Idea for Use in the Classroom

After watching the video, have students brainstorm a list of reasons why an underwater robot might be useful for studying coral reef ecosystems and the capabilities it must have in order to explore a large reef. Then have students design an underwater robot that can change its buoyancy in order to map an ecosystem, such as a coral reef. In small groups, have students discuss what they know about the density of water at different depths and whether an object would sink or float based on what they know about the density of the water it is in.

Introduce models by explaining how scientists often draw diagrams or illustrations with detailed labels and explanations as a method for representing a process, concept, or system. Models include both the things they observe (what can be seen, felt, heard) and the unobservable features that explain how/why we observe what we do (for example, how an object might sink or float).

Challenge students to design a model for an underwater robot that can change buoyancy to reach different depths. Provide students with a before, during, and after model a template for them to draw the robot before it is lowered into the water, as it is lowered, and after it has been lowered into the water. Have students label and annotate the model and provide a detailed explanation below the model describing how the robot will change its buoyancy as it moves. 

Facilitate a gallery walk allowing students to compare and contrast their models with those of other groups by analyzing other group’s models and asking each other questions about how their robots are going to be able to change buoyancy in water.



the power to float or rise in a fluid.


number of things of one kind in a given area.


community and interactions of living and nonliving things in an area.


to rest on the surface of a liquid.


representation of a process, concept, or system, often created with a computer program.