For example -- I am typing this post on a laptop computer that is powered by a lithium battery. No one has the slightest idea how and why it works.
Metallic lithium can intercalate between the graphene sheets in graphite in the anode. This anode is in contact with the electrolyte containing lithium salt. It needs to be an unreactive solvent that remains liquid over a wide temperature range, which narrows the choice tremendously. Initially, propylene carbonate was the electrolyte; that was a serious problem. The electrolyte diffused between the graphene sheets and weakened the anode. Li batteries were inefficient and dangerous.
In the early 1990s, it was discovered that, counterintuitively, using ethylene carbonate, which is a smaller molecule, solves this problem; only then Li batteries became commercialized. Electrochemical reduction of the solvent produces dense material that passes lithium cations through, but blocks solvent molecules. No such material is formed for propylene carbonate. Li battery can be cycled many times due to this solid electrolyte interface formation; without it, the battery cannot work.
That was 20 years ago. Still no one knows what chemical process yields this material, what is this material, and why a small structural change in the electrolyte makes such a colossal difference in the performance. There have been many theories, but even the first steps towards the formation of this material remain unknown. Higher voltage operation requires different electrolyte, while it is not known how the present one is working. Millions of dollars have been invested into solving of this problem. So far it provided nearly zero insight.
It is not billions of light years away. It is not in the distant past. It is not a speculative field requiring the highest degree of abstraction. It is not petascale computing providing pornographic thrills of universal catastrophe.
In the imagination of the masses, the unknown begins far away in the abode of the exotica and speculation. This impression is nurtured. Bookstores carry hundreds of popular science books on string theory, cosmology, climate change, evolution, and the wonderful human brain. Other topics are banished to a minute fraction of such books. “Science literacy” tests quiz the initiated on their command of abstract dogmas acquired through no exercise of one’s ability to generate knowledge. G-d forbid to quiz them on how a vacuum cleaner works.
My laptop is the microcosm reflecting the macrocosm. Nearly everything about the operation of “smart” semiconductor chips, LCD screens, and other computer components is, in fact, well understood. By contrast, the “dumb” battery remains an enigma.
Only a scientist would know that.