For StudentsEngineering Design in Oregon Science ClassroomsPage 1 of 4

Name ______

Engineering Design Handout for Bioswales

Scenario: You are an environmental engineer who has been hired to design bioswales for a major city in Oregon.

Problem: Identify the problem(s) your bioswale design should address.

Criteria: What should your bioswale be able to do?Be specific.

Priorities: Rank the criteria you identified above in order of importance. Be sure to explain you rankings.

Constraints: What might limit your ability to build a bioswale? What might limit the effectiveness of the bioswale you build?

Solutions: Using what you learned from the water filter research activity, sketch two different design ideas for your bioswale water filter in the space provided on the next page. Be sure to label all the parts of your filter in your sketch and include the quantities you plan on using. Below are some questions to consider as you brainstorm ideas:

  • What materials do you want to use, and in what order?
  • Do you want to mix any materials?
  • How much of each material should you use?
  • How are you going to layer your materials? Will you put everything in one container, or will you separate materials by stacking containers?
  • Does the number of filtrations affect the water quality? In other words does the water get cleaner the second time it is put through the filter?

Solution Ideas

Solution One / Solution Two

Build: Chooseone of your solutions to build first and show that solution to your teacher. Once you have his or her approval, gather the materials you need and start building your solution. If you make changes as you build, be sure to update your original sketch as well (so you have an accurate record for future reference). Your final solution will be built multiple times. Your description must be accurate and detailed, so your trials are all consistent.

Test: Test your design in the same way that you did your research tests.

  1. Get 150 ml of the dirty water solution.
  2. Record the initial turbidity of the dirty water in Table #1. To measure turbidity you will use a graduated cylinder and the picture of the Secchi at the end of this packet.
  3. Measure, then record the initial pH of the dirty water in Table #2.
  4. Place your plastic filter in a beaker.
  5. Stir the contaminated water until its contents are evenly distributed, then pour all 150 ml into your filter. Start the timer once all the water has been poured. When 100 ml of water has collected in the beaker below, stop the stopwatch and record the infiltration time inTable #3.
  6. Let the remainder of the water filter. Record your observations of the filter in Table #4.
  7. Measure the turbidity of the filtered water and record in Table #1.
  8. Measure the pH of the filtered water using a pH Strips, compare the color of the strip to the color key and record the pH in Table#2.
  9. Dump your water solution in the sink and discard the dirty filter materials in the appropriate place. Wash out your plastic container, pipette, beaker and graduated cylinder.
  10. Rebuild your filter in the exact same way as before. Do not change your filter design yet.
  11. Repeat steps 1–10 two more times, for a total of three trials.
  12. Repeat steps 1–11 using your second filter design.
  13. Find your average time, turbidity, and pH by adding up your three trials then dividing by three. Record the averages in the appropriate tables.
  14. Subtract the initial turbidity from your average final turbidity to determine the average change in turbidity. Record the result in Table #1.
  15. Subtract the initial pH from your average final pH to determine the average change in pH. Record the result in Table #2.
  16. Record your results on the class data sheet.
  17. Clean up and return materials.

Data Table #1: Turbidity

Solution / Initial Turbidity (ml) / Final Turbidity (ml) / Change in Turbidity (ml)
Trial 1 / Trial 2 / Trial 3 / Average
1
2
3
4

Data Table #2: pH

Solution / Initial pH / Final pH / Change in pH (ml)
Trial 1 / Trial 2 / Trial 3 / Average
1
2
3
4

Data Table #3: Infiltration Time

Solution / Infiltration Time (seconds)
Trial 1 / Trial 2 / Trial 3 / Average Time
1
2
3
4

Data Table #4: Observations

Solution / Observations
1
2
3
4

Redesign: How well did your filterperform? How could its performance beimproved? Time permitting, use the data you’ve collected and the observations you’ve made on your first two filter designs to brainstorm, sketch, build, and test one or two more filters.

Redesigned Solution Ideas

Solution Three / Solution Four

Evaluation: Write two paragraphs on a separate sheet of paper, which evaluate the effectiveness of your water filter design solutions.

Your first paragraph should address the following questions:

Which of your designs was the most effective in terms of criteria, priorities, and constraints?

What is a trade-off associated with water filter design?

How did your filter design deal with this trade off?

You second paragraph should identify possible design improvements to your best filter. For this paragraph you may think beyond the constraints that restricted you in this activity.