There are many questions that arise in our mind on a day-to-day basis, and we tend to seek help to find answers. Many of us use Google to find an answer to our questions.

1. How can mobile phones make “emergency calls” when there’s no network coverage?

The two most annoying things that cause frustration to mobile users are “low battery” and “no network coverage.” When you are calling someone, your call gets connected via the network coverage offered by your service provider. When pressing the call button, your phone releases a signal which is detected by the nearest network tower. The signal is then transmitted to the receiver’s tower, and finally, you are able to reach the person. Have you ever imagined how an emergency call goes through even during the absence of network coverage?

It is the general assumption that emergency calls can go through without a network, but it’s not true. SIM cards usually work on Global System for Mobile (GSM) technology. The GSM technology enables the utilization of signals from the nearest tower even when provided by another network service provider. This mechanism of using another network service provider’s tower facilities enables a user to make emergency calls. In some countries including the United States, it is possible to make an emergency call even with a dysfunctional SIM card. This is facilitated by the antennae that are present on your mobile phone. The antenna connects to the nearest tower rather than your SIM card.

2. Why does plastic turn white when you bend it?

Polymers, like plastic, turn white when they experience stress by color-change reactions known as “stress-induced crystallization.” It is a known fact that many polymers are semi-crystalline (neatly ordered) and amorphous (unordered). When plastic is bent, the polymer chains start rearranging themselves according to the direction in which it is bent. The polymers chains get closely packed and aligned during the reorientation phase.

When the white color appears on top of the plastic, this is due to the elongation of the polymer chain on the top side. If the color change is observed on the reverse, this is due to elongation of the chain on the bottom side. If the process is repeated a couple of times, the plastic breaks due to repeated stress induced on the polymer chain. If the polymer chain is tangled, then the plastic can further be elongated. It is important to check how polymers perform under stress in order to make good-quality products.

3. In a cup of coffee, why does the top of the liquid leave a stain ring, whereas the rest of the liquid does not?

If you are a coffee lover, you would have noticed that your favorite liquid leaves a circular stain on the top of the mug. Have you wondered why this occurs? Well, we have the answer for you. Based on a study published in the science journal Nature, researchers were able to determine the movement of particles.

The particles in coffee move towards their perimeter forming a dense ring around the edge of the liquid. When coffee evaporates, these particles do not evaporate and stay in the same place. The particles also tend to remain in the same place when the volume of the coffee decreases. In another study, the researchers were able to determine that the shape of the coffee particle is spherical. These particles tend to spread easily towards the edges when compared to other shapes.

4. Why is it when you rub your eyes for long enough, you begin to see shapes, grids, and other stuff?

Everyone has experienced a weird display of fuzzy colors, swirling visuals, and checkerboards after squishing your eyes. Why does this occur? Scientists have identified this phenomenon as “phosphenes.” One experiences light sensations without the light actually entering into the eye. This commonly arises due to pressure phosphene.

The human eyeball is comprised of many types of neurons called “retinal ganglion.” It is responsible for receiving the visual information from the light-sensitive photoreceptors cells in the retina. However, it can also be activated by applying pressure on the eyeball and tricks the eyeballs into activating a similar phenomenon.

5. Why do pen caps have holes in them?

One of the most common thing which we notice on a day-to-day is the hole on top of the pen caps, but why do they have them? The pen caps have holes in them to prevent suffocation in case they were swallowed accidentally. According to various reports, pen caps are considered to be the most common thing swallowed by children. This can cause potential choking and prove to be fatal. Pen caps with holes were designed to allow passage of air through the holes if they are accidentally swallowed by children. After knowing the reason behind it, pen caps can be considered as superheroes in disguise.

6. Why does water appear white while going over a waterfall?

We all know that water is colorless, but why does it appear white while going over a waterfall? Water that is flowing in canals and rivers appear muddy, however, it turns white as the water gets aerated when falling from a greater height. The flow of water changes from a laminar flow to a turbulent flow. Turbulent flow is usually rapid and is a non-uniform flow.

Water falling from greater height moves at very high speeds and contains trapped air that creates bubbles with dissolved oxygen. The rapid water movement causes dissolved oxygen to evaporate releasing oxygen in its gaseous form. Thus, these aerated bubbles make the waterfall appear white when falling from greater heights.

7. Why do airlines have ashtrays in the toilets when you can’t smoke?

Planes have a strict “No Smoking” policy in place, but why then do they have ashtrays in their toilets? Smoking in planes was banned in the 1980s, but seeing ashtrays in toilets raises a concern of safety. One might tend to think that the planes might be old as they still contain these ashtrays. However, this may not be a reason for concern as it is mandated by law to place them in airplanes.

8. Why can’t bots check “I am not a robot” checkboxes?

The OCR process is tedious and the bots are capable of bypassing the validation check. But the mouse movements tend to identify them. Human-controlled mouse movements are usually jerky, whereas the movements made by bots are very smooth and precise. This technique of comparing the live mouse movements against sample data ensures that bots are not granted access to the page. If it fails, the reCaptcha system generates a difficult captcha that requires more recognition of the context of some displayed scenes.

9. Why is it so difficult to type or move your fingers quickly when your hands are very cold?

The small blood vessels that are present in our fingers constrict when the temperature drops to preserve heat. Due to this constriction of blood vessels, the nerves in our fingers become less responsive, and the fingers turn numb. Due to the cold, the chemical reactions needed for contacts take a hit as well. This feeling of numbness decreases finger agility making it difficult to type or do other activities.

10. Why does traveling make you feel so tired when you’ve just sat there for hours doing nothing?

Why do we tend to feel tired while traveling though we are literally sitting down for the entire duration? The feeling of tiredness one experiences during traveling by train, bus or airplane if subjective and differs for every person. However, there are certain factors that impact the comfort of a passenger while traveling. Firstly, the constant moving of the vehicle while traveling on roads tends to wear one out. This can be further fuelled by sudden jerking movements during braking, acceleration, and the quality of the roads.

Secondly, being seated in an upright position in a constrained place for a long time tends to stress out your muscles. Thirdly, dehydration is a major factor when you are traveling by airplane. The cabin pressure is changed frequently to ensure that there is adequate breathable air. This is further fuelled by turbulence, noise, vibrations and constant movement disturbs the body’s natural rhythm. Finally, psychological factors cannot be ignored, people tend to get wary with the notion of long-distance travel.