Cartesian Diver

e. Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).

3. Structure of Matter – Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. All forms of matter are composed of one or more of the elements. As a basis for understanding this concept.

d. Students know the states of matter (solid, liquid, gas) depend on molecular motion.

e. Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.

8. Density and Buoyancy – All objects experience a buoyant force when immersed in a fluid. As a basis for understanding this concept:

a. Students know density is mass per unit volume.

b. Students know how to calculate the density of substances (regular and irregular solids and liquids) from measurements of mass and volume.

c. Students know the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced.

d. Students know how to predict whether an object will float or sink.

9. Investigation and Experimentation – Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:

f. Apply simple mathematic relationships to determine a missing quantity in a mathematic expression, given the two remaining terms (including speed = distance/time, density = mass/volume, force = pressure × area, volume = area × height).

Engineering Connection

Students will learn about the differences between compressible and incompressible fluids, an important concept in fluid mechanics for mechanical, chemical, civil, and environmental engineers. Also students will learn a little about density, buoyancy, and get hands on experience making a device – all things which engineers must know about in order to design boats, submarines, etc.

Prior knowledge & experience:

Root question:

How does a fish swim up and down through the water column? How does a submarine dive or surface? What causes a fish to do this?

Common Misconceptions:

• Adding more air will make an object float
• Adding more water makes the diver sink.
• Air is leaving the diver to make it rise

Photographs and Movies

Goldfish with swim bladder problems

Overfeeding Goldfish

d. Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction.