Download Matt Knorr October 2013 Summary: Using jars of sediment in water

Matt Knorr
October 2013
Summary:
Using jars of sediment in water, students will observe and verify the nature of sorting. They will
explore factors of density and particle size of common earth materials and and will come to
understand these contributions to the sorted outcome.
Main Curriculum Tie:
Science, 7th grade objective 1: examine the effects of density and particle size on the behavior of
materials in mixtures.
a. Compare the density of various objects to the density of known earth materials.
c. Observe and describe the sorting of earth materials in a mixture based on density and
particle size (e.g., sorting grains of sand of the same size with different densities, sort materials
of different particle size with equal densities).
d. Relate the sorting of materials that can be observed in streambeds, road cuts, or
beaches to the density and particle size of those materials.
Keywords to use:
atmosphere, crust, density, mass, molecule, particle, solid
Student Prior Knowledge:
Students should be able to define and explain what density is and should have a basic understanding
of how it relates the different layers of the earth's interior.
Materials:
For the teacher:
 12 glass mason jars and lids
 6 glass baby food jars and lids
 Sediment samples of varying particle size: fine sand, coarse sand, silt, small pebbles & rocks,
Iron/steel BBs
Intended Learning Outcomes:
1) Use science process and thinking skills.
3) Understand science concepts and principles.
4) Communicate effectively using science language and reasoning.
5) Demonstrate awareness of historical and social impacts of science.
Instructional Procedures:
1) Welcome, review density (2-3 min).
a) d=m/v, dense objects tend to sink, less dense objects tend to float.
2) Discuss density of typical earth materials (air, water, rock, iron metal, etc) and fill out table as a
class. Discuss difference between qualitative and quantitative measurements (3-5 min).
3) Overview of how size/density of particles affects order of deposition. Have students generate
hypotheses on their predicted order of sediment deposition (3-5 min).
4) Quick-lab on sediment settling order and times. Students will be put into small groups to test
individual sediments and mixture's of sediments. After a few minutes of observation,
introduce jars of sediment that have completely settled (only if students' jars don't settle
Matt Knorr
October 2013
quickly). Each group will report back to the group about the settling time of their material.
Either in groups or individually, students will fill out notebook page with table data &
illustration of the observed density column (10-15 min).
5) Engage students in critical thinking trivia if time allows.
Material
State of Matter Particle Size
Density
Mass
Time to settle
Silt grain
Solid
Extremely small ≈ 3 g/cm3
Sand grain
Solid
Very small
≈ 3 g/cm3
Very small
short
Small pebble
Solid
small
≈ 3 g/cm3
small
Almost instant
Small stone
Solid
medium
≈ 3 g/cm3
medium
Iron
Solid
Small
7.87 g/cm3
small
Almost instant
Water
Liquid
-
1.0 g/cm3
-
-
Air
Gas
-
0.00125 g/cm3 -
-
Extremely small long
Critical thinking trivia if time allows
1) How does a particle's size affect how it is moved by water?
2) Which would more easily move larger particles: erosion by wind or a river's erosion by water?
Why?
3) Which would likely be found nearer to the surface of a slow moving stream bed, a flake of Gold
(density 19.3 g/cm3) or a particle of quartz sand (density about 3 g/cm3) of equal size?
Extensions:
Review photographs of sediments seen in road cuts, sediment cores, riverbeds, beaches, etc. and
discuss where certain sediments are likely to be found- streams, lakes deltas, reservoirs, etc. (10-15
min).
Safety Precautions:
Inform students that they are only to shake the jars when instructed to do so. Have them inform the
teacher immediately of any broken glass to ensure proper cleanup.
References:
http://www.uen.org/core/science/sciber/sciber7/stand-2/ (10/14/2013)
http://www.slcschools.org/departments/curriculum/science/Grade-7-to-8/Grade-7/documents/s2-o1lesson-water-sorting.pdf (10/14/2013)
http://departments.jordandistrict.org/curriculum/science/secondary/archive/grade7/70201.html
(10/14/2013)