Activity 5: Density

Activity: Density   110_Activity_Density.docx

The first part of the lab is a computer simulation. The second part is a hands-on lab activity. (Scroll down to see the ingredients needed.)  Both deal with a property of chemicals called density.  You will complete the assignment by doing the quiz, using the simulation and hands-on activity as described below and in the quiz.

Videos to help with this concept:  (a) Eureka! Volume and Density: https://www.youtube.com/watch?v=GMNpPgLT8Fk  (4:50)

(b) Density calculation and concept by Mark Drollinger
https://www.youtube.com/watch?v=SimFy9wOMXY (3:13)

Background and Purpose
Density is a property of materials. It is the ratio of how heavy a substance is (its mass) and the amount of space the substance takes up (its volume).  

The purpose of this homework is to:

• learn how to measure volumes by displacement of liquids, 
• provide evidence and reasoning for how objects of similar mass can have different volumes, and how objects of similar volumes can have different masses (and how each of those cases relates to density), and
• identify unknown materials by calculating density values and comparing them to known densities of substances.

This assignment is constructed as a Canvas quiz. The following resources will be needed to answer the questions.

For Part 1 you will need the density simulation. Find the simulation online:

Or go to the University of Colorado – Boulder PhET website at:  http://phet.colorado.edu 
Click “Play with Sims”, then click “Chemistry” on the left-hand side menu.  Find the “Density” Simulation and click RUN (or you can download it if you prefer).This simulation requires Java – if you don’t have it, install it for free at http://java.com/en. If you have difficulty, contact your instructor asap.

Settings to use:

Notice that you have many settings to play with. You can choose a material (wood, aluminum, ice, etc.) or you can make your own (custom) block of set dimensions and properties (mass, volume, density).

This part will be graded by Canvas.

 

Part 2 is a hands-on activity. You will need the following materials:

two alka seltzer tablets
vegetable oil (or any other kind of oil which floats on water)
optional: food coloring 

This part is also in the Canvas quiz but will be manually graded by your instructor. Do not be alarmed if the points do not get added to your score immediately!

 

Fun applications:

(a) rainbow density column:
https://www.youtube.com/watch?v=-CDkJuo_LYs  (1:25)

(b) How to layer cocktails: https://www.youtube.com/watch?v=OPbq8SgAAb0 (1:41)