Dynamics ( systems )

Feedback loops

Definition of Flow (Systems)

The Bathtub Model and the Accelerating Imbalance of Atmospheric CO2

The Bathtub Analogy for Wealth, Gross Income, Saving, Consumption, and Depreciation

A city's water supply system is monitored using several metrics. Which of the following metrics describes a quantity measured at a single, specific point in time, rather than as a rate over a period of time?

Identifying a Stock Quantity

Match each of the following quantities with the category that best describes how it is measured. The two categories are: 'A quantity measured at a specific point in time' and 'A quantity measured as a rate over a period of time'.

Interpreting Business Metrics

A financial analyst states, 'Your total student loan debt is a critical indicator because it represents the cumulative result of all your past borrowing and repayments.' Which part of this reasoning correctly identifies the total debt as a stock quantity?

A company's quarterly profit, which measures its earnings over the last three months, is an example of a stock quantity because it reflects the company's financial performance.

Analyzing an Ecosystem Component

An economist is analyzing a country's national forest resources. Four statements are made during the analysis. Which statement makes an error in identifying a quantity's fundamental nature?

A report on a national park's wolf population includes the following data points for a single year: the number of pups born, the number of deaths, the average monthly food consumption per wolf, and the total population size counted on the final day of the year. Which of these data points represents a stock, and what is the reasoning for this classification?

A farmer's grain silo contained 1,000 bushels of wheat on January 1st. Throughout the year, the farmer added 500 bushels from the harvest and sold 700 bushels. The amount of wheat in the silo on December 31st was 800 bushels. Based on this information, which statement best analyzes the role of the 'amount of wheat in the silo' within this system?

Population as a Stock

Inventory as a Stock

Stock-Flow Diagram