Why does tea change colour when you add lemon? How fat do you have to be to become bulletproof? What would be the effect on the Earth, if an alien spaceship came and dragged the moon away?

In 1994, the New Scientist magazine began publishing a weekly column called ‘The Last Word’ with questions and answers on everyday science; some weird, some witty, others downright wacky. More than a decade later, the column still continues and now, The Sunday Times launches ‘YoY’ in similar vein.

Readers are requested to send in their questions, and answers to the questions that we will publish weekly. As the New Scientist put it, The Last Word is devoted to the small questions in life.

Please send in your questions and answers to ‘YoY’, C/o the Sunday Times, P. O. Box 1136, Colombo or email features@sundaytimes.wnl.lk. Remember the success of this column depends on you… This is your space.

Below are some answers to some of our own questions that appeared two weeks ago.

• Why does hair sprout out of our ears and nose as we age, when at the same time it’s falling off the top of your head?
  A. Male-pattern baldness (also known as Androgenetic Alopecia) is the most common form of hair loss for men, representing up to 90% of all male cases. Mild to moderate hair loss affects about 50% of all men by the time they are 50. Male pattern hair loss results in either a receding hair line or thinning at the crown of the head. It occurs due to a chemical known as dihydrotestosterone (or “DHT”) which builds up around the follicle and eventually kills the follicle and the hair.
  A follicle’s resistance to DHT is genetic – which is why some people go bald and others do not.
  Aging makes baldness more likely. Sixty five% of men have noticeable hair loss by age 60.
  Millions of men worldwide suddenly get odd strands of hair protruding from the shadows of their noses and ears by the time they hit 30 and the chances of them emerging and multiplying only increase as you get older.
  (Before you do away with unwanted hair, understand that the unsightly hair's main purpose is to prevent dirt from entering your nose and ears -- it acts as a barrier, the same way lashes protect your eyes and your hair shelters your head from the cold. It's also important to note that your ear and nose hair has likely always been there -- it has only grown with time as a result of hormonal changes in your body.)
  Some hair experts link this growth to the male hormone DHT (dihydrotestosterone), although the exact relationship of DHT to nose and ear hair growth is still unclear.

• Do plants feel pain?
  A. Supporters of the theory that plants feel pain cite an experiment that one farmer used a device to “scientifically” catch the sounds of plants “crying out” and “screaming” in pain. They state that as humans our limited range of hearing cannot pick up the “screams” of plants but that machines can.
  The truth is that plants, when stressed, release a chemical called ethylene.
  This chemical indicates that the plant needs to take measures against the perceived stressor. Scientists measured levels of ethylene released from stressed plants by “listening” to them using lasers until a certain frequency was measured.
  While this research shows that plants might have a stress-avoidance response, some say that it is, quite a stretch to refer to this as “pain”. It is even more erroneous to equate this response with the pain suffered by animals and human beings. Plants lack nerve endings, brains, hormones, and other structures that would allow them to experience pain. They also lack the ability to move away from sources of stress, an evolutionary trait linked with the ability to feel pain.

Answers are welcome for the following questions:

• Why do owls hoot with monotonous regularity for long periods of time Surely it can't be to attract mice or a mate? (It must be the ultimate turn-off)
• Why do bats get impaled on telephone wires, when every other flying creature seems to avoid doing so?