What is the hardest mineral on the Mohs scale?
AnswerDiamond
Diamond ranks 10, the top of the Mohs scale.
Science · Facts & stats
Soft facts & stats
7 fact-checked facts about softness and hardness of materials, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
Down feathers used in soft pillows and jackets come mainly from which birds?
AnswerDucks and geese
Down is the fluffy under-plumage of ducks and geese, which traps air for warmth.
Going deeper
On a pencil, what does a 'B' grade mean compared with an 'H' grade?
AnswerSofter, darker lead
B pencils have more graphite and write darker and softer; H pencils are harder and lighter.
What is a soft-shell crab?
AnswerA crab that has recently molted its old shell
Crabs shed their shells to grow, and for a short time the new shell is soft.
Which of these metals is soft enough to be cut with a knife?
AnswerSodium
Alkali metals like sodium are so soft they can be sliced, while tungsten is one of the hardest metals.
Expert level
In woodworking, 'softwood' comes from which kind of trees?
AnswerConifers such as pine and spruce
Softwood and hardwood are botanical terms: softwoods come from conifers, hardwoods from flowering trees.
Balsa, one of the lightest and softest woods, is classified as what?
AnswerA hardwood
Balsa comes from a flowering tree, so it counts as a hardwood despite being very soft.
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