Vocabulary — Click a Card to Flip
Each card opens for 8 seconds, then closes. Cards never lock — you can re-open any card as many times as you need. Only one card opens at a time.
Matching Practice
Click a term on the left, then click its definition on the right. Correct matches lock in green. Each correct match = 1 point.
Terms
Definitions
Reading: Light Is the Messenger
Fingerprints in Starlight
Stars are unimaginably far away. The closest star to Earth, other than the Sun, is about 40 trillion kilometers from us. No spaceship will ever travel there in a human lifetime. So how do astronomers know what stars are made of?
The answer is hidden in the light itself. In the early 1800s, a German scientist named Joseph von Fraunhofer pointed his telescope at the Sun and split its light through a glass prism. To his surprise, the rainbow he produced was not smooth. It was crossed by hundreds of dark lines at very specific positions. Those lines turned out to be the chemical signature of the Sun.
Each element on the periodic table absorbs and emits light at its own unique set of wavelengths. When hydrogen gas is heated, it glows with a specific pattern of colored lines. Helium glows with a different pattern. Oxygen, nitrogen, carbon, and silicon each have their own unmistakable fingerprint. No two elements share the exact same set of lines, just as no two people share the exact same fingerprints.
Astronomers point telescopes at distant stars, capture the starlight, and split it into a rainbow called a spectrum. By matching the bright lines in the star's spectrum to known patterns from elements on Earth, they can identify what the star is made of. This is how we know the Sun is mostly hydrogen and helium. This is how we found helium in the Sun before it was ever found on Earth. This is how we know the universe is made of the same atoms as your hand.
Wavelengths of visible light are measured in nanometers (nm). One nanometer is one billionth of a meter. The visible spectrum runs from about 400 nm (violet) to 700 nm (red). The Earth Science Reference Table on page 19 shows the emission spectra of six common elements found in stars: hydrogen, helium, carbon, nitrogen, oxygen, and silicon. Learning to read this chart is one of the most powerful skills in astronomy.
The Reference Table You Will Use
This is the chart from page 19 of the New York State Earth and Space Science Reference Tables. Take a moment to look at it. Notice how each element has its own pattern of lines.
Reading Response
Show what you understood from the reading. Each item below is worth 1 point.
Tutorial: How to Read the Emission Spectra Chart
Walk through these steps with the actual reference table. The chart appears on every page from here on so you never have to flip back.
1What the Numbers on the Top Mean
The numbers across the top and bottom of the chart go from 400 to 700. These are wavelengths measured in nanometers (nm). A nanometer is one-billionth of a meter — smaller than a virus.
Wavelengths from 400–700 nm are exactly the range of light your eye can see. Below 400 is ultraviolet (invisible). Above 700 is infrared (invisible).
Color order on the chart, left to right: violet (400) → blue (450) → green (500) → yellow (570) → orange (600) → red (700).
2What the Vertical Lines Mean
Each row of the chart is one element: Hydrogen, Helium, Carbon, Nitrogen, Oxygen, and Silicon. The thin black vertical lines inside each row show the exact wavelengths where that element gives off light.
An element only emits light at its own specific wavelengths. The blank white space between lines shows wavelengths where the element does not emit. This is what makes each pattern a fingerprint.
3How to Find a Specific Wavelength
To find the wavelength of any line: look up at the wavelength scale and read straight down to the line. To find which element gives a certain wavelength: pick a number on the scale, draw an imaginary vertical line down through every element, and see which rows have a line at that exact spot.
This is the skill the next page will help you practice.
The Chart (Always Visible from Here On)
Wavelength Investigator
Slide the red marker across the wavelength scale. Whenever the red line crosses a black line on any element row, that element is emitting light at that exact wavelength. This is exactly what astronomers do when they look at starlight.
The colored band at the top of the chart tells you what color that wavelength corresponds to. The lines below show which elements emit at that wavelength.
Quick Checks (1 point each)
Mystery Star Simulation
You are an astronomer. A telescope just captured the spectrum of an unknown star. By comparing the lines in the star's spectrum to your reference table, decide which element produced that pattern. Each correct identification = 1 point.
Part 1: Identify the Element
Read the spectral lines below. Use the reference chart to identify which element each pattern belongs to. Completing this whole table is worth 4 points.
| Mystery Spectrum | Your Identification |
|---|
Part 2: Draw the Spectral Lines
Click on the wavelength scale to add a black spectral line at that location. You are drawing the emission pattern for Hydrogen. Use the reference chart above to know where the lines should go. Click an existing line to remove it.
Practice Questions
10 basic questions on reading the chart. Each question is worth 1 point. The reference table is right here so you do not have to flip back.
Regents-Style Questions
10 questions written in NYS Regents format. Each is worth 1 point.