6. Why does your face turn red when you get angry?
The reason why your face turns red when you’re angry is that your heart starts beating faster in order to send more blood to your muscles which helps you to prepare for a fight. The blood vessels in your face also widen to allow more blood to flow through them, and since they are very close to the skin, the extra blood flow becomes more visible.
Anger is the nervous system’s response to a threat. As soon as your nervous system detects some possible threat around you, the sympathetic nervous system activates a fight-or-flight response to the situation. The response prepares your body to either run away from the threat or to fight back. In case of anger, it is generally a fight response.
The response prepares your body for a fight by increasing the flow of blood into the blood vessels. Since the blood vessels on your face are closer to the surface of the skin and the skin is translucent, the blood becomes more visible, making your face red.
You also might have observed that the face of people with lighter color skin appears more reddish when they’re angry. Everybody’s nervous system produces the same response even if some people’s faces turn redder or some people’s does not at all.
Also, the response is involuntary as it is produced by the sympathetic nervous system and a similar response is seen when a person blushes or becomes embarrassed. It’s a human way of showing emotions. (1, 2)
7. Why do clocks run clockwise?
All clocks run clockwise because that is exactly how sundials cast a shadow in the northern hemisphere, and clocks are a direct adaptation of northern hemisphere sundials.
The first devices back then to measure time were sundials. In the northern hemisphere, it appears that the Earth rotates anti-clockwise because the sundials show shadow moving from the north to the east to the south and then to the west. Modern-day clocks were based on this principle as well and designed accordingly.
The situation would have been the opposite if the clocks were to have originated in the southern hemisphere because the sundials show shadows moving in opposite directions there.
It’s amazing to know that the clockwise direction of clocks is because of a mere coincidence. The clocks would have run in a counter-clockwise direction now if they would have invented in the southern hemisphere. (1, 2)
8. Why are school buses always yellow?
Yellow is the standard color for all school buses because it is the second most attentive color and can be noticed in the rain, fog, and dew to avoid accidents in such conditions.
The color red has the maximum wavelength and is already attributed to signals of danger. The second most attentive color after red is yellow, and therefore it is used for painting all the school buses.
Another reason for using yellow instead of red is that it is visible in the rain, fog, and dew because its lateral peripheral vision is greater by 1.24 times than red. The lateral peripheral vision helps a person to get a hint of the color even if he/she is not directly facing in the same direction of the color.
9. How do traffic lights work?
Traffic lights work with the help of a timer or sensor attached to them. Different sensors are used at different places such as induction loops, radars, cameras, lasers, etc.
The mechanism of the traffic lights differs according to the places. Generally, in cities, traffic lights work on timers embedded in them. There are intersections on roads so using the timers helps best to direct the traffic smoothly, whereas on country roads the traffic lights work on sensors inside them.
These sensors are good at detecting the vehicles that arrived at the intersection and directing the inconsistent traffic flow.
The most reliable and common sensors used for managing traffic are induction loops. These are just coiled wires embedded on the surface of the roads that detect differences in the inductance, providing information to the sensor circuit to produce signals. Other sensors involve microwave radar detectors and camera detectors.
10. Why does the ISS (International Space Station) never run out of fresh air to breathe?
The ISS never runs out of oxygen to breathe only because of a simple chemical technique, namely electrolysis. They use solar energy from the sunrays to produce electricity which separates the hydrogen and oxygen molecules. These oxygen molecules are used as fresh air to breathe.
Originally, water and food come from the Earth, but they are recycled and used many times. Astronauts receive water and air once in a while when they travel from Soyuz capsules, or they also receive these vital things via uncrewed spaceships. These are basically spaceships with literally no crew members.
One-time supply is not enough to sustain the needs of people on board, so they have to practice recycling extensively. The space station’s system is set up to recycle pure drinking water from wastewater, sweat, and even urine. Water is not just used for normal water-use purposes but to also make oxygen out of it.
We know that every molecule of water is a combination of one oxygen and two hydrogen atoms. This combination is breakable by a simple process called “electrolysis.” In electrolysis, electricity is passed through water which separates the two chemicals. Electricity does not come from the Earth to the space stations, they derive it from the solar energy of the Sun.
You’ll be surprised to know that the remaining hydrogen is again used for making water after combining it with the carbon dioxide exhaled by the scientists onboard. After combinations, another side product is made, which is methane, and it is of no use so it has to be disposed of in the space through special vents. (1, 2)