Curriculum Embedded Performance Task
Middle School Science
Content Standard 6.1, 6.2 or 6.4
DIG IN!
Student Materials
Connecticut State
Department of Education
Bureau of
Curriculum and Instruction
Dig In!
A Guided Exploration of
How Water Moves Through Soil
ENGAGE
When you think of soil, you may think of just plain dirt. Look again at the picture of the soil
on the cover. Can you see some
things that are mixed in with the soil?
Are there other materials that are mixed in that are not so easily seen?
EXPLORE
Imagine that your class will be planting a vegetable garden as
part of a study about ecosystems. You need to choose the best location for the
garden, and one of the important factors is the type of soil.
In this activity, you will observe and compare different types of
soil. Then you will investigate
factors that may affect how much water the soils can hold and how quickly water
can pass through them. Finally,
you will apply the results of your investigations to make decisions about the
location of a new garden.
1.
Observe the different soil samples with and without the hand lens. Notice different properties such as
color, grain size, lumpiness, etc. Do you notice anything that is alive or was once alive?
2.
Record your observations in your science notebook. Make an organized list of things you
notice and things you wonder.
3. Identify
a property that may be related to the soil’s ability to hold water. This
property is called “absorbency”. Write a research question that can be
answered by doing an experiment.
Experiment #1 – Relationship Between Soil
Properties and Water Absorption
1.
For each lab group: For
each student: 2-liter plastic bottles 1 liter each of 4 different soil types (in labeled
zip-loc bags) Scissors Piece of fine mesh, panty hose, screen, or cheesecloth Duct tape 500 mL beaker 100 mL graduated cylinder Water Stopwatch or clock
Gather
the
following materials to use in planning and conducting your experiment:
2.
To conduct your experiment, you can make a soil testing
device like the one in the diagram:
a.
bottle
top
Cut the plastic bottle across the
middle. Remove the labels and the
caps. The bottle top will hold the soil, and the beaker (or the bottle bottom)
will catch the water.
b.
Position the mesh near the bottle neck so it will keep the
soil in the bottle top.
c.
Rest
the bottle top, neck down, on the bottle bottom so that water poured through
the soil in the bottle top will flow into the bottle bottom.
3.
Design a procedure that will help you answer your research question. List the steps you will follow in your science notebook. Include enough detail so that anyone
could repeat your experiment.
4.
In this experiment, the dependent variable is the soil absorbency. In your science notebook, record the independent
variable you will investigate and the
variables that must be kept constant in your experiment.
5.
Design a data table to record your findings in your science notebook.
6. Do
your experiment and record your
findings. Do the data seem
reasonable? If not, do you need to
repeat any trials to correct errors?
7. Calculate
the amount of water remaining in each
soil.
8. Interpret
the data. Use your calculations to help you reach a conclusion about
what properties affect soil absorbency (how much water the soil holds).
9. Share
your procedures and conclusions with others in your class. How are they alike? How are they different? What changes could be made to the
procedures to make the results more similar?
EXPLAIN
Investigate Through Research
The food we eat and water we drink, in many ways, depend on the quality of the soil. Do some research in books, magazines or the Internet to find out more about what soil is, where it comes from, different soil types and how wet and dry soils affect an ecosystem.
Write a reflection in your science notebook that explains
your understanding of how the soil type affects what grows in a particular
area.
ELABORATE
Investigating Further
Experiment #2 –
Relationship Between Soil Properties and Water Percolation Rate
In this investigation, you will explore
properties that affect how quickly water moves through different soil
types. This is called the soil’s “percolation
rate”.
1. Observe the
different soils again. What are
your ideas about soil properties that might be related to soil
percolation? Discuss your ideas
with your partners.
2. Predict which soil
type might have the fastest percolation rate based on the properties you
observed.
3.
Write a
procedure that will help to answer your question. To conduct your experiment, you
can use a soil testing device like the one used in Experiment #1. List
the steps you will follow in your science notebook. Include enough detail so that anyone could repeat your
experiment.
4.
Identify the dependent and independent variables in your experiment.
Identify the variables that will be kept constant in your experiment.
5.
Create a data table to record your findings in your science notebook.
6. Do
your experiment and record your
findings.
7.
Think about the data you have collected. Do the data seem reasonable? If not, do you need to repeat any
trials to correct any problems?
8.
Analyze the data.
Calculate the average time it took for the water to move through each of
the soils.
9.
Interpret the
data. What conclusions can be made based on your data?
10. Share your procedures and conclusions with others in your
class. How are they alike? How are they different? What changes could be made to the
procedures to make the results more similar?
Possible Variations/Extensions (optional):
Some plants prefer moist soil, while others prefer dry soil. You may want to find out if a soil’s moisture content can be changed by experimenting with different soil combinations.
Applying Your
Findings To Solve A Problem
Imagine that you are
going to plant a vegetable garden at your school or at home. You need to know what type of soil you
have so you can select the right plants and know how much or how often you will
need to water them. Use what
you’ve learned through your experiments and your research to describe the type
of soil in the school or home sample you have tested.
Communicate Your
Conclusions:
Make a recommendation to the school principal about where the garden should be planted and how much watering it will need. Write an expository report that includes the following:
- An introduction that summarizes your research questions and findings;
- A description of the different soils you observed and how they were tested;
- A description of the school soil type and how it is similar to or different than the other samples you tested;
- A recommendation about whether the school garden should be planted in the area from which you took your test sample; and
- A conclusion that suggests areas for further research needed before planting the school garden.