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 2 · Space
How do astronomers find planets around other stars?
The interactive chart needs JavaScript. The numbers are on the chart's page.
As of November 2026, 4,785 of the 6,451 confirmed exoplanets, about 74%, were found by the transit method: a telescope sees a star dim slightly as a planet passes in front of it. Radial velocity, which spots a star's slight wobble as a planet tugs on it, found 1,204. Only 98 have been photographed directly (imaging).
Questions to discuss
- In one sentence of your own, what does this chart show?
- Find the biggest change or difference in the chart. What might explain it?
- Who collected these numbers, and how recent are they? What else would you want to know before drawing a conclusion?
Source: NASA Exoplanet Archive, Planetary Systems Composite Data (Public domain (NASA data); this research has made use of the NASA Exoplanet Archive, operated by Caltech under contract with NASA) · Data as of Nov 4, 2026
Open the chart and its numbersChart 2 of 2 · World
How much does each country spend on health care per person?
The interactive chart needs JavaScript. The numbers are on the chart's page.
In 2023, the United States spent $13,473 per person on health care, about 10 times the world figure of $1,317. Germany spent $6,395, Japan $3,638, China $763 and India $85; Madagascar spent the least, $17. Search 191 countries and territories. Spending counts what governments, insurers and households paid for health care, but not new hospitals or equipment, in US dollars at each year's exchange rates, not adjusted for differences in prices.
How to read this chart
Each bar is what a country spent on health care in a year, by governments, insurers and households together, divided by its population and turned into U.S. dollars. The dashed line is the world. The figures aren't adjusted for prices, so a dollar buys more care in some countries than others.
Questions to discuss
- About how many times the world figure does the United States spend per person?
- Does spending more on health care per person always mean people live longer? What other chart on Chartly could help you check?
- Doctors and nurses are paid less in some countries. How would that change what these dollar figures can tell you?
Source: World Bank, World Development Indicators: Current health expenditure per capita (current US$) (CC BY 4.0 (credit the World Bank)) · Data as of Dec 31, 2023
Open the chart and its numbersTeachers: make your own chart assignment, or change this one. Free, no account needed.