Chemistry
The periodic table, formulas and reactions. Nothing is saved, and no account is needed — for the table, not even a sign-in.
The periodic table
Tap any element to see what it is and where you have already met it.
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Practise
Year
showing every year
A suggestion, not a limit — pick any year, or show everything. Your choice is kept on this device so you do not have to set it again.
Topic
Tap one to see what it is and start.
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A table you can read, not memorise
Tap any element and it tells you where you have already met it: sodium is table salt, tungsten is the wire in an old bulb, helium is why your voice goes squeaky. A periodic table is 118 boxes of nothing until somebody says that.
The columns are the point
Elements in the same column behave alike, because they have the same number of outer electrons. Laid out properly you can see that without being told — which is what the shape of the table is for.
Every topic says what it actually is
An atom is a wasp in a cathedral: a tiny heavy centre and a great deal of nothing. A balanced equation is scales you are not allowed to unload. The picture comes first, then the rule.
Keep the scores, and see what is not landing.
Above, nothing is kept. With an account you set a topic for a child, and afterwards see the score, which questions keep going wrong, and whether it is getting better. Children never sign in — they are profiles under your account, with no email address and no password.