Watersheds, Water Quality & Sampling Limits — Practice · Grade 6 Science
Chapter: Ecosystems, Watersheds & ConservationWhat this practice covers
By the end of Watersheds, Water Quality & Sampling Limits you should be able to:
- I can explain what a watershed is and why upstream land use affects downstream water.
- I can explain what dissolved oxygen indicates and what lowers it.
- I can state what a single water sample can and cannot establish.
8 questions, written answer and multiple choice, each with a worked explanation.
Vocabulary used: watershed, turbidity, evidence, system boundary, uncertainty.
Problem 1
Answer and explanation
It identifies a possible pathway, while other sources, events, and transport conditions require evidence.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 2
Answer and explanation
No. Visual clarity cannot establish removal of microbes or dissolved contaminants; this course does not conduct drinking-water certification.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 3
Answer and explanation
Time, exposure, method, depth or position, weather context, and repeated samples relevant to the question.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 4
Answer and explanation
The measurements and standards needed differ. A limited classroom indicator set cannot establish every microbial or chemical safety requirement.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 5
Answer and explanation
A’s mean dissolved oxygen is 8 mg/L; B’s is 5 mg/L. A has lower recorded turbidity under the stated method. These indicators support different physical/ecological comparisons, but the small record does not identify every cause, represent all seasons, or certify either water as safe to drink.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 6
Answer and explanation
No. Missing measurement is not measured zero. Preserve the absent entry and obtain a comparable record if the question requires it.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 7
- One sample represents every place, season, and water-quality property.
- Clear-looking or filtered water is automatically safe to drink.
- watershed: An area whose drainage connects toward a common outlet under a defined landscape model.
- One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation
watershed: An area whose drainage connects toward a common outlet under a defined landscape model.
An area whose drainage connects toward a common outlet under a defined landscape model. A’s mean dissolved oxygen is 8 mg/L; B’s is 5 mg/L. A has lower recorded turbidity under the stated method. These indicators support different physical/ecological comparisons, but the small record does not identify every cause, represent all seasons, or certify either water as safe to drink.
Problem 8
- One illustrative result establishes every real condition and needs no further evidence.
- Clear-looking or filtered water is automatically safe to drink.
- One sample represents every place, season, and water-quality property.
- turbidity: A measure of water cloudiness associated with suspended material under a stated method.
Answer and explanation
turbidity: A measure of water cloudiness associated with suspended material under a stated method.
A measure of water cloudiness associated with suspended material under a stated method. A’s mean dissolved oxygen is 8 mg/L; B’s is 5 mg/L. A has lower recorded turbidity under the stated method. These indicators support different physical/ecological comparisons, but the small record does not identify every cause, represent all seasons, or certify either water as safe to drink.