7 The expiration date on water bottles is not for the water but for the plastic bottle it is packed in.

While water does not go bad with time, the packaging does come with an expiration date. Our water bottles are made of polyethylene terephthalate (PET). PET is safe for packaging, but it definitely expires with time. If you consume water after the expiration date that is mentioned on the bottle, you may find the taste or smell to be unpleasant. That is because toxins from the bottle start leaching into the water.

The reason why there is an expiration date in the first place is because of a 1987 New Jersey law that required every food product to display an expiration date of two years. However, the U.S. Food and Drug Administration did not have any such limitation on the shelf life of bottled water. New Jersey has since changed its law, but displaying the expiration date on the water bottle still continues to be an industry norm. (source)

8 There is a lake in Australia that is pink in color. The pink hue of Lake Hillier is due to high salinity and a species of algae living in the water.

Lake Hillier is a 250-meter-wide lake located in the Goldfields-Esperance in Western Australia. The pink lake is a famous attraction for many tourists and researchers from around the world. After analyzing samples of the lake water, researchers have found that the main reason for the strange pink color is algae known as Dunaliella salina. D. salina produces pigment compounds called carotenoids which help it to absorb sunlight giving the algae a reddish-pink color. Scientists also found out a type of bacteria called Salinibacter ruber which is red in color also contributes to the pinkish hue of Lake Hillier. (source)

9 Almonds are a part of the peach family.

This one might come as a surprise to many as almonds are widely classified as nuts. But almonds, in fact, are a part of the Prunus family which includes apple, peach, cherry, plum, apricot, and nectarines. Almonds originated in Central Asia and China and have since been grown in various parts of the world. Almonds are found in the kernel of the almond fruit. Most of the fruits from the Prunus family have poisonous seeds containing cyanide, unlike almonds which are safe and edible.

The evolution of almond seeds is quite strange. Fruits like apples or peaches have poisonous seeds as they have evolved to keep the animals from eating them thus allowing the seeds to sprout. In the case of almonds, we are familiar with the wild almond which is indeed poisonous. But the “sweet” almonds we eat evolved differently and were protected and cultivated by the early farmers. (source)

10 Snails’ teeth are the strongest biological material on Earth. They can withstand pressure high enough to turn carbon into diamond.

Scientists from the University of Portsmouth in the UK discovered that snails’ teeth are made out of the strongest natural material on Earth. These microscopic teeth are located on their tongue and are called “radula.” The study was done on a species of limpets known as Patella vulgata. The results of the study showed that their teeth were, in fact, stronger than spiders silk and Kevlar. Until the discovery, spider’s silk was considered to be the strongest natural material. The difference in strength between the two is about five times.

The teeth are formed from a mixture of goethite nanofibres and chitin. The length of every tooth is about 1 mm, and they are a hundred times thinner than a human hair. (source)

11 A “gentleman’s notch” is the notch in the heels of men’s dress shoes. The reason for the slight cut is to prevent your heel from getting caught on your pant’s cuffs.

The practice of making a cut on the corner of the shoe’s heel began from the Victorian Era. Men would simply bend to tie their shoelaces which would make creases all over their trousers, so they decided to put on the shoes first and then put on their trousers. This again would damage or tear the pants if the sharp corner of the heel got caught in the cuffs. So eventually, they came up with an idea to make a small cut on the heel of the shoe to solve the problem. As these cuts were only found on the shoes of well-groomed gentlemen, it was named as a “gentleman’s notch.” (source)

12 Our tooth enamel is made out of one of the strongest natural materials on Earth which makes it stronger than steel and iron. The tooth enamel is very durable and can survive for thousands of years.

Tooth enamel is composed of hydroxyapatite which is crystalline calcium phosphate. On the Mohs scale which is a scale used to determine the hardness of the mineral, tooth enamel is rated 5 on the scale of 10. Comparatively, iron and steel are rated below tooth enamel with a 4 and 4.5 rating respectively. Tooth enamel (apatite) is so strong that it can sustain heat up to 1,600 degrees Fahrenheit. In one of the studies conducted, it was found that the enamel of the human wisdom tooth is as strong as sharks’ teeth. (1, 2)