A teaspoon of water (about 5 mL) contains 2×1023 water molecules, but each water molecule is comprised of 3 atoms: two hydrogen atoms and one of oxygen. Moreover, if you’d laid down end to end each water molecule from a teaspoon down end to end, you’d end up with a length of 50 billion km — 10 times the width of our solar system.

Everybody knows that there at least three states of matter: solid, liquid, and gas. If you’re a little bit more versed in physics, you also know about the fourth fundamental state of matter called plasma —  a hot ionized gas, with prime examples including lightning or neon signs. But beyond these common states of matter, scientists have discovered a myriad of exotic states of matter that occur under special conditions. One of them is the Bose-Einstein condensate, where atoms chilled to only 0.000001 degrees above absolute zero start behaving like waves, rather than particles as they ought to on the macroscopic scale. Essentially, the atoms behave like one super atom, acting in unison.

Another interesting exotic state of matter is represented by time crystals — regular, boringly ordered crystals with a twist: A fourth dimension, time, is added so that the material exhibits different periodic structures over time. What makes these crystals particularly remarkable has less to do with the fact that they repeat in time but rather more with the fact that they’re intrinsically out of equilibrium. Because time crystals are never able to settle down, say into a diamond or ruby, there’s a lot we can learn from them.

Unlike humans, grasshoppers do not have ears on the side of their head. Like the ears of people, the grasshopper sound detector is a thin membrane called a tympanum, or “eardrum”. In adults, the tympanum is covered and protected by the wings, and allows the grasshopper to hear the songs of its fellow grasshoppers.

The grasshopper tympanum is adapted to vibrate in response to signals that are important to the grasshopper. Male grasshoppers use sounds to call for mates and to claim territory. Females can hear the sound that males make and judge the relative size of the male from the pitch of the call (large males make deeper sounds). Other males can hear the sounds and judge the size of a potential rival. Males use this information to avoid fights with larger male grasshoppers or to chase smaller rivals from their territory.

In order for food to have taste, chemicals from the food must first dissolve in saliva. It’s only once they’ve been dissolved in a liquid that the chemicals can be detected by receptors on taste buds. During this process, some salivary constituents chemically interact with taste substances. For example, salivary buffers (e.g., bicarbonate ions) decrease the concentration of free hydrogen ions (sour taste), and there are some salivary proteins which may bind with bitter taste substances.

Here’s a quick science experiment to test this out — get out a clean towel, and rub your tongue dry; then place some dry foods on your tongue, one by one, such as a cookie, pretzel, or some other dry food. After this session, drink a glass of water and repeat. Did you feel any difference?