Sunday, March 31, 2013

pH Exploration

The Thursday before Spring Break, the River Spies learned more about the pH of different substances and practiced some water quality testing techniques.
Determining the pH of a common household item.

pH Exploration
pH stands for "the power of hydrogen". On a scale from 1-14, one represents the most acidic and fourteen represents the most basic. Pure water has a pH of 7.0. Most aquatic animals live in water with a pH range of 6.5-8.2.

We tested the following substances of varying pH: lemon juice (2), milk (6.5), water (7), baking soda (8.5), and soap (10.0).

Water Quality Testing
The River spies noted the temperature of hot and cold tap water in degrees Celsius. We then measured the amount of dissolved oxygen (% saturation) in the water samples.
Note: Cold water can hold more dissolved oxygen than hot water!

These techniques will be put to good use after Spring Break when we test the water quality at another Amazon Creek site.

Tuesday, March 19, 2013

Water Pollution

This past week we focused on water pollution
We asked and answered several questions: Where does pollution come from? Can we see all contaminants with the unaided eye? How do pollutants affect eggs and nesting animals? Where does the storm water from Edison's campus go?


The kids already knew a fair amount about potential water contaminants. 
They identified fertilizers, pesticides, motor oil, pet waste, detergents, litter, and excessive dirt as sources of water pollution.

Storm drain with leafy debris

After the River Spies had mentioned motor oil as a contaminant, we conducted an experiment to test how eggs (hard boiled) faired when immersed in oil (cooking oil). We peeled an egg after 5 minutes and then one after 15 minutes. The oil soaked through the porous shell membrane and coated the inside of the eggs. The shell of the egg that soaked for over 15 minutes was already soft and disintegrating! 
The kids could easily relate the results of our experiment with the devastating effect motor oil can have on ground nesting animals.

Examining an oil soaked egg

The River Spies had a rare opportunity to "taste" an experiment in which invisible "pollutants" were dissolved in tap water. I added lemon juice, salt, and sugar to various cups and had the kids sample the mixtures. This simple demonstration introduces the fact that not all pollution can be seen. Clear water is not necessarily clean water!

A downspout - DING! DING!

At the end, we toured the perimeter of Edison Elementary school grounds. The air reverberated with a rousing "DING! DING!" every time the River Spies spotted a downspout, storm drain, or source of water pollution.  

Storm drain with litter and an oil sheen.

Sunday, March 10, 2013

Aquatic Macroinvertebrates

Last Thursday, the River Spies sampled for aquatic macroinvertebrates in Amazon Creek. Macroinvertebrates are animals that lack a backbone and can be seen with the unaided eye. "Aquatic" refers to animals that spend most of their lives associated with bodies of water. These animals are excellent bioindicators - their presence, abundance, and diversity can indicate the health of a stream, river, lake, wetland, or other aquatic environment. Macroinvertebrates are grouped according to their tolerance to pollution. 

At Amazon Creek, we turned over rocks, scanned the water, 
and scoured the stream banks in search of any life. 

Some of what we found:

Mayfly Larva (2)
Sensitive or Intolerant to Pollution
Water Strider (1)
Tolerant of Pollution

Leeches (20+)
Tolerant of Pollution

Overall, our Amazon Creek site rated as having poor water quality.
A link to StreamWebs™  - an online water quality data base managed by OSU. 
I loaded our results from 3/7/13. 

Saturday, March 2, 2013

Water Filters and Capillary Action

This week we dispelled some misconceptions about where Amazon Creek is versus Amazon River. Next week, we will be visiting Amazon Creek in Eugene, Oregon not Amazon River in South America!

The River Spies created their own water filters out of soda bottles, coffee filters, sand, and gravel. We tested each water filter's ability to clean "dirty" water. This activity allowed the kids to observe filtration rates through different types of soil and to witness soil's capacity for trapping pollutants.

Here are all the Kinder River Spies with their water filters: 











I also passed around celery stalks that had sat in red food coloring overnight. 
The kids observed that the celery sucked up the water like a straw (capillary action). 
We will link this concept to the importance of vegetation near waterways - 
plants absorb and retain water along with pollutants.
If you want to repeat this activity, follow this link: