Robin Marks
Founder Discovery Street
Science

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Water That’s Safe to Drink
Goal:
Students learn about water quality and the role of engineers in maintaining it. Working in teams, they practice water quality assessment by measuring turbidity before and after passing water through a filter prototype that they’ve made.
Engineering/STEM areas:
Mechanical engineering, environmental engineering, properties of materials

Water That’s Safe to Drink
Learning objectives
• Understand the concept of water quality and how it is measured
• Learn about the role engineers play in addressing water quality issues
• Understand turbidity and how a Secchi tube turbidity meter works
• Design and evaluate a prototype water filter
• Make connections between environmental science and engineering

Water That’s Safe to Drink
Time:
60 mins
Suggested group size:
3-4 depending on budget and number of students
Materials:
• Dirty water from a nearby natural source (lake, stream, etc.). Approx. .5 L/group
• One clean container to hold at least .5L (per group)
• One clean, empty 2L soda bottle (per group)
• Funnel
• For the Secchi disk turbidity meter (one set for each group of students):
• One-half a fluorescent tube light cover WITH ENDCAP (about 4 ft. long)
• Lid from white plastic container
• Scissors
• Black permanent marker
• Putty, electrical tape, or quick drying sealant
• Meter stick

Water That’s Safe to Drink
Materials (continued):
• Student Resource Sheets (in lesson)
• Student Worksheets (in lesson)
• Materials for filtering, such as:
• Sand
• Aquarium gravel
• Sponges
• Cotton pads or batting
• Coffee filters
• Thick paper towels
• Panty hose
• Rubber bands
Have enough of these materials so that all groups have some to use

Water That’s Safe to Drink
Before the activity:
• Read through both the student and instructor resources so you have the background information
• Gather all the necessary materials. Assemble sets of materials for each group
• Make enough copies of the Student Resource so that each student has one
• Make one copy of the Student Worksheet per group, plus a few extras
• Make your own set Secchi disk meter and plan to demonstrate it
• Make your own filter prototype and demonstrate it.
• Collect water from a natural source such as a river or lake. Collect 500 ml for each group of students.

Water That’s Safe to Drink
Engineering clean water
Access to clean water is vital to the survival of any society. Over the last few centuries, engineers have greatly improved the quality and increased average lifespans in industrialized countries by developing ways to purify and deliver clean water to a large population. http://il-elgin3.civicplus.com/
Many people in developing countries aren’t lucky enough to have a reliable, clean water supply. Each day, 6000 people in the world die because of contaminants in their water. Engineers are working hard to design devices that individuals can use to purify water and infrastructure that poorer nations can afford and that can draw on local resources.

Water That’s Safe to Drink
What is water quality?
When we say “water quality,” we’re referring to a set of indicators. Among them are:
• Turbidity is the clarity or cloudiness of the water. High turbidity indicates lots of suspended particles, a sign that the water is not clean.
• Dissolved metals occur naturally but can reach much greater concentrations when metal-rich waste water is discarded in a lake or stream.
• Microorganisms also occur naturally in water, but some microorganisms, such as E. coli usually enter water as part of the stream of human or animal waste.

Water That’s Safe to Drink
Cleaning up
The first step in cleaning up water is measuring the levels of contaminants that need to be removed. Engineers will often measure turbidity of the water when they start, and then design a water treatment process, and measure turbidity afterward to see how well the process cleans particles from the water.
epa.gov

Water That’s Safe to Drink
Cleaning up (continued)
The most common water treatment process for a municipal water supply follows five steps:
1. Removing large particles with a filter or by letting them settle.
2. Bringing bacteria and other particles together clumps called flocs, that will settle and be removed
3. Filtration to remove bacteria, algae, and small flocs that remain
4. Chlorination to destroy remaining pathogens
5. Aeration to improve taste and odor http://wps.prenhall.com/

Water That’s Safe to Drink
Activity procedure
• This activity begins with a K-W-L chart (Know/Want to Know/Learned) that serves as an assessment. Explain that students will be learning about water quality. Ask students what they think “water quality” means and how they would assess that.
• Fill answers in the “K” column of the K-W-L on a white board, or have them fill in their own copy (included in the Student Resource).
• Go over the information in the Student Resource, explaining the indicators that are measured to determine water quality. Make sure that students understand the concept of turbidity and what it indicates.

Water That’s Safe to Drink
Activity procedure (cont’d)
Demonstrate the Secchi tube turbidity meter (instructions are in the Instructor
Resource). Be sure to describe and explain what you are observing, and give students a chance to look down the tube.
• Distribute materials to build Secchi tube and 500 ml of water from a natural source to each group of students. Give them 10 minutes to put the meter together and take an initial measurement of the turbidity of the water
• Lay the filter materials out so that students have access to them.
• Show students your filtration prototype and demonstrate it. Then allow groups about 10 minutes to browse the materials they can use in their filter prototypes.
During this time, groups should come up with a plan or drawing for their prototype and record it on their worksheet.

Water That’s Safe to Drink
Activity procedure (cont’d)
• Give each group of students a 2L bottle and scissors. Allow about 15 minutes groups to build their filter according to their planned design and measure turbidity after filtration.
Circulate around the room to keep students on task and make sure they record their results.
• When you have about 10 minutes left, ask groups to report their findings.
Each group should also include something to put in the “L” column of their K-W-L chart that describes something that they learned.

Water That’s Safe to Drink
Building the Secchi tube turbidity meter
• Start with one-half length of fluorescent light cover (about
120 cm) with an endcap. Remove the endcap and cut a circle that will fit inside it from the plastic container lid.
• Draw the checkered pattern shown on the circle, and place it facing up in the endcap. Replace the tube into the endcap. If the seal is not tight, seal it with putty, electrical tape, or sealant.
• Mark off 10-cm measurements on the tube.
• Pour your water sample into the tube slowly, stopping to look down the tube and note whether you can still see the checkered pattern.
• When you can’t see the checkered pattern anymore, note the cm measurement on the tube.
Image: lakeaccess.org

Water That’s Safe to Drink
Making the water filter
• Cut the top third off of a 2L plastic water bottle.
• Invert the top. Fill it with filtering material.
• Be sure to create a way to keep the filter from flowing out of the bottle. This could be putting a screen, filter, or nylons at the bottom opening and securing it with a rubber band.
• Pour the water sample into the filter and let it drain into the bottom half of the bottle.
• Sample this effluent for turbidity.
www.h2ouniversity.org/

Water That’s Safe to Drink
Assessment: K/L/W chart
• When students report their findings, ask to describe what they noticed as they constructed and used their filters and took measurements
• Ask each group what they put in the “L” column of their K-W-L chart. Record these on the white board if you are using one.
• Ask each group to the following questions:
• What contaminants might still remain in the water that you can’t see?
• How could you improve you water filter?
• How will your filter be affected by use over time?

Water That’s Safe to Drink
Vocabulary
• Water quality – A measurement of physical, chemical, and biological indicators in water. Indicators such as dissolved metals, turbidity, and microorganisms, among others.
• Effluent – The fluid leaving a system after being treated
• Influent – The fluid entering a system to be treated
• Potable– Water that is safe for drinking
• Turbidity – A measurement of the cloudiness or haziness of water caused by suspended particles
• Pathogen – A disease-causing organism

Water That’s Safe to Drink
Extensions
• Have students design a two-step filtration process, one that removes large particles first, then fine particles.
• The water filters students have created are good for what’s called point-of-source filtration. This is very useful for communities that don’t have a reliable water infrastructure. Tell students to devise training and instruction for people who might need to use a point-of-source filter. The instruction should include how to maintain the filter over time and use. Students can either demonstrate their training or write up training documents.

Water That’s Safe to Drink
Teaching tips
• Take the reins on dividing the class into student groups (rather than letting students decide). If you know your students, try to be sure that each group has a balance of personalities, with a mix of outgoing and more introverted students.
• Circulate around the classroom as students are working and be sure to keep them on track, answer questions, and encourage students who are less assertive.
• Some groups will be more active and will immediately start experimenting, while others will be more reticent. Demonstrate how the Secchi meter and homemade filter work to prompt student engagement.
• Encourage students to think about the challenges of designing water filtration that can function well in different climates and without electricity. Tell them to think about who might find their filter useful, and if there’s a way to scale their filter to make it work for a whole community.
• Remind students that engineering design is a process involving prototypes and improvements.

Water That’s Safe to Drink
Takeaways:
• Engineering to solve environmental challenges:
Students consider the roles engineers can play in the provision of clean water resources
• Environmental engineering as a field of engineering:
Students connect engineering practice to assessing and navigating real-world environmental problems
• Water quality management:
Students understand what water quality is and how it can be monitored and improved on both a large and small scale.

Water That’s Safe to Drink
Resources and bibliography:
Making a Secchi Turbidity Meter: http://www.cas.umn.edu/assets/pdf/Turbidity%20Tube.pdf
https://www.teachengineering.org/collection/cub_/activities/cub_waterqtnew/cub_wat erqtnew_lesson01_activity1_howtomake_tube_jly_tedl.pdf
What is Turbidity and Why is it Important?
http://water.epa.gov/type/rsl/monitoring/vms55.cfm
Test and Treat Before You Drink: https://www.teachengineering.org/view_lesson.php?url=collection/cub_/lessons/cub_w aterqtnew/cub_waterqtnew_lesson01.xml
Save a Life, Clean Some Water: https://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/cub
_waterqtnew/cub_waterqtnew_lesson01_activity1.xml
National Geographic: Earth’s Freshwater http://education.nationalgeographic.com/education/media/earths-fresh-water/?ar_a=1

Water That’s Safe to Drink
Questions about the activity?
Contact Robin Marks
Discovery Street Science discoverystreetscience@gmail.co
m

• Introductions/Icebreakers
• Six elements of communication
• Nonverbal communication
• Communicating your college and career goals
• College and scholarship essay tips
• Elevator speeches
• Wrap-up

Six Elements of Communication
SOURCE
ENCODE

Six Elements of Communication
▪
– The person who is communicating or originating the message
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– Verbal communication
– Nonverbal communication

Nonverbal Communication
Percentage of Communication
38%
55%
7%
How You Speak Words Nonverbal Communication

Six Elements of Communication
SOURCE
ENCODE
MESSAGE

Six Elements of Communication
▪
– What needs to be communicated
– Words matter, choose them wisely
– Repeat important points/concepts three times
– Organize your thoughts logically
– Be direct

Six Elements of Communication
SOURCE
ENCODE
MESSAGE
MEDIUM

Six Elements of Communication
▪
– The means of communication
– Examples include
▪ Written communication
▪ Spoken/oral presentation
▪ Drawings or visual illustration
▪ Text message
▪ E-mail message
▪ Social media
▪ Interactive demonstration
– Consider your receiver’s needs
– Choose the most appropriate channel

Six Elements of Communication
SOURCE RECEIVER
ENCODE
MESSAGE
MEDIUM
MESSAGE
DECODE

Six Elements of Communication
▪
– The person who is receiving the message
▪
– Reading the message and decoding it for meaning and understanding

Six Elements of Communication
SOURCE RECEIVER
ENCODE
MESSAGE
MEDIUM
MESSAGE
DECODE
NOISE

Six Elements of Communication
▪
– Interference from receiving the message
– Distractions
– Emotions
– Affects the effectiveness of communication
– Can be controlled (sometimes)

Six Elements of Communication
SOURCE RECEIVER
ENCODE
MESSAGE
MEDIUM
MESSAGE
DECODE
NOISE
FEEDBACK

Six Elements of Communication
▪
– Response to sender’s message
– May be positive or negative
– Can be verbal or nonverbal
– Helps sender understand how message is perceived

Communicating Your College &
Career Goals

Communicating Your College &
Career Goals
▪
– College applications
– College admission and scholarship essays
– Admission and scholarship interviews
– College and job fair interactions with recruiters
– Interacting with mentors and professionals
– Art portfolio or music audition for art and music majors
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College and scholarship essay tips
1) Answer the question
2) Be original
3) Be yourself
4) Don’t “ thesaurize ” your essay
5) Use imagery and clear, vivid prose
6) Spend the most time on your introduction
Source: MBA 360 (www.mba360.com/mba-essays.html

College and scholarship essay tips
7) Body paragraphs must relate to introduction
8) Use transitions
9) Conclusions are critical
10)Do something else
11) Give your draft to others
12)Revise, revise, revise
Source: MBA 360 (www.mba360.com/mba-essays.html

College and scholarship essay tips
▪ Follow the formatting and word limit instructions
▪ Submit the essay by the published deadline
▪ Ensure you submit the essay in the appropriate file format

Activity: College/Career
Elevator Speech

Elevator speeches
▪ A quick speech or pitch to sell and idea, promote your business, or market yourself as an individual
▪ Usually takes only about 30 seconds but can be slightly longer
▪ For this activity, use the handout to prepare a 30-45 second elevator speech about your college and career goals
▪ Partner up with someone else and take turns practicing your elevator speech

Elevator speeches
CONGRATULATIONS on completing your elevator speeches!
Use today’s activity as a starting point for a college or scholarship essay.
Find help editing and preparing your essay from your teachers, counselor, or mentors.

Summary
▪ Effective communication involves
– Developing a clear message
– Consideration of nonverbal cues
– Choosing the most appropriate channel for delivery the message
– Adjusting for noise
– Looking for feedback
▪ College essays must be compelling and well thought out
▪ Take time to develop a creative introduction and relevant body paragraphs
▪ It is important to follow directions and submit the application on time

Thank you for attending!

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