Popular Science - Page 2

A high-frequency sound test depends on both the listener and the playback equipment. Its result should not be read as an exact hearing age.

Try naming the ink colour without reading the word. When the two disagree, the task becomes noticeably less straightforward.

Two people can find the same colour task very different. Screen settings and viewing conditions also affect what an online colour test can show.

Remembering a short number sequence depends on how it is presented and how you group it. A digit-span test measures one particular task, rather than memory as a whole.

A retirement target becomes easier to discuss when annual spending is written down. The 4% rule is one starting point for a calculation, rather than a promise about future returns.

Replying to a message in the middle of writing seems quick. Getting back to the unfinished argument or line of code can take longer than the reply itself.

Four numbers and a target of 24 leave room for quite different solutions. Fractions, brackets and working backwards make this familiar card game interesting.

Sudoku asks you to place numbers without repeating them in a row, column or box. The challenge is logical elimination rather than calculation.

A profitable trade can still come from a poor decision. Expected value offers a way to discuss the decision separately from its outcome.

A lost duel does not tell you how fast your reflexes are. Reaction time, display delay and network timing need to be considered separately.