Density in a Graduated Cylinder (Lilach Cary)

Author

Lilach Cary

Principle(s) Illustrated

• Substances that are more dense will sink, while substances that are less dense will float. In this lab students layer several different liquids after calculating their densities. Liquids with greater densities layer towards the bottom of the graduated cylinder.

• Once students have calculated the densities of the liquids tested and layered them, they then drop different solid objects inside. Students tend to believe that objects will either sink or float, but are not prepared for objects to sink in one substance, but float on another, leaving several objects suspended within layers of the graduated cylinder. These objects sink and float based on their densities, just like the liquids, and where they will end up can be calculated in a similar fashion.

Standards

• 5-PS1-3: Matter and Its Interactions

  • Make observations and measurements to identify materials based on their properties.

• PS1.A: Structure and Properties of Matter

  • Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.

• ETS1.B: Developing Possible Solutions

  • A solution needs to be tested, and then modified on the basis of the test results, in order to improve it.

Questioning Script

Prior knowledge & experience:

A substances density determines whether it will sink/float/remain suspended.

d=m/V

Root question:

What will happen to different liquids when they are poured into a graduated cylinder?

What will happen to solid objects when they are dropped into the graduated cylinder full of the different liquids?

Target response:

They will float in layers depending on their densities.

Common Misconceptions:

Students tend to believe that objects will either sink or float, but don't consider that whether they sink or float depends on the density of the fluid they are in. An object can sink in one layer of a fluid, but float in another.

Photographs and Movies

(photo from sciencewonderhowto.com)

References

WonderHowTo

YouTube Video of this Lab