Wordle for science · one puzzle a day · no account

Like Wordle, for science and math.

Six guesses to find the hidden element, planet, animal, or number. Every guess shows how its real properties compare with the answer, so you learn the periodic table, the solar system, the animal kingdom, and the numbers 1 to 100 by playing.

Works on phones, tablets, and Chromebooks. Nothing to install.

Elements · #12solved in 3
Element
Atomic #
Period
Group
Category
State
Iron (Fe)
26▲
4
8▲
Tran­si­tion metal
Solid
Zinc (Zn)
30▼
4
12▼
Tran­si­tion metal
Solid
Copper (Cu)
29
4
11
Tran­si­tion metal
Solid

Iron was close on atomic number and the answer was higher. Zinc was one group too far. Copper, atomic number 29, in three.

If you can play Wordle, you already know the rules.

Same daily rhythm, same six guesses, same shareable grid. The difference is what the colors mean.

Pick a category

Elements, Solar System, Animals, or Numbers. Each has its own daily puzzle, and everyone gets the same one.

Make a guess

Type any element, body, animal, or number. The board compares five of its real properties with the hidden answer.

Read the clues

Green is an exact match. Yellow is close. Arrows say whether the answer is higher or lower. Six guesses, then the reveal and a fact worth remembering.

Four categories, real figures.

No trivia-night gotchas. Every clue is a measurable property, in the units scientists actually use.

Elements

Atomic number · Period · Group · Category · State at room temperature

After a week you stop seeing the periodic table as a list and start seeing it as a map. Noble gases on the right, alkali metals on the left, and a feel for where everything else sits.

44 elements

Solar System

Type · Distance from the Sun (AU) · Diameter (km) · Moons · Rings

Planets, dwarf planets, and the big moons. You will learn that Ganymede is larger than Mercury, and that Saturn has more moons than every other body combined.

23 bodies

Animals

Class · Diet · Legs · Mass (kg) · Lifespan (years)

From a honey bee to a blue whale, nine orders of magnitude of mass. A quiet lesson in classification and scale, and the reason a tortoise outlives a tiger.

37 animals

Numbers

Value · Parity · Prime or composite · Digit sum · Number of divisors

Number sense without a worksheet. Players start noticing that primes have exactly two divisors and that squares always have an odd number of them.

1 to 100

One game for every OpenSciEd unit.

Eureka Unit Review turns each middle school unit into its own daily puzzle. Guess the rock, the substance, the body part, the sound. Six guesses, real figures, a fact at the end.

Grade 6

6.1 Light & Matter · 6.2 Thermal Energy · 6.3 Weather, Climate & Water Cycling · 6.4 Plate Tectonics & Rock Cycling · 6.5 Natural Hazards · 6.6 Cells & Systems

Objects and light, materials and heat, world climates, rocks, hazards and warning times, cells to systems.

Grade 7

7.1 Chemical Reactions & Matter · 7.2 Chemical Reactions & Energy · 7.3 Metabolic Reactions · 7.4 Matter Cycling & Photosynthesis · 7.5 Ecosystem Dynamics · 7.6 Earth’s Resources

Bath-bomb substances, energy in reactions, the digestive system, producers and decomposers, the Borneo rainforest, resources.

Grade 8

8.1 Contact Forces · 8.2 Sound Waves · 8.3 Forces at a Distance · 8.4 Earth in Space · 8.5 Genetics · 8.6 Natural Selection & Common Ancestry

Sports balls in collisions, sounds by frequency and loudness, magnets, the solar system, chromosomes and genes, living and fossil organisms.

Built for a bell ringer

Same puzzle for the whole class · unlimited practice · works on any device

Each unit has its own link, so you can post exactly the unit you are teaching. Nothing to install and no student accounts.

18 units

A three-minute bell ringer that students ask for.

Put today’s puzzle on the board. The class argues about the next guess. You get a warm-up that reviews real content and ends with a fact to discuss.

  • Nothing to install, no logins. Runs in any browser on phones and Chromebooks.
  • Maps to what you teach. Periodic trends, the solar system, classification and scale, number properties.
  • Never blocked. Practice mode means a lesson never waits for tomorrow’s puzzle.
  • Figures you can stand behind. Rounded, sourced from standard references, and labeled with units.

Questions

Is Eureka free?
Yes. Play every category every day at no cost.
Do I need an account?
No. Your stats and streaks are saved in your browser on the device you play on.
When does the puzzle reset?
At midnight in your local time zone. Each category gets its own new puzzle.
Is this made by Wordle or The New York Times?
No. Eureka is an independent game inspired by the daily-puzzle format. Wordle is a trademark of The New York Times Company, which is not involved with Eureka.
How accurate is the data?
Figures are rounded to the precision useful for a puzzle and taken from standard references. Moon counts are confirmed moons as of 2025, and animal masses and lifespans are typical adult values. If you spot an error, tell us and we will fix it.

Today’s four puzzles are waiting.