IGCSE Marine section 2.3 Dissolved gasses- an experiment

In this experiment we will look at section 2.3 in the syllabus

This shows how increasing the temperature of water decreases the amount of dissolved gasses in the water

So, what happens?

when the temperature of water increases, the particles move more

Dissolved gasses near the surface start to escape, by diffusing out of the water

Cold water will limit this

So, hot water will hold less dissolved gasses than cold water

this is also why your cold coke or beer tastes less "flat" than an warm one

Dissolved gasses in the ocean:

The solubility of Oxygen in sea water is very low. But there is a lot of oxygen in the air. This means that oxygen will diffuse into seawater and dissolve. This also means that we will have different oxygen levels depending on the depth

Carbon dioxide is more soluble in water than oxygen

The syllabus for this part states:

Candidates should be able to: 

1 explain that the gases oxygen and carbon dioxide from the atmosphere dissolve in water, and that oxygen has a low solubility in water 

2 compare the relative concentrations of oxygen and carbon dioxide in the atmosphere and dissolved in sea water 

3 describe and explain how an increase in temperature reduces the solubility of oxygen and carbon dioxide in water 

4 investigate the effect of temperature on gas (PA) solubility