the knowledge hub
Byte-sized articles to sharpen your mind
Short pieces that teach one thing properly, for students and for the parents and teachers reading over their shoulder.
- 3 min readsample
Why the sky is blue and sunsets are not
Air scatters short wavelengths far more strongly than long ones, which is why overhead light reaches you blue. At sunset that same light travels through so much more air that the blue is scattered away before it arrives.
Read it - 3 min readsample
What actually happens when bread rises
Yeast is a living fungus that eats sugar and breathes out carbon dioxide, and dough is elastic enough to trap the gas. Everything about a loaf's texture follows from those two facts.
Read it - 2 min readsample
Multiply any two digit number by eleven, in your head
Split the digits, add them, and drop the sum in the middle. It works because multiplying by eleven is the same as multiplying by ten and adding the number again.
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Squaring any number that ends in five
Take the digits before the five, multiply by the next number up, and stick 25 on the end. Twenty five squared is 6 followed by 25, because two times three is six.
Read it - 3 min readsample
Why rereading your notes does not work
Rereading makes material feel familiar, and familiarity is easily mistaken for knowing it. Testing yourself feels worse and works considerably better.
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How to read an exam question properly
Most lost marks are not lost to ignorance, they are lost to answering a slightly different question. The verb in the question tells you what shape the answer has to be.
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