DO-IT-YOURSELF ICEBERG SCIENCE

DO-IT-YOURSELF ICEBERG SCIENCE
OVERVIEW: In this inquiry-based lesson, students will experiment with
their own film canister “icebergs” to explore principles of floating icebergs
and ice density.
Ohio Science Content Benchmarks and Indicators addressed:
6-8: Inquiry A. Explain that there are differing sets of procedures for guiding
scientific investigations and procedures are determined by the nature of the
investigation, safety considerations and appropriate tools.
6.1 (Doing Scientific Inquiry):
Explain that there are not fixed procedures for guiding
scientific investigations; however, the nature of an
investigation determines the procedures needed.
6.2 (Doing Scientific Inquiry):
Choose the appropriate tools or instruments and use
relevant safety procedures to complete scientific
investigations.
7.3 (Doing Scientific Inquiry):
Formulate and identify questions to guide scientific
investigations that connect to science concepts and can be
answered through scientific investigations.
7.4 (Doing Scientific Inquiry):
Choose the appropriate tools and instruments and use
relevant safety procedures to complete scientific
investigations.
8.1 (Doing Scientific inquiry):
Choose the appropriate tools or instruments and use
relevant safety procedures to complete scientific
investigations.
Inquiry B. Analyze and interpret data from scientific investigations using
appropriate mathematical skills in order to draw valid conclusions.
6.3 (Doing Scientific Inquiry):
Distinguish between observation and inference.
7.5 (Doing Scientific Inquiry):
Analyze alternative scientific explanations and predictions
and recognize that there may be more than one good way
to interpret a given set of data.
7.6 (Doing Scientific Inquiry):
Identify faulty reasoning and statements that go beyond the
evidence or misinterpret the evidence.
7.7 (Doing Scientific Inquiry):
Use graphs, tables and charts to study physical phenomena
and infer mathematical relationships between variables
(e.g., speed and density).
9-10: Earth and Space Sciences B. Explain that many processes occur in
patterns within the Earth’s systems.
9.4 (Earth Systems):
Explain the relationships of the oceans to the lithosphere
and atmosphere (e.g., transfer of energy, ocean currents
and landforms).
Physical Sciences C. Describe the identifiable physical properties of
substances (e.g., color, hardness, conductivity, density, concentration and
ductility). Explain how changes in these properties can occur without
changing the chemical nature of the substance.
9.9 (Nature of Matter):
Investigate the properties of pure substances and mixtures
(e.g., density, conductivity, hardness, properties of alloys,
superconductors and semiconductors).
Prior knowledge: Students should be able to define the concept of density
and explain changes in phase of water, especially freezing and thawing.
Materials needed: - Film canisters
- Very cold (ice) water
- Freezer
- Optional: snow (collected when/if it’s around, stored in
freezer)
- Graduated cylinders of various sizes
- Ruler
- Other shapes of freezable container
Procedures:
1. Start with a riddle, maybe taking yes or no questions: What amazing
compound becomes less dense when it changes from solid to liquid?
(water). Discuss implications: ice floats and bodies of water freeze
from top down rather than bottom up, allowing life to exist under
surface. Ask students to describe how freshwater ponds would be
different if ice was denser than water.
2. Show photos of icebergs to students. Many will know (from “tip of
the iceberg” expression) that most of an iceberg is underwater —
discuss what % of an iceberg might be underwater, and if that %
changes from iceberg to iceberg, and what that variation might depend
on (density).
3. Discuss density as a way to measure how well something floats — if
it’s less dense than water, it floats, and the more dense it is, the lower
it stays in the water. Note: starting from this point, students can be
allowed to explore this lab with varying degrees of guidance. You
may choose to allow them to figure out nearly all of their methods
and areas of investigation (creating healthy confusion and some
real inquiry), or give them a very specific procedure, depending
on time constraints.
4. Have students break into small groups. Each group should fill three
film canisters with water, then put them in the freezer (in very cold
weather, they can simply be put outside.)
5. Students remove ice from film canisters, then float their “icebergs” in
extremely cold water in a graduated cylinder small enough so that the
cylinder remains vertical. Obviously there’s a fairly short time
window here before the ice starts really shrinking, so they should
figure out their procedures thoroughly before starting their work.
Very cold water will help keep icebergs from cracking, but for
those that do crack you can use that as an example of calving,
when icebergs or glaciers crack and create smaller icebergs.
6. One way to determine total volume: Note initial volume of water
without iceberg, then submerge iceberg completely by pushing it
down to water-line. The difference in water levels is the iceberg’s
volume.
7. One way to determine % submerged when floating: Simply note
original water level, float iceberg, then note water level with floating
iceberg. Divide volume displaced when floating by total volume from
#6.
8. Explain that icebergs are chunks of ice that have calved from glaciers,
and that glaciers contain ice that has been compressed under high
pressure for thousands of years, increasing its density. Discuss how
real iceberg % submerged might compare to that of their ice.
9. Students should hypothesize what differences they’ll see between ice
and packed snow, and why — then design an experiment to test it.
Snow should be frozen first in canisters, so it doesn’t fall apart in
water.
10. Students should then design their own additional experiments.
Ideas:
• How does packing snow more or less tightly affect %
submerged?
• Do different shapes of icebergs behave differently in water?
For example, does a long, thin tube submerge deeper than a
short, fat one?
• How does ice compare to other substances? Celery? Wood?
Chalk?
•
How does adding salt affect the experiment? Why?