Bondle
The daily science puzzle. Name something in each category, and the rarer your answer, the stronger your bond.
Past puzzles
Missed a day? Play it now. Past puzzles don’t change your streak.
Practice
Unlimited random rounds, any time. Nothing is scored.
How Bondle works
Six rounds a day
Every day brings six categories, one each from physics, chemistry, biology, earth science, space and general science. For example, “Name a force”, “Name a noble gas” or “Name a moon in our Solar System”.
Rare beats obvious
Any correct answer scores, but the obvious ones score least. You have 30 seconds and two tries per round, so go for something rare, or play it safe.
Your bond strength
Your total is in kJ/mol, compared with real bond energies. Beat a C–C bond (348 kJ/mol)? A perfect day is 600, almost a C=C double bond.
Answer tiers
Questions
Do I need an account?
No. Bondle is free and works in any browser. Your streak and stats are kept on your device. If you also use the Bondline notebook in the same browser, your Bondle stats show up there too.
When does a new puzzle come out?
At midnight, your local time. Everyone gets the same six categories on the same date.
My answer was right but didn’t count!
Each category has a long list of accepted answers. Short forms count too: symbols and formulas (CO2, Hz), initials (ISS, LED), a surname, part of a name (“Fuji” for Mount Fuji), plurals, British or American spelling, and extra words such as “the planet Mars”. Small typos are forgiven. If we still missed a correct answer, use “Suggest an answer we missed” on the results screen and we’ll add it.
Why doesn’t “ethene” count as a typo of “ethane”?
In science, one letter can make a different thing. Typos and short forms are accepted only when what you typed isn’t itself another real answer.
Where did the organic chemistry rounds go?
The daily puzzle is now general science. The specialist chemistry categories are still there: choose “Chemistry only” under Practice.
What is Bondline?
Bondline is a free organic chemistry notebook: notes, curly-arrow mechanisms, 3D molecules, and practice for naming, stereochemistry and spectra. Bondle is its daily puzzle.