Posted in Science & Nature


The most potent and frequently used household cleaning product is bleach. Bleach is a diluted solution of sodium hypochlorite (NaClO), which has powerful antimicrobial properties thanks to the element chlorine. This is also the reason chlorine is used to treat tap water and disinfect pools.

Although it is an extremely useful chemical, chlorine also has a very dark side. Chlorine gas is a highly toxic gas, which forms hydrochloric acid when breathed in and seriously burns the respiratory tract. Due to its toxicity, chlorine gas was used as a weapon of mass destruction in World War I. However, this terrifying gas can be made very simply at home. Unfortunately, this is often done accidentally (but sometimes on purpose) and causes significant damage.

The key warning for using bleach is that it must never be mixed with other cleaning products. If mixed with an acid cleaner, it causes a chemical reaction that produces chlorine gas, while mixing it with ammonia creates chloramine, another deadly gas (although dangerous in itself, chloramine can sublimate into chlorine gas too). Therefore, many people suffer a loss of smell, consciousness or their lives by accidentally mixing two cleaning products or cleaning up urine with bleach. A major problem is that these victims tend to be children who unknowingly mix the chemicals, creating a horrible accident. What is more unfortunate is that some people choose to end their lives using this method.
If you do find a person rendered unconscious by chlorine, it is imperative to quickly move them to a well-ventilated area, while not endangering yourself. An ambulance should be called right away.

As seen from above, simple chemicals found easily at home can produce toxic gases, which can cause irreversible damage. Thus, one must never mix bleach and cleaning products and should educate their children on the dangers of chlorine gas.

Posted in Science & Nature

Taste Of Water

It is a common chemical fact that water is flavourless and odourless. However, most people will know that water “tastes” subtly different each time.
Taste is composed of information from taste buds on the tongue, combined with the sense of smell from your nose. Although water itself has no flavour or smell, it has many things dissolved in it such as gases and minerals that can be tasted.
This is why tap water can taste bad due to the chlorine used to treat it, or metals such as copper that have come off the pipes. 

It is also well known that temperature affects the taste of water. The ideal temperature is between 10~17°C, where oxygen saturation is sufficient, giving the water a “refreshing” taste. Any hotter and the oxygen escapes, giving the water a flat taste, just like distilled water. Warm water also causes the brain to think it is saliva or mucus, sometimes producing an uncomfortable sensation. Any colder, the tongue is numbed and it loses its ability to taste.

When making tea, the ideal temperature is 70~80°C. A simple way to achieve this is by leaving a cup of boiled water for a minute or two before putting the teabag in. This is the temperature when the dissolving of the various chemicals in tea leaves is optimal. If it is too hot, bitter-tasting tannins and catechins are released in excess, whereas if it is too cool, not enough dissolving occurs.