material

  • You need:

  • Bowl (medium sized)

  • Small funnel

  • Plastic bottle (0.5 l)

  • Tap water (warm and cold)

  • Fizzy tablets (e.g. vitamin C, magnesium…)

  • Felt pen/ Marker

  • Food colouring

  • Hydrophobic support


Preparation

Step 1: Dye warm tap water and fill up vessels

First, dye the warm tapwater  with food colouring (so that it looks nicer), fill the bowl about halfway and the bottle completely. Then put the funnel into the bottle and carefully put everything into the bowl with the opening facing down.



Tip

Make sure the funnel is not too small. Ohterwise the bottle will end up falling over.


Step 2: Put the fizyy tablet under the funnel

The fizzy tablet starts to bubble and carbon dioxide bubbles rise into the bottle. When the entire tablet has dissolved (after approx. 10-15 min), mark the edge of the gas bubble with a felt-tip pen.


Step 3: Repeat step 1 and 2 but with cold water

Compare the markings, what do you notice?






Solution of the riddle

If you have done everything correctly, the mark should be further up than with the warm water before. This is because the ability of the water to absorb gases depends on the temperature.


Step 4: Put a second fizzy tablet under the funnel

Lastly, another mini-experiment: If you add another fizzy tablet, you can draw another conclusion.

Now compare the markings again.






What do you notice and why?

The gas bubble has become larger with the 2nd tablet than with the 1st, this is due to the so-called saturation effect. You have probably already observed this with salt, at some point it no longer dissolves in the water.


Good luck with your little
sea experiment!


Learn more!

Most of us have heard of greenhouse gases. But what are they actually and why is are they important for us? Greenhouse gases include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gases absorb the long-wave (infrared) portion of the Earth's thermal radiation. Perhaps you already knew this, but our earth consistently emits heat, which it receives from the sun. Normally, this radiation is reflected and released back into the atmosphere.
So the shortwave radiation simply "passes through" the greenhouse gases, while the longwave radiation is absorbed and emitted. This means the atmosphere is less permeable to infrared radiation when more greenhouse gases are present. As if under a glass dome, the air now heats up. This makes the whole world warmer.

But that doesn't necessarily mean it's just a little bit warmer, it has some other effects. Among other things, the temperature of the oceans rises, which disturbs and upsets their inhabitants and entire ecosystems. Another problem you have demonstrated in the experiment.
The greenhouse gas carbon dioxide can be dissolved in water, but the colder the water, the more gases can be dissolved in it (in cold water there was less gas in your bottle than in warm water). That's why larger amounts of carbon dioxide from the air used to be able to dissolve in water. Another problem is supersaturation (due to dissolved carbon dioxide), which also leads to more carbon dioxide being released into the atmosphere (the 2nd fizzy tablet in the cold water resulted in more gas in the bottle than the 1st one).







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