Streak · 7 days+185 XP
7-Day Walk-or-Bike Trip Streak
Swap one short car trip a day for walking or cycling, or plan a car-free errand. Check in daily.
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Science · Facts & stats · iChallenge network
The Carbon Challenge
Daily facts and stats about carbon, plus real challenges to put them to work.
Today's 3 challenges
Graphene is a sheet of carbon how thick?
You went
Level1Rookie
XPPlay a round to earn XP
Streak0days
LeagueBronzeweekly
Daily #32Resets at midnight UTC
Today's round
- 5 questions
- 20s each
- 0 played today
One ranked attempt per day. Practice as much as you like.
Challenges
Join one, log your days or post your proof. Finishing earns XP and the Finisher badge.
Proof+250 XP
Standby Power Hunt
Find at least three devices at home left on standby, switch them off at the plug and post a short write-up of what you found.
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Streak · 14 days+220 XP
14-Day Lights-Off Streak
Switch off lights in every empty room each day for two weeks. Check in once a day.
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By the numbers
Live counts from CarbonChallenges.com. All arena stats →
Facts in the pack12
Visitors, 30 days29
Leaderboard
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Badges
Earned on any arena, shown on your profile everywhere.
First RoundFinish your first daily round.
FlawlessAnswer every question in a round correctly.
LightningA perfect round in under 25 seconds.
On a RollPlay 3 days in a row.
Week WarriorPlay 7 days in a row.
UnbreakablePlay 30 days in a row.
ExplorerPlay daily rounds in 5 different arenas.
GlobetrotterPlay daily rounds in 25 different arenas.
PolymathPlay daily rounds in 5 different topics.
In the ArenaJoin your first challenge.
FinisherComplete a challenge.
RecruiterInvite a friend who finishes a round.
CaptainInvite 5 friends who finish a round.
PodiumFinish a day in an arena's top 3.
ChallengerReach level 10.
Profile SavedSave your progress with an email.
Save your progress
Add your email to keep your level, streak and badges if you switch devices, and carry them to every iChallenge arena. One email when you save; no spam.
Put a prize on a challenge
Fund a prize on CarbonChallenges.com and your brand sits on the challenge card, the leaderboard and every finisher's share. Prizes only appear once they're funded, so players can trust what they see.
- Pick the challenge and the prize
- We review entries before a funded prize is awarded
- You get finisher and engagement numbers after it closes
Current sponsors
Questions
Do actions get verified?
Post a link or note as proof. Approved entries finish the challenge and earn the Finisher badge.
Does the network donate?
Sponsors can fund cleanup and conservation prizes. Each funded prize is listed on its challenge card.
How does the daily round work?
Everyone on this arena gets the same five questions each day, from easy to hard. You get one ranked attempt; practice rounds are unlimited.
How is my score calculated?
100 points per correct answer, up to 50 more for answering quickly, a combo multiplier for answers in a row, and 150 bonus points for a perfect round.
Is it free?
Yes. Playing, streaks, badges and leaderboards are free. Some challenges carry a sponsor-funded prize; the challenge card shows it when one is funded.