For teachers

Chart lessons for your class

Each lesson is one chart of trustworthy public data, a short note on how to read it and three questions to discuss. Use them as they are: share a chart's link with your class, post it on your school site, or print this page. Every chart shows its source, its date and a table of its numbers, and students can download the data.

Lesson 1 · Science

How much has the US warmed since 1895?

The contiguous US averaged 54.6°F in 2025, its fourth-warmest year since records began in 1895; 2024 was the warmest, at 55.5°F. The dashed trend line, the straight line that best fits every year, rises about 0.18°F a decade, or 2.3°F since 1895, and warming has 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

  1. Find the warmest and coolest years on the chart. How many degrees apart are they?
  2. Why might one year be much cooler than the year before, even while the trend line keeps rising?
  3. 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 · Data as of Dec 31, 2025

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Link for your class: https://chart.ly/charts/us-average-temperature

Lesson 2 · History

How long do Americans live, and how has that changed since 1900?

A baby born in the US in 2018 could expect to live 78.7 years, up from 47.3 in 1900. The sharpest drop was in 1918, to 39.1 years, during the influenza pandemic. This CDC dataset stops at 2018; later NCHS reports put life expectancy at 78.4 years in 2023 and 79.0 in 2024, after a fall during the COVID-19 pandemic.

How to read this chart

Each point is how long a baby born in that year could expect to live, if death rates stayed as they were that year. It is an average, so it is pulled down a lot when many babies and young people die. Hover or tap a point to read its year and value.

Questions to discuss

  1. Find the sharpest drop on the chart. What happened in the world that year?
  2. Life expectancy in 1900 was under 50. Does that mean most adults died in their 40s? What else could lower the average?
  3. What changes in medicine, food or public health could explain the long rise?

Source: CDC National Center for Health Statistics, Death rates and life expectancy at birth · Data as of Dec 31, 2018

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Link for your class: https://chart.ly/charts/us-life-expectancy

Lesson 3 · Geography

How has the world's population grown since 1960?

The world had 8.22 billion people in 2025, more than 2.7 times the 3.02 billion of 1960. It passed 8 billion in 2023. Figures are mid-year estimates from the United Nations, which revises them as new censuses come in.

How to read this chart

Each point is the number of people alive in the world in the middle of that year, estimated by the United Nations. The axis starts at zero, so the height of the line shows the true size. Look at how steep the line is to see how fast the population grew.

Questions to discuss

  1. Judging from the chart, about how many years did it take the world to add its most recent billion people?
  2. Is the line getting steeper or flatter in recent years? What does that tell you about the growth rate?
  3. These numbers are estimates that the UN revises. Why is it hard to count every person on Earth?

Source: World Bank, World Development Indicators: Population, total · Data as of Dec 31, 2025

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Link for your class: https://chart.ly/charts/world-population

Lesson 4 · Economics

How big is the federal debt compared with the economy?

At the end of fiscal 2025 the federal debt was 124% of a year's GDP, everything the U.S. economy produces in a year. It fell from 96% in 1948 to a low of 32% in 1981, passed 100% in 2013 and jumped to 126% in 2020. This is total debt, including what the government owes its own trust funds, divided by GDP over the same fiscal year; it starts in 1948 because BEA's quarterly GDP starts in 1947, and recent GDP figures are revised.

How to read this chart

Each point divides the federal government's total debt by GDP, everything the U.S. economy produces in a year. At 100%, the debt equals one year of the whole economy's output. Comparing debt with the economy's size, instead of in dollars, makes years decades apart fair to compare.

Questions to discuss

  1. When was the debt smallest compared with the economy, and when was it largest?
  2. The debt can grow in dollars while this percentage falls. How is that possible?
  3. Pick a big jump on the chart. What events could make the government borrow much more in a short time?

Source: U.S. Treasury Fiscal Data, Historical Debt Outstanding; GDP from the Bureau of Economic Analysis (NIPA Table 1.1.5) · Data as of Sep 30, 2025

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Link for your class: https://chart.ly/charts/us-debt-as-share-of-gdp

Lesson 5 · Science

Where does US electricity come from?

In 2025 natural gas made 40.8% of US electricity, followed by nuclear (17.7%) and coal (16.6%). Wind and solar together made 17.2%. Solar counts only utility-scale plants, not rooftop panels, and the 2025 figures are preliminary.

How to read this chart

Each bar is one energy source's share of all the electricity made in the U.S. in a year, so the bars add up to about 100%. The bars start at zero, so a bar twice as long means twice the share. Solar counts only large power plants, not panels on rooftops.

Questions to discuss

  1. Which source makes the most electricity? About how many times more than the smallest bar?
  2. Which of these sources burn fuel and which don't? What share of electricity comes from each group?
  3. Why might a chart of this kind look different in your state than for the whole country?

Source: U.S. Energy Information Administration, Monthly Energy Review (Table 7.2a) · Data as of Dec 31, 2025

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Link for your class: https://chart.ly/charts/where-us-electricity-comes-from

Lesson 6 · Economics

How fast are US prices rising?

Consumer prices in August 2026 were 3.4% higher than in August 2025. Each point compares a month with the same month a year earlier, back to 1914, the first year BLS can compare. Inflation peaked at 23.7% in June 1920 and at 14.8% in March 1980; the 9.1% of June 2022 was the highest since 1981. Prices fell as fast as 15.8% a year in 1921 and 10.7% in 1932. BLS collected no prices in October 2025, during a lapse in federal funding, so that month and October 2026 are missing.

How to read this chart

Each point compares consumer prices in a month with the same month a year earlier. A value of 3 means things cost about 3% more than a year before; below zero means prices fell. The chart shows how fast prices change, not how high they are.

Questions to discuss

  1. Find two times when inflation was highest. What was happening in the country then?
  2. If inflation falls from 8% to 3%, are prices going down, or just rising more slowly?
  3. Find a stretch when the line is below zero. Why might falling prices be bad news for workers and businesses?

Source: U.S. Bureau of Labor Statistics, Consumer Price Index (CPI-U, all items) · Data as of Aug 31, 2026

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Link for your class: https://chart.ly/charts/us-inflation-rate

Lesson 7 · Science

How much rarer is each step up in earthquake magnitude?

In 2025 the world recorded 6,428 earthquakes of magnitude 4.5 to 4.9, 1,983 of magnitude 5, 129 of magnitude 6, 15 of magnitude 7 and 1 of magnitude 8 or more. Each step up in magnitude is roughly ten times rarer, and releases about 32 times more energy. Countless smaller quakes go unrecorded worldwide, so the chart starts at 4.5.

How to read this chart

Each bar counts the earthquakes recorded worldwide in one year within a range of magnitudes. The bars start at zero. Each whole step up in magnitude releases about 32 times more energy, so a magnitude 7 quake is far more than one step stronger than a 6.

Questions to discuss

  1. Roughly how many times more common is each band than the one above it?
  2. The biggest bars are hard to compare with the smallest ones on this scale. What other way could you show these numbers?
  3. The chart starts at magnitude 4.5. Why might smaller earthquakes around the world go uncounted?

Source: U.S. Geological Survey, ANSS Comprehensive Earthquake Catalog (ComCat) · Data as of Dec 31, 2025

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Link for your class: https://chart.ly/charts/earthquakes-by-magnitude

Lesson 8 · Math

How many babies were given your name each year since 1880?

Type any name to see how many U.S. babies were given it each year since 1880, for girls or boys. Emma, shown first, went from 2,003 girls in 1880 down to 414 in 1976, then back up to a peak of 22,719 in 2003; in 2025 it was 12,754. The counts come from Social Security card applications, so the early years undercount everyone. A year with fewer than 5 babies of a name shows as 0, because Social Security leaves those names out for privacy.

How to read this chart

Each point is the number of U.S. babies given a name in one year, from Social Security card applications. Type any name to see its line, for girls or boys. These are counts, not shares, and far more babies are born today than in 1880, so a count can grow just because the country did.

Questions to discuss

  1. Look up your own name or a friend's. When was it most popular, and what might explain that?
  2. Why are counts from the 1880s lower than counts today, even for names that were very popular then?
  3. How could you change these counts to fairly compare a name's popularity in 1900 with today?

Source: U.S. Social Security Administration, Baby Names from Social Security Card Applications (national data) · Data as of Dec 31, 2025

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Link for your class: https://chart.ly/charts/baby-name-popularity

Lesson 9 · Math

What is the typical household income in each state?

In the Census Bureau's 2020–2024 survey, the typical household in the District of Columbia earned $109,870 a year, followed by Massachusetts ($103,960) and Maryland ($103,678). Mississippi was lowest at $56,447, and the U.S. median was $80,734. These are 5-year estimates in 2024 dollars, each with a margin of error.

How to read this chart

Each bar is the median household income in a state: half of households earn more and half earn less. The dashed line is the whole U.S., for comparison. These are survey estimates, and each has a margin of error: the true value is likely within that range, so states with overlapping ranges may not really differ.

Questions to discuss

  1. Find your state. Is it above or below the U.S. median, and by about how much?
  2. Why do statisticians often use the median instead of the average (mean) for income?
  3. Housing and groceries cost more in some states. What would you need to know to compare what these incomes can buy?

Source: U.S. Census Bureau, American Community Survey 5-year estimates · Data as of Dec 31, 2024

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Link for your class: https://chart.ly/charts/median-household-income-by-state

Lesson 10 · Math

Are U.S. roads getting safer per mile driven?

Much safer than in 1980, though not safer than in the early 2010s. In 2024 there were 1.19 deaths for every 100 million miles driven, about a third of the 1980 rate of 3.35. The rate reached a low of 1.08 in 2014, jumped to 1.34 in 2020, when people drove less but deaths rose, and has fallen every year since 2021. Miles driven are the Federal Highway Administration's estimates.

How to read this chart

Each point is the number of people killed in traffic crashes for every 100 million miles Americans drove that year. Dividing by miles driven turns a count into a rate, so years when people drove more or less can be compared fairly.

Questions to discuss

  1. About what fraction of the 1980 rate is the rate in the latest year?
  2. In 2020 people drove less, but the rate went up. What could explain that?
  3. Why is deaths per mile a fairer way to compare years than the total number of deaths?

Source: NHTSA Fatality Analysis Reporting System (FARS) and FHWA Highway Statistics (table VM-2) · Data as of Dec 31, 2024

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Link for your class: https://chart.ly/charts/traffic-deaths-per-mile-driven

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