Tag: science & technology

Oxalic acid solution effectively dissolves rust (iron oxide) stains from fabric through chemical reaction. The acid converts insoluble iron oxides into soluble iron oxalate complexes that can be washed away. Lime is alkaline and doesn't work, kerosene is an oily solvent ineffective for rust, and alcohol doesn't react with iron oxides.

Convex mirrors are used as rear-view mirrors because they provide a wider field of view by diverging reflected light rays. This allows drivers to see more area behind the vehicle, though objects appear smaller and farther away. Plane mirrors show true size but limited view, concave mirrors magnify but narrow the view, and 'inverted' is not a mirror type.

This statement is approximately correct. Babies are born with about 270-300 bones (some counts vary due to sutures), but many bones fuse together during growth. By adulthood, humans typically have 206 distinct bones as separate bones in the skull, spine, pelvis, and elsewhere fuse together.

The claim is false. While scalp hair does grow relatively fast (about 0.3-0.4 mm per day), other body hair can grow faster. Facial hair in men, particularly beard hair, can grow at similar or faster rates. Additionally, the rate varies by individual, genetics, and hormonal factors.

The claim is false. A fertilized human egg (zygote) remains a single cell for approximately 24 hours before dividing into two cells. The first cell division occurs around day 1, and the embryo develops into a blastocyst by about day 5-6. Spending '1 week as a single cell' is incorrect.

Just like fingerprints, every person has a unique tongue print due to the distinct pattern of papillae (tiny bumps) and fissures on the tongue's surface. This uniqueness makes tongue prints potentially useful for biometric identification.

Epidemiological studies, including research from German institutions, have documented a 'Monday morning phenomenon' showing higher heart attack incidence on Mondays. This is likely due to the stress of returning to work, increased blood pressure in the morning, and behavioral changes (eating, drinking, activity levels) after the weekend.

Prolonged viewing of a computer display causes color adaptation in your eyes. When you then look at a white surface, the fatigued photoreceptors create a complementary color aftereffect, often appearing pinkish. This is similar to the McCollough effect, where color exposure influences subsequent color perception.

Research has found a correlation between higher mole counts and longer telomeres (chromosome end-caps linked to aging). People with more moles tend to have longer telomeres, which is associated with slower cellular aging and potentially longer lifespan. This is based on studies like those from King's College London.