NYC Water History
What does CSO stand for?
What is Combined Sewage Overflow
What is the chemical makeup of water?
Two hydrogen atoms and one oxygen atom (H₂O)
What is an equivalent ratio?
Two ratios that express the same relationship, like 1:2 and 2:4.
What does “salinity” mean?
The amount of salt dissolved in water.
What is stormwater runoff?
Rainwater that flows over streets and sidewalks instead of soaking into the ground.
Name one way industrial pollution has affected NYC waterways.
Factories and shipyards released oil, heavy metals, and chemicals into the water, making it unsafe for people and wildlife.
What makes a molecule “polar”?
A polar molecule has positive and negative ends because electrons aren’t shared equally.
How can ratios help describe concentration?
Ratios show how much solute (like salt or pollution) is in a given amount of water.
What tool could you use to measure salinity?
A refractometer or a conductivity probe.
Why does stormwater cause problems in cities like NYC?
It picks up trash and chemicals and overwhelms sewers, leading to CSOs.
How do CSOs impact the Gowanus Canal during heavy rain?
When it rains too much, stormwater mixes with sewage, overflows, and dumps dirty water into the canal.
What is cohesion and why is it important for life?
Cohesion is when water molecules stick together. It helps plants pull water up their stems and allows droplets to form.
If 5g of salt dissolve in 100g of water, what is the ratio of salt to water?
5:100 or simplified, 1:20.
How does adding salt change water’s density?
It makes the water denser (heavier).
What can we add to schoolyards to absorb more rainwater?
Rain gardens, grassy areas, trees, or permeable pavement.
Why do older sewer systems cause CSOs?
Older systems collect rainwater and sewage in the same pipes, so when it rains, they overflow.
How does water’s polarity help it dissolve substances?
The positive and negative ends of water attract and pull apart other molecules, dissolving them.
How can proportions help us describe pollution in water?
We can use proportions to predict how much pollution would be in larger or smaller samples.
How does temperature affect salinity and density?
Warm water is less dense and holds less salt; cold water is denser and holds more salt.
How could green infrastructure help reduce CSOs?
It lets rain soak into the ground instead of going into the sewer system.
How has water quality in NYC changed over time due to these issues?
It used to be heavily polluted, but laws like the Clean Water Act and community projects have helped it improve.
Why is water considered the “universal solvent”?
Because it can dissolve more substances than any other liquid due to its polarity.
You test two samples: one has 10g salt per 200g water, the other has 20g salt per 400g water. Are they the same concentration? Explain.
Yes, both are 1:20 ratios (equivalent proportions).
How can you test what happens to water when you add salt and then freeze it? (create an experiment and tell us the outcome, which will freeze first, saltwater or regular water)
Put the same amount of water in two cups. Add salt to one cup but not the other. Place both in the freezer and check which one freezes first. The salty water will take longer to freeze.
How could New York City use technology or data to better manage stormwater and prevent CSOs? Explain your idea.
The city could install smart sensors and monitoring systems in sewer drains to track rainfall, water levels, and overflow in real time.