The mirrors in kaleidoscopes are the primary optical system. Kaleidoscopes typically have more than two mirrors. The objective is to reflect the items inside the tube into a variety of shapes.

Quokkas love to approach the humans who visit Rottnest with their cheeky grins. As well as giving them the cute factor, a quokka's smile helps them cool down. 

The Sun appears to have existed in perpetuity, unchanged, but this is not the case. The Sun is gradually heating up. Every billion years, it becomes 10% more luminous. In fact, within a billion years, the Sun's heat will be so intense that liquid water will no longer exist on Earth's surface. Life on Earth as we know it will cease to exist. Bacteria may still exist underground, but the planet's surface will be scorched and uninhabitable. It will take another 7 billion years for the Sun to reach its red giant phase, at which point it will engulf the Earth and destroy it entirely.

This lowers your risk of developing acne but also makes it easier for your skin to become dry. Insufficient skin hydration is one of the main causes of fine wrinkles, but fortunately, it's simple to address with a decent moisturizer.

Who knew there was so much to know about kites? Aerial warfare has played an important role in history, particularly during both World Wars. Kites were the first air devices used to drop bombs on enemies before planes were invented, let alone used for war. They were also used to communicate and distribute messages through leaflets. Later in the nineteenth century, kites would be used to lift up a soldier for surveillance of their enemies and intelligence gathering.

The brain's structural changes as a result of Alzheimer's disease. As a result of the cerebral cortex and other brain regions shrinking as a result of Alzheimer's disease, the ventricles in the brain can grow. These alterations can make it difficult to detect movement, focus on an object, and change how the pupils respond to light.

The World's Most Famous Treasury Is Actually A Graveyard Petra's Treasury, contrary to popular belief, is not a looming maze of booby-trapped rooms designed to separate the righteous from the unworthy, but rather a relatively small area that is most likely a beautifully decorated graveyard. Any buried treasure was most likely removed a long time ago, but the Treasury facade is a work of art, lovingly carved by the Nabataeans centuries ago.

During the Battle of Long Island on August 27, 1776, George Washington and his troops were fighting a losing battle against the British. Recognizing that they were being surrounded necessitated a chance to flee. A thick fog descended on the area, giving Washington the time and cover he needed to withdraw 9,000 of his troops into Manhattan. When the fog lifted, the British descended on the American positions, only to find them deserted. The Americans' miraculous retreat saved their lives during a pivotal early battle in the American War of Independence.

Another obscure Mexican truth. The country is well-known for its Corona and Sol beers, which are popular around the world, but did you know there are MANY other types of cool Mexican beer? Pacifico, Indio, Tecate, Victoria, and Bohemia are just a few examples.

Herophilus, an ancient Greek surgeon, was the first to formally refer to the pancreas as a gland in about 300 BCE. The name "pankreas," which means "all flesh," was given to the organ about 400 years later by another Greek anatomist and surgeon by the name of Ruphos. This may have been due to the absence of bone or cartilage in the organ. (Pancreata or pancreases, by the way, are the plural forms of the word pancreas.) Later, in the 16th century, the term "sweetbreads" was used to describe a dish of cooked calf or lamb pancreas. That name may have been derived from the Old English word braed, which means "flesh."

On June 2, 1975, several national cricket matches were postponed due to snow showers. The lowest summer temperature ever recorded in the UK was -5.6 °C on June 9, 1955, in Dalwhinnie, and it was again recorded on June 1 and June 3, 1962, in Santon Downham, Norfolk.

This holy summit, perched in the gorgeous southern Hill Country, has been a paradise for people of many faiths in Sri Lanka for over a thousand years. The mountain is known as Sri Pada in Buddhism, which means sacred footprint, and is thought to have been left by the Buddha on his way to paradise. It is Lord Shiva's footprint, according to Hindus. When Christians and Muslims are asked, they will reply that is the footprint of Adam when he was expelled from the Garden of Eden. 

You’ve heard of monkeys and dogs in space, but did you know that a cat braved the great unknown too? On October 18th, 1963 Felicette, also known as ‘Astrocat’ was the first and only cat to go to space.

The Vaccinium genus includes huckleberries, bilberries, and blueberries, all of which are closely related to the cranberry.

Now for a positive fact about Taiwan. Compared to its neighboring countries like Japan, Korea, and China where LGBT people face discrimination, Taiwan is forward-thinking and progressive.

Doctor Strange was nearly not given to Benedict Cumberbatch. Despite fierce A-list competition from Justin Theroux, Jon Hamm, Ewan McGregor, Johnny Depp, Jake Gyllenhaal, and Jared Leto, it was Joaquin Phoenix's rejection of the role that allowed Marvel Studios to officially announce Benedict Cumberbatch as the best character fit for the role of Doctor Strange.

This species lacks eyes, heads, tails, mouths, and brains. They are still alive! They spend most of their lives entrenched in one place. Their bodies are covered in holes, which sea sponges use to pump water and filter out food particles!

When the African Lungfish is in danger of dying, it secretes a mucus cocoon and burrows up to 9 inches into the earth, where it breathes through a built-in breathing tube that leads to the surface. It is thus dependent on rainfall to breathe.

The pan shot, also known as the panorama shot, was invented in 1987, when panning cameras were first used in film production. Cameras used to be stationary, so you had to move the entire camera and tripod to get any movement. This was a significant step forward in filmmaking and cinematography as an art form.

Did you know that the longest river in the world is located in Egypt? The Nile River cuts through Egypt and about 95 percent of the population of Egypt resides along the Nile River. With much of the country being occupied by desert, this fact about Egypt isn’t all that surprising. 90 percent of Egypt is made up of desert and the River Nile divides that desert.

The ancient Egyptians divided Egypt into two lands, the desert, and the Nile Valley. Contrary to what you would think, upper Egypt is located in the South and Lower Egypt is north. That is because the Nile flows north towards the Mediterranean Sea.

Walt's personal favorite song was a ballad called "Feed the Birds," which is from the Mary Poppins movie and is one of the many upbeat hits from Disney films over the years. Richard Sherman, who wrote the song, claims that Walt frequently visited the Sherman brothers' office at Disney on Fridays and asked for a personal rendition of "Feed the Birds." Sherman recalled that the man "loved that song and knew it was the heartbeat of the whole movie."

We often get attracted towards the smell of the earth when it rains but have you have thought that rain too can have smell? But it does! Petrichor is the word that describes the scent of the rain. The reason behind it is that some plants secrete oild during dry periods & when it rains these oil get released into the air. And the aromatic compounds combine to create the pleasant scent of rain.

If you're curious about the origins of the word "cake," it comes from the Middle English word "Kake." This term was used in the Middle Ages to describe a flat and round bread that was baked on both sides. It sounds a lot like the cakes we have here. It is also closely related to other words like pastry or tarts. Not only are they similar in words, but they are also similar in other ways.