question: Why does our reflection show up in a spoon so clearly right side up on one side and upside down on the other?
comment: One side is concave, while the other is convex. The light from the concave side is directed down from the top and up from the bottom, meaning if you're looking at it from past a certain point, it will appear upside down. The light from the convex side goes up from the top and down from the bottom, so it doesn't do that.
passages: Section::::Chapter 3.
  
  "All in the family: The Genealogy of elements"
   Section::::Chapter 16.
  
  "Chemistry way, way below zero"
   Section::::Chapter 19.
  
  "Above (and beyond) the periodic table"
   Section::::Chapter 18.
  
  "Tools of ridiculous precision"
   Section::::Chapter 1.
  
  "Geography of elements":
   BULLET::::3. Castanets style, two in each hand one spoon held concave-side against the palm held down by the thumb, one between ring and middle fingers with finger tips in the concave side balancing the handle. They can be hit to each other at the convex sides by gripping with the middle and ring fingers.
   BULLET::::2. Salad serving style: one spoon between little, ring, and long finger; the other spoon between ring, thumb, and index finger in such a way that they can be rotated with ring finger as the common axis. They can be hit to each other at the convex sides by gathering the fingers (mostly middle and thumb).
   Section::::Chapter 13.
  
  "Elements as money"
   Section::::Chapter 17.
  
  "The science of bubbles"
   Section::::Chapter 11.
  
  "How elements deceive"
   Section::::Chapter 7.
  
  "Competitive elements: Extending the table, expanding the cold war"
   If a point of an object has coordinates ("x", "y", "z") then the image of this point (as reflected by a mirror in the "y", "z" plane) has coordinates (-"x", "y", "z"). Thus reflection is a reversal of the coordinate axis perpendicular (normal) to the mirror's surface. Although a plane mirror reverses an object only in the direction normal to the mirror surface, there is usually a "perception" of a left-right reversal. Hence, the reversal is called "lateral inversion". The perception of a left-right reversal is probably because the left and right of an object are defined by its perceived top and front, but there is still some debate about the explanation amongst psychologists. The psychology of the perceived left-right reversal is discussed in "Much ado about mirrors" by Professor Michael Corballis (see "external links", below).
   In the sex position, the receiving partner would be in the inner spoon position and the penetrator is in the outer spoon in preparation for rear-entry penetration. For penetration, the partners may separate their upper bodies, with just the pelvises connecting, and their legs can also rest on top of each other. The receiving partner may lift the upper knee to allow for easier penetration.
   The sets of Apostle Spoons, popular as christening presents in Tudor times, the handles of which terminate in heads or busts of the apostles, are a special form to which antiquarian interest attaches. The earlier English spoon-handles terminate in an acorn, plain knob or a diamond; at the end of the 16th century, the baluster and seal ending becomes common, the bowl being fig-shaped. During The Restoration, the handle becomes broad and flat, the bowl is broad and oval and the termination is cut into the shape known as the hind's foot.
   BULLET::::2. The handle of one spoon is held by the ring finger, thumb, and pointing finger, the handle of the other spoon is placed behind the ring finger, but on the inside of the little finger and the long finger in a back to back position with the first spoon. The ring finger works like a hinge and helps to hold both spoons. clasping the fingers lightly causes the spoons to hit each other. This holding style is essentially the same as holding salad spoons for single hand serving; except for this purpose the spoons should not be back to back.
   Section::::Chapter 12.
  
  "Political elements"
   Section::::Chapter 8.
  
  "Bad chemistry" 
  
  Section::::Chapter 9.
  
  "Poisoner's corridor:"Ouch-Ouch""
   Variations on this position include the partners lying on their sides face-to-face or in the scissors position. Anal sex is also possible in this position, along with use of a vibrator.
  
  Section::::Advantages and disadvantages.
   BULLET::::3. The two spoons are held back to back on either side of the right hands index finger, the tips of the spoon handles are held lightly with the little and ring fingers the spoons are then hit down to the leg, up to the inside of the left hand, left thumb and index finger hold lightly and let both handles slip through to get several spoon sounds in one up down movement, spoon tips are allowed to skip over several left hand fingers or folds of the left sleeve to get a repetitive roll. This is the most popular method when sitting.
   In an experimental study (Wiseman and Greening, 2005) two groups of participants were shown a videotape in which a fake psychic placed a bent key on a table. Participants in the first group heard the fake psychic suggest that the key was continuing to bend when it had remained stationary, while those in the second group did not. The results revealed that participants from the first group reported significantly more movement of the key than the second group.
   Section::::Chapter 2.
  
  "The fathers of the periodic table"
  
  In this chapter, the author focuses on the relationships between carbon, silicon, and germanium. He explains how carbon is the backbone of amino acids and the building blocks to everything. He discusses that because of carbon, amino acids all stick together. Then, he describes the carbon element and how it wants to fill its outer energy level with eight electrons so it attaches to four atoms since carbon already has four atoms.
   Section::::Chapter 15.
  
  "An element of madness"
   Section::::History.
   Causing spoons, keys, and other items to appear to bend without any physical force is a common stage magic trick that has many variants. Simply holding a spoon by its neck and rapidly tilting it back and forth can create the illusion that the spoon is bending, due to the way that the human eye perceives the rocking motion.
   If a person stands side-on to a mirror, left and right will be reversed "directly" by the mirror, because the person's left-right axis is then normal to the mirror plane. However, it's important to understand that there are "always" only two enantiomorphs, the object and its image.Therefore, no matter how the object is oriented towards the mirror, all the resulting images are fundamentally identical (as Professor Corballis explains in his paper "Much ado about mirrors", mentioned above).
  