Materials & Engineering questions
21 fact-checked questions — tap any to predict the answer, then read why.
- Why can dark silk feel elegant and cool indoors but become hot fast in direct summer sun?
- Why can a product sold as "ice silk" feel cool even if it contains no silkworm silk?
- When a damp fabric cools your skin in moving air, what is doing the most useful cooling work?
- What does silk's moisture regain explain if the fabric can absorb water vapor yet still feel dry against skin?
- Why can smooth silk satin feel cooler on skin than a fuzzy silk fabric made from the same fiber?
- Why can a thin silk sheet feel cool at first touch but still fail to keep you cool all night under a warm blanket?
- Why does the cool feeling of silk fade after your skin rests on the same spot for a while?
- Why can a silk pillowcase feel cool the first moment your cheek touches it even when the pillowcase is already at room temperature?
- Why do denim mills use several short indigo dips instead of one long soak?
- Why is the inside of many blue jeans much paler than the front?
- Freshly indigo-dyed jeans yarn can look yellow before blue. What flips it?
- Why is titanium used in implants?
- Why is plastic used for bottles?
- Why do bridges use steel cables?
- Why is graphite soft but diamond hard?
- Why is aluminum used for planes?
- Why are metals good conductors?
- Why does concrete need time to cure?
- Why is glass transparent?
- Why does rubber stretch and return?
- Why is steel stronger than iron?