Density Comparison of Water and Ice
Subject Area: Chemistry
Grade Level: Middle School Chemistry
Lesson Title: Density Comparison of Water and Ice
National Science Standards:
 Science as Inquiry: 5-8
 Science as Inquiry: 9-12
Physical Science Standards:
 properties and changes of properties: 5-8
 structure of atoms: 9-12
 structure and properties of matter: 9-12
 chemical reactions: 9-12
Suggested Prior Knowledge: concepts and relationships of mass, volume, and temperature
Purpose: To give students an understanding of waters density as a liquid and solid
Key Vocabulary:
freezing point - the temperature at which a substance turns from a liquid into a solid;
water is different from nearly all other substances because it is densest in liquid form at
about 4 o C., less dense in solid form at 0 o
hydrogen bonds - weak bonds that form between small molecules, specifically involving an
atom that has a partial negative charge, especially oxygen in water and in living things, and
another atom (such as hydrogen) having a partial positive charge; results in 'sticking
together' of molecules
polarity - possessing two opposed poles; a characteristic of molecules which have unequal
distributions of charge; water is polar because the oxygen has a partial negative charge and
the hydrogen atoms each have a partial positive charge; polar molecules interact with
other polar and charged molecules and ions.
density - Density of a material is defined as its mass per unit volume.
Objectives:
1. Students will be able to describe the density of water as a liquid and a solid
2. Students will conduct an experiment that visually demonstrates the density of water and ice
3. Students will be able to calculate the density of water and ice
Materials: insulated gloves as needed, plastic 100ml graduated cylinder, freezer, distilled water,
hot plate, 200ml beaker, beaker tongs, pipette, safety goggles.
Procedure:
1. Discuss with students how we can design an experiment that allows us to examine the
density of water or ice. lead the students towards a technically correct experiment that would
yield accurate results. As the students develop the procedure, the teacher should validate and
prioritize their answers in order to create a valid procedure similar to the one in this lesson
plan. Begin with a leading question and follow-up:

What is the difference between water and ice?

What can water do that ice cannot?

What does density measure?

What kind of experiment can we do to find the density of water and ice?
2. Lab safety equipment and protocols should be followed. The following can be completed as a
teacher demonstration or as a class experiment:
3. Record the dry mass of the plastic graduated cylinder.
4. This experiment works best with water that is free of dissolved oxygen or minerals. By using
water that is distilled and free of oxygen your ice will be clear and easier to read its volume
when frozen.
For this, boil approximately 100ml of distilled water for 2-3 minutes in a 200ml beaker to
remove most of the oxygen from the solution.
5. Then, using your beaker tongs transfer the hot liquid to a plastic graduated cylinder to
exactly 50ml (note: a glass graduated cylinder may rupture). If necessary, use a pipette to
transfer hot water as required to ensure accuracy.
6. Place the cylinder with 50ml of hot water in a freezer until completely frozen solid (several
hours). Your ice will be clear.
7. Remove the beaker from the freezer and record the volume of ice.
8. Have the students record the data and calculations from this experiment.
9. Have students calculate the density of both ice and water. (D=M/V) (ice=0.92 g/ml, water
=1.0 g/ml)
10. Have students draw a conclusion about the properties of water vs. ice.
11. After the students have drawn conclusions regarding the volume and density of water in
liquid and solid form, finish the discussion as to why ice has a greater volume than water. The
molecular diagram of ice below can be used to show how the hydrogen bonds are equidistant
from their neighboring water molecule. The concept of polarity of water can be introduced to
explain why the volume of ice is greater than water in the experiment.
Image source: ibchem.com
Additional Resources:
http://www.lpi.usra.edu/education/explore/ice/background/allAboutWater/index.shtml
http://www.chem1.com/acad/sci/aboutwater.html
http://www.middleschoolchemistry.com/multimedia/chapter2/lesson2#models_of_water_mol
ecules
Student Worksheet for Density Comparison of Water and Ice
Experiment Title: ______________________Date: __________Name: _____________
Student Hypothesis: _____________________________________________________
Materials: _____________________________________________________________
Procedure: ___________________________________________________________
1. ___________________________________________________________________
2. ___________________________________________________________________
3. ___________________________________________________________________
4. ___________________________________________________________________
5. ___________________________________________________________________
6. ___________________________________________________________________
Data:
Graduated cylinder (grams)
Graduated cylinder + water (grams)
Graduated cylinder + ice (grams)
Mass of water (grams)
Volume water (ml)
Mass of Ice (grams)
Volume ice (ml)
Results:
Density of Ice
Density of Water
Observations: __________________________
1. ___________________________________________________________________
2. ___________________________________________________________________
3. ___________________________________________________________________
Conclusion: _______________________________________________________________
_________________________________________________________________________