Games

Things to play. Each one teaches the idea in an article, and none of them keeps a score.

Science

Phase Finder
The Moon's phase is where it is in its orbit, not a shape the Moon has.
About 5 minutes
Pole to Pole
A magnet has two opposite ends: unlike poles pull together and like poles push apart.
About 4 minutes

Close the Loop
A bulb lights only when current can leave the battery, go through it and come back: a complete loop, not just a connection.
About 4 minutes
Packet Path
The internet is a net: if one link breaks, the message finds another way.
About 5 minutes

Cloud Ladder
A cloud's name is built from two halves: how high it is gives the first half, and its shape gives the second.
About 4 minutes
Make It Rain
Heat lifts water into the air, cooling turns it back into drops, and it falls again.
About 5 minutes

Fifteen
In a magic square every row, column and diagonal adds to the same number.
About 5 minutes
Narrow It Down
A guess is worth what it destroys, so cutting the middle of what is left beats a bold guess or a lucky one.
About 4 minutes
Shift the Wheel
Every letter of a Caesar cipher moves the same distance, so one number opens the whole message — and the message's own shape can hand you that number.
About 4 minutes
Ten Minus One
Nine times a number is ten times it with one taken from every row, which is what makes the tens digit one less and the digits add up to nine.
About 4 minutes

Mirror Wing
A symmetrical shape is one where every mark has a matching mark across the line.
About 4 minutes

Same Name
A name you can already read in one script unlocks the same symbols everywhere else.
About 6 minutes