Experiment: Stratification of water masses

If we drop an object into a liquid, two things can happen: it can float or it can sink. An experiment of about half an hour with water, a pinch of salt and food coloring to begin to learn about the sea, starting from the concept of density.

Instructions for use:

Use the document online or in paper format, as a recreational activity at home, or during a lesson at school.

Materials needed:

Tap water, 2 transparent rectangular containers, boiling water, fine kitchen salt, food coloring, 4 1-liter glass bottles, a notepad.

Procedure:

1. Prepare 4 different types of water, which you could easily collect in glass bottles:Type A: 1 liter of tap water with 80 grams of fine salt.

2. Type B: 1 liter of tap water.

3. Type C: 1 liter of very cold water: just leave it in the refrigerator for a couple of hours.

4. Type D: 1 liter of very hot water: heat the water until it is almost boiling.

5. Add a few drops of food coloring to distinguish the different types of water.

6. Pour the type A water into the rectangular container, and immediately after when the water is practically still, the type B water. Write down what you observe.

7. Pour the type C water into the other container, and immediately after when the water is practically still, the type D water. Write down what you observe.

8. Try to give an explanation for this particular stratification of the water masses.

Download the explanation 

Cognitive learning objectives:

• The student understands the basic concepts of different densities of ocean water.

• The student understands the relationship between temperature and salinity for the formation of water masses in the ocean.

• The student knows the physical and chemical properties of ocean water.

Social-emotional learning goals:

• The student is able to advocate for sustainable ocean management.

• The student is able to understand different perspectives on the impact of daily life on the ocean.

• The student is able to perceive the human connection between climate change and human health

Behavioral learning objectives:

• The student is able to express his/her personal relationship with the sea.

• The student is able to talk about the ocean and climate change with knowledge.

• The student is able to understand the importance of protecting the ocean.

• The student is able to make informed decisions regarding the ocean.

• The student is able to talk about the ocean correctly, in a coherent and informed way.

• The student is able to investigate the relationship of dependence of life on the sea.

• The student is able to understand the importance of protecting the ocean.

UNESCO Education for Sustainable Development Approaches:

Geographical perspective, scientific perspective.

Connection between subjects:

Marine ecology, natural sciences, physics, chemistry, computer science, technology.

Sustainable Development Goals:

• SDG 14 “Life Below Water”

• SDG 4 “Quality Education”

Connection to Ocean Education Principles:

• Principle 1 “The Earth has a large ocean with many features”

• Principle 2 “The ocean and life in the ocean shape the features of the Earth”

• Principle 3 “The ocean has a major influence on climate and weather”