• Assess students’ ability to observe and record data by monitoring the density lab.

• Provide feedback on misconceptions or incorrect responses for groups or individuals.

• Collect Density Lab Activity Sheet for individual feedback and comments.

• Review the extension activities for individual assessment.

In this lesson, students will learn that there is a difference between weight and mass. The concept of weightless was not fully understood until we explored space. Keep in mind that many are confused over the difference between weight and density. Many times, mass has been improperly referred to as the amount of stuff in something.

Begin the lesson with the explanation of density followed by a density activity.

Explain density to students using the following scenario:

“Have you ever been in a crowded movie theater, grocery store, swimming pool, or shopping mall? If you answered yes, you are familiar with the idea of density. Picture this school classroom with only five students in it. Now think of this same classroom with 30 students in it. The classroom is the same size in each case, but the number of people is different.”

Ask students, “Which classroom situation has a higher density?” Allow a few students to respond. Explain that if they said the class of 30 students, they are correct. More students in the same sized space mean a higher population density.

Display a copy of the density background information on an overhead or interactive white board (S-6-5-2_Density Notes.doc). Note: Each student should receive a copy to place in his/her science journal/lab/folder. Students will need this sheet to complete a future assignment.

Divide students into groups of four. Hand out a copy of the Density Lab Activity Sheet (S-6-5-2_Density Lab Activity Sheet and KEY.doc). Tell students to read the background information sheet and glue it in their science journals or lab notebooks or place in science folder. Remind students that they will need the background information sheet at the end of the lab. Allow students to begin the lab after you have observed that each group is prepared and ready to start.

Once students have completed the activity, have them report their observations and explanations on the lab worksheet. This can be completed in class or assigned for homework.

• Students should notice that the oil stays on top for lab question #1. This happens because oil is less dense than water, so it is able to float on top of it. If you were to add some other objects to this glass they would float or sink according to their densities.

• Students should explain that ice floated for lab question #2. The density of ice is very important to living things. During the winter, lakes form layers of ice on the surface, but there is still liquid water (which is more dense) below. This allows fish and other animals to survive during the winter.

• The sand sank to the bottom of the cup for lab question #2b, and the pencil shavings floated for lab question #2c.

Extension:

• Students who might need opportunities for additional learning can create a table of six materials, also listing whether they are more dense or less dense than water.

Answers will vary on materials chosen.

 

• 	MORE DENSE THAN LIQUID	LESS DENSE THAN LIQUID
  Granite	X
  Hydrogen gas		X
  Soil	X
  Styrofoam		X
  Aluminum	X
  Ice		X

  Students who are going beyond the standards can complete problem solving sets (S-6-5-2_Problem Solving Sets and KEY.doc).