Streak · 7 days+185 XP
7-Day How-It-Works Streak
Each day, look up how one engine or motor works (car, jet, steam, electric) and note one fact. Check in once a day.
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Science · Facts & stats · iChallenge network
The Engine Challenge
Daily facts and stats about engines, plus real challenges to put them to work.
Warm-up questionNot ranked · tap an answer
Which unit is traditionally used to describe an engine's power?
Horsepower was popularized in the 1700s to compare the output of steam engines with the work of horses.
Level1Rookie
XPPlay a round to earn XP
Streak0days
LeagueBronzeweekly
Daily #2Resets 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
Draw the Four Strokes
Sketch the four strokes of a piston engine with labels and post a photo link or a short write-up.
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Streak · 10 days+200 XP
10-Day Machine Spotter
Spot one engine- or motor-driven machine each day and note what energy source it uses. Check in daily.
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By the numbers
Live counts from ChallengeEngine.com. All arena stats →
Facts in the pack12
Visitors, 30 days40
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Questions
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100 points per correct answer, up to 50 more for speed, a combo multiplier for answers in a row, and a bonus for a perfect round.
When do new questions drop?
Fresh rounds rotate continuously from the topic bank.
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Everyone on this arena gets the same five questions each day, from easy to hard. You get one ranked attempt; practice rounds are unlimited.
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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.