Nanotechnology and Water Quality
Authors: Adria Hughes, Galeet Cohen
Standards (PA): 3.1.10A-B, 3.1.10D (systems and feedback, system redesign, modeling, scale)
4.2.10 B-C, 4.3.10.A-B, 4.8.10.A-D, 4.9.10A (env health, cost benefit, laws)
- Differentiate between types of pollutants (biological, heavy metal, pharmaceutical
- understanding of water crisis causal issues
- the consequences of poor water quality include poverty, economic depression, health
- geographic and political scope of the water crisis (quantitative)
- use of filters to clean water
- **unique properties of nanoscale in creating better filters
Day 1: Leading questions & discussion, Intro to water crisis issues, scale of pollutants sorting activity
Day 2: filtration inquiry: What are the characteristics of a successful water filtration system?
Day 3: The science of nanofilters and empirical comparison of nano and conventional water filters.
Day 4: Reflection/extension
If this river were your main water source:
- What would you need this water for?
- What pollutants are present?
- For each type of pollution…
What is the probable source?
What are its health implications?
How can it be treated/removed it?
Procedures (in slightly more detail):
1. Selected powerpoint slides (see attached powerpoint)
a. What do we use water for?
b. How much of the water on the planet is available for human consumption?
c. How is available freshwater endangered by pollutants?
d. How is the freshwater on earth distributed among the population?
2. Pair activity: sort various water related items (bacteria, viruses, heavy metals, drug compounds, silt, water drop) by size
Scale of Filtration (see attached PDF)
a) Provide students with images of common water contaminants (bacteria, viruses, heavy metals, proteins- ask them to guess about the relative size of each item and to place it along a clothesline continuum.
b) Review of nanoscale (how big IS a nanometer?) practice of conversions
c) Web research
a. actual size of each item
b. reasons why it poses a health/aesthetic threat
d) Revise clothesline
e) Expectations for conventional and nanofilters based on published capabilities
3. Share results
4. Preview tomorrow’s lab
1. Inquiry Lab- natural filtration w/ sand, gravel, charcoal etc.
a. Competition to have “cleanest water”
b. Compare filtered water from each group. Determine a “winner” compare methodology.
2. Wrap-up: consider question “would you drink the water?” “ what else might still be in it?” preview tomorrow’s lab testing nano-filters against brita filters.
Homework: (Groups should divide the research among members)
Research the chemicals we’re testing for tomorrow (nitrate, nitrite, calcium, iron, hardness, copper) as well as the following (arsenic, mercury, lead, chromium) and the following microorganisms (giardia, cholera, amoeba).
a. list the source (both natural and anthropogenic – as applicable)
b. problems associated with each (environmental health, agriculuture, etc),
ec: note specific places in the world where that contaminant problematic. Be sure to cite references accurately for credit.
1. Intro presentation: how the filters work (see powerpoint)
2. Testing brita against nano
3. Share data (class averages etc) and discuss conclusions, affordances and constraints of each technology type.
What water pollutants could this fellow have unknowingly caught along with these items? Include 5 and place them in order from largest to smallest. Include one health concern along with each.
Cost Benefit Analysis
1. Read about LifeStraw
http://www.vestergaard-frandsen.com/lifestraw.htm (especially the brochure pdf)
2. Discussion questions:
- what characteristics are needed in a filter meant for the most needy world populations?
- Why use the filter when there are other methods? (p18-19 of brochure pdf)
- Why aren’t they using nanotechnology?
- Do you think they should use nanoceram style technology (why/why not)