6 Why do you blink when there is a sudden loud noise close by?

Given the delicate nature and usefulness of eyes to both humans and animals, the brain acts spontaneously to make sure that the eye protects itself. Often, a loud sound is associated with danger, so when the door bangs, eyes blink in an attempt to protect the eye from any dust or particles. The condition is known as the “acoustic startle-reflex eye blink.” Eye blinking when you hear a loud noise or intense light happens fast without having a second thought about blinking.

When there is a loud noise, the ears and eyes send messages to the subconscious part of the brain using sensory nerves. The mind, in turn, commands the nerves controlling the eyelid to close the eye. (source)

7 What causes the northern lights?

Aurora borealis, the name given to the northern lights, is a fascinating phenomenon that was once associated with spooky ghosts, gods, and/or fire bridges. The formation of the northern lights is more fascinating than its spooky association. The Sun, 93 million miles away, creates Solar wind. The Solar wind travels through space into the Earth’s atmosphere. The magnetic fields on the surface divert the Solar wind away from the Earth’s center towards the North Poles and South Poles. As the Solar wind moves towards the North Pole in the atmosphere, its protons and electrons collide with particles in the atmosphere. The energy generated during the collision causes the northern lights, also called aurora borealis.

The different particles in the air cause the different colors seen in the northern lights. Nitrogen, when excited by the Solar wind, generate blue or red colors. On the other hand, oxygen produces a green color when excited. The northern lights can appear in Alaska, Greenland, Iceland, Finland, Russia, Sweden, Norway, and Northern Canada. Northern Lights are always there, but the best time to get the full view is during March, April, September, and October. (1, 2)

8 Are the colors you see the same as the ones I see?

Imagine looking at a particular color with your friend, and suddenly your friend sees the color blue while you see something else. After years of head-scratching and thinking, scientists agree that humans could have a different perception of colors and that various factors surrounding the color determine the judgment. An average human has three photoreceptors that identify green, blue, and red colors. However, some people have four photoreceptors instead of three. Scientists call them “tetrachromats.” Tetrachromats can see a color between red and green and will argue that all other persons that do not know that color are color blind.

The difference in light wavelength depends on a few other factors as well. perception, moods, memories, feelings are some of the factors that contribute to people seeing colors differently. (1, 2, 3)

9 Why do we puke/vomit? 

Vomiting/puking is a reflex action that occurs involuntarily. You have no control over the action. Different factors like swaying motions, stress hormones in the blood, chemicals, and stomach upsets contribute to vomiting. The chemoreceptor trigger zone detects these factors that cause vomiting in the brain. It then alerts the body causing it to vomit.

When you are about to vomit, the salivary glands produce vast amounts of saliva filling the mouth with saliva. The reason why the salivary glands produce more saliva when one is about to vomit is to protect the teeth and the mouth from the acidic contents from the stomach as you throw up. The diaphragm contracts and breathing ceases for a moment. The reason is to protect the lungs from the vomit. Also, the abdominal muscles increase pressure on the stomach to ensure maximum ejection of unwanted content. Remember, the urge to vomit is often referred to as “nausea” and doesn’t necessarily lead to puking. (1, 2)

10 How do they manage to continually provide hot water to all the rooms in significant buildings like hotels?

In the hospitality industry, offering satisfactory service to a customer/client is vital for business success. Hot water in hotel rooms is one of the excellent services customers enjoy. Many-story buildings need vast volumes of water to ensure that there is enough of a supply of hot water in the showers and bathtubs. Installing a hot water system is costly, especially in large buildings. To ensure that there is a cost-effective hot water system, hotel owners have applied technology.

The larger buildings like hotels have industrial-size water tanks filled with hot water, typically at 120 degrees Fahrenheit and three-way domestic water pipes. The three pipes carry cold water, hot water, and a hot water return to form a loop. The water then circulates continuously, and it is returned to the hot water tank if it doesn’t get used. Also, the larger buildings use instantaneous water heaters to ensure that there is a continuous supply of hot water during the peak hours which is usually in the morning. (source)