Chart assignment
Charts to read and discuss
Read each chart, then answer its questions. Every chart shows its source and date; open it for a table of the numbers and the data to download.
Chart 1 of 3 · Climate
How much has the US warmed since 1895?
The interactive chart needs JavaScript. The numbers are on the chart's page.
The contiguous US averaged 54.6°F in 2025. The warmest year since records began in 1895 was 2024, at 55.5°F. Through 2025, the dashed trend line, the straight line that best fits every year, rose about 0.18°F a decade, or 2.3°F since 1895, and warming had sped up to about 0.5°F a decade since 1970. Alaska and Hawaii aren't included.
How to read this chart
Each point is one year's average temperature across the lower 48 states, in degrees Fahrenheit. The axis doesn't start at zero, so a small rise looks steep: read the numbers on the axis, not the height of the line. The dashed line is the trend, the straight line that best fits every year; single years bounce above and below it.
Questions to discuss
- Find the warmest and coolest years on the chart. How many degrees apart are they?
- Why might one year be much cooler than the year before, even while the trend line keeps rising?
- The axis doesn't start at zero here, but bar charts always do. Why is that fair for temperatures but not for bars?
Source: NOAA National Centers for Environmental Information, Climate at a Glance (Public domain (U.S. government work)) · Data as of Dec 31, 2025
Open the chart and its numbersChart 2 of 3 · Crime
Which big U.S. cities have the highest murder rates?
The interactive chart needs JavaScript. The numbers are on the chart's page.
In 2025 St. Louis, MO had the highest murder rate of the 89 biggest U.S. cities whose police reported a full year to the FBI, about 51.3 per 100,000 people, followed by Memphis, TN (31.0) and Cleveland, OH (28.0). Irvine, CA (0.0) and Plano, TX (0.7) had the lowest; the U.S. rate was about 4.4. Departments that didn't report a full year are left out (for 2025, New Orleans, Orlando and St. Petersburg, Florida). Each rate is per person the department serves, and a few, such as Las Vegas, Honolulu, Jacksonville and Louisville, serve their whole county. A city's rate also depends on where its borders fall, so compare cities with care.
How to read this chart
Each bar is the number of murders in a city in one year for every 100,000 people its police department serves. The dashed line is the U.S. rate. Murders are rare, so in a smaller city a handful more or fewer in one year can move its rate and its rank a lot.
Questions to discuss
- How many cities on the chart have a murder rate above the U.S. rate, and how many are below it?
- Why does a chart like this use murders per 100,000 people instead of the total number of murders in each city?
- A city's rank can jump from one year to the next. Why might small numbers make rates bounce around?
Source: FBI Crime Data Explorer, Uniform Crime Reporting Program (Public domain (U.S. government work); source FBI Uniform Crime Reporting Program) · Data as of Dec 31, 2025
Open the chart and its numbersChart 3 of 3 · World
How fast has the world come online?
The interactive chart needs JavaScript. The numbers are on the chart's page.
73.6% of the world's people used the internet in 2025, up from 15.6% in 2005, the first year the World Bank gives a world figure. It counts people who used the internet at least once in the previous three months. The world figures are estimates by the International Telecommunication Union.
How to read this chart
Each point is the share of the world's people who used the internet at least once in the previous three months, as estimated by the International Telecommunication Union. The axis starts at zero, so the height shows the true share. The steeper the line, the faster people were coming online.
Questions to discuss
- About what share of the world was online in the first year on the chart, and in the latest year?
- Did the share grow faster in some years than others? What could have sped it up?
- Using the internet once in three months counts here. What does this number leave out about how people get online?
Source: World Bank, World Development Indicators: Individuals using the Internet (% of population) (CC BY 4.0 (credit the World Bank)) · Data as of Dec 31, 2025
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