Dirt in the Water

 

Purpose/Rationale

            The purpose of the lesson is to investigate the effects of erosion using the 5E learning model.  By participating in discrepant events students will explore the effects of erosion onto oxygen availability and aquatic organisms.  Students will gain an understanding of the causes of erosions and its effects. 

 

Standards:

Virginia Standards of Learning:

LS.1     The student will plan and conduct investigations in which

            b)    variables are defined

            j)     an understanding of the nature of science is developed and reinforced

LS.4     The student will investigate and understand that the basic needs of organisms must be met in order to carry out life processes. Key concepts include

b)    animal needs (food, water, gases, shelter, space); and

            c)    factors that influence life processes

LS.12   The student will investigate and understand the relationships between ecosystem dynamics and human activity. Key concepts include

d)    population disturbances and factors that threaten or enhance species survival;

e)    environmental issues (water supply, air quality, energy production, and waste

       management).

 

National Science Education Standards:

TEACHING STANDARD B:
Teachers of science guide and facilitate learning. In doing this, teachers

            a)    Focus and support inquiries while interacting with students.

            b)   Challenge students to accept and share responsibility for their own learning.             c)    Recognize and respond to student diversity and encourage all students to                              participate fully in science learning.

            d)    Encourage and model the skills of scientific inquiry, as well as the curiosity,            

                   openness to new ideas and data, and skepticism that characterize science.

TEACHING STANDARD E:
Teachers of science develop communities of science learners that reflect the intellectual rigor of scientific inquiry and the attitudes and social values conducive to science learning. In doing this, teachers

            a)     Nurture collaboration among students.

            b)    Display and demand respect for the diverse ideas, skills, and experiences of                              all students.

CONTENT STANDARD C:
As a result of their activities in grades 5-8, all students should develop understanding of

            a)    Populations and ecosystems

 

 

 

 

Materials and Resources

For each group of students:

A clear plastic 1-gallon container

Enough pea-sized gravel to cover the bottom of the container to 1 inch from the top

1 cup of coarse sand

1 cup of silt (silica from a stream edge)

3 straws per group member

Paper towels

Source of water

Activity Sheet

 

Safety

Students should take special care not to swallow any water when blowing bubbles through the straw.

 

Procedure

Time frame: one 45-50 minute class period

Engage:

1)      The teacher will ask the students how much of our nation’s water is not fishable, swimmable or drinkable because of pollution.  Advise the students after their guesses that it is approximately 40% of our nation’s rivers, lakes and estuaries that is not fishable, swimmable or drinkable. (2 min)

2)      The teacher will ask and discuss the students how they think a lot of these pollutions get into the waterways.  (3-5 min)

 

Explore:

3)      Students will be divided into small groups, preferably 5-10 students per group.  Ask each group to gather the materials needed for the demonstration, or provide the materials to each group. (1 min)

4)      Ask the students why oxygen is important to aquatic organisms.  Ask the students what possible substances can get into water to “take up” oxygen used by aquatic organisms. (5-8 min)

5)      The teacher will explain the procedure below (steps 6-12) and ask the students to predict what will happen as each sediment type is added to the water onto their activity sheet.  Advise the students that the bubbles represent how oxygen moves through water in different situations. (3 min)

6)      Add a thin layer of gravel and also fill the container about 2/3 with water.(1min) 

7)      About 3-4 students in the group should simultaneously blow bubbles into water with a straw.  The straw needs to be at or near the bottom of the container so that end is pushed into the layer of gravel.  (2 min)

8)      The group will then discuss the ease or difficulty in blowing the bubbles and record observations on the activity sheet. (3 min)

9)      The group will then add one cup of sand to the water and then attempt to blow the bubbles again, being sure that the straw touches the gravel.  (2 min)

10)  The group will then discuss the ease or difficulty in blowing the bubbles and record observations on the activity sheet. (3 min)

11)  The group will then add one cup of silt to the water and allow it to settle.  Once again the group will attempt to blow bubbles through the straw, making sure the straw touches the gravel. (3 min)

12)  The group will then discuss the ease or difficulty in blowing the bubbles and record observations on the activity sheet. (3 min)

 

Explain:

13)  The group will then discuss what how the sediments get into our waterways and what implications this could have on aquatic organisms.   The teacher will explain how erosion contributes to sediment polluting the water.  The teacher will ask the students what the differences are between surface erosion and mass erosion. (10 min)

 

Elaborate:

14)  The teacher will then ask the students what causes erosion.  (5-10 min)

15)  The teacher will then ask the students to point out any examples of erosion around their area. Ask the students what they believe caused this erosion to occur. (5 min) 

16)  The teacher will then ask the students how erosion connects with the polluted waterways of our nations and what they can do to prevent erosion. (3 min)

 

Evaluate (assessment):

Performance Criteria

Evidence

Points

Students should develop a hypothesis on the addition of sediment and oxygen availability.

Completion of the “Erosion” activity sheet.

 

Students should be able to explain the relationship between erosion and its effect using their collected data.

Completion of the “Erosion” activity sheet.

 

Students should discuss potential causes and effects of erosion.

Discussion of their conclusions

 

2 = completes activity and explanation without mistakes

1 = completes activity but offers incomplete explanation.

0 = does not complete activity or explanation

 

 

This activity is modified from Silt: A Dirty Word from Project Wile Aquatic: K-12 Curriculum and Activity Guide by the Council for Environmental Education, 2003.