Clean Water STEAM Project

Steam Water Filter Designs

Why Care About Water?

Note that I need to give a more careful look at these videos before sharing with students.

Water Facts

The Filter Straw Invention

Introduction

Is it Safe to Drink?

A hands on investigation where students will engineer a method for cleaning water, discover the most effective way to filter water, and practice conducting a scientific experiment. Through this activity students learn the engineering design process related to water treatment, as done by practicing engineers, including constructing and testing their designs.

View complete lesson plan, resources, and curricular units here:

Standard: Grade 5: Earth & Space Sciences. Earth and Human Activity. 5-ESS3-2 (MA) - Test a simple system designed to filter an impurity out of water and propose one change to the design to improve it.

Objective: Students will be able to design and analyze the effectiveness of a water purification filter.

Background/Real World Problem: One of the greatest problems facing society is the availability of clean drinking water. Engineers work in teams to create and test solutions to problems, following the steps of the engineering design process. To provide communities with safe drinking water, engineers design wastewater treatment plants and distribution systems that include sediment filters and chemical treatments to protect public health.

In general, filters perform best when the material porosity graduates from the bottom to the top by the smallest to the largest openings that the water can pass through (for example, placing gravel as a first layer and a coffee filter as the last material layer.) This helps to keep the smaller openings unclogged by filtering out the larger particles in the water first, at the beginning of the process. (don’t share this with students until final discussion, unless necessary.)

Engineering Design Plan:

Ask
Imagine
Create
Plan
Improve

Engineering Design Challenge

After a plane crash somewhere over the Amazon, you and your flight crew are lost and have few supplies. After several days lost in the rainforest, surviving on plants and insects, you quickly start to realize that you are almost out of water. In addition, your pilot is in dire need of medical attention, so time is not on your side. According to your map, there are several pools of water nearby, but you know you will need to filter it before drinking it to assure it is safe to drink. You and your team need to design and engineer an idea for a water filter. What will you use? Will it work?

Activity: Students will use their engineering knowledge to find a way to filter the dirty water that they have been given. They will build and test a water filter of their own design using the materials provided to them. Students will be placed into groups of 3-4 before the challenge.

Procedure

Before the Activity (Teacher)

Get Volunteers to help out.
Sign out Cafe Space.
Gather materials and make copies of the Student Guide Worksheet.
Prepare the plastic bottles. Use scissors to cut the bottom off the 2-liter bottle. Use masking tape to cover the resulting sharp plastic edge, to protect students. Remove any labels from the 2-liter bottle. Repeat this procedure on the rest of the 2-liter bottles for the teams.
Make a class supply of "dirty water." Fill the gallon bottle three-quarters full with water. Use potting soil to fill the remaining one-quarter. Shake the bottle. Then shake it again a few minutes before the activity since the soil will settle after time. A gallon of water is more than sufficient for the entire class.

With the Students

Review with students the scenario provided in the engineering problem.
Pass out the worksheets and materials to groups and review the procedures and guiding questions
Fill each group's empty 12 oz cups with "dirty water." Remind students to never drink this water, even after filtering.
With the worksheet as a guide, have students complete the engineering challenge. Remind them of the basic steps of the engineering design process: understand the need, brainstorm different ideas, select the best design to fit the circumstances and constraints, plan, create and improve.
After answering the worksheet questions, have students turn them in for grading. Lead a class discussion to compare results and conclusions. Students may find that a more "scientific filter" (that is, one using sand and gravel) is slower and does not work as well as one using a coffee filter, or gravel and a coffee filter. Discuss with students their different designs and compare the good and bad points about their filter designs. Example successful points: the filter worked very quickly and the water looked much better than before. Example negative points: the filter took a very long time to filter and did not do a good job of removing particles.

Materials

For the teacher:

1 gallon bottle
1 bag potting soil

Each group needs:

2-liter bottle with base cut off and no cap
2" x 2" piece nylon stocking or cheesecloth
rubber band
4 oz cup course sand
4 oz cup aquarium gravel
small coffee filter
large bowl, approximately 2"– 3" deep
empty 12 oz cup, to be later filled with dirty water
access to a timer or clock

Design:

Students should begin by analyzing their materials, sketching their individual design, and then sharing their ideas with their team. Teams will then decide on one final design that will need to be sketched and labeled. These steps are included as part of the student worksheet.

Build & Test:

Groups will then work together to build their final filter design using the materials they have selected, filter the dirty water, and complete the follow up questions provided in the student worksheet.

Guiding Questions:

Who would want to drink this water?
What might happen if you did drink it?
How could you use the materials provided to you to filter the cleanest water?
What materials should be placed at the top/bottom of your filter?

Reflection & Possible Redesign Questions:

How much water would your team need to purify?
How much water do you think each person on your team will drink? (On average, a person would drink quarts of water per day)
Would you be able to build something like this in the Amazon?
How long would your filter hold up in the Amazon?
What materials would you be able to find in the Amazon?
How did your water change after you filtered it?
What other materials would be helpful?