Why does alcohol leave a smell on our breath?

The smell lingers as long as you're drunk because it's not coming from residual booze in your saliva, it's the smell of your blood itself.

When you imbibe an alcoholic beverage, ethanol (the active ingredient that gets you drunk), is absorbed into your bloodstream. Ethanol is a volatile chemical (it evaporates easily), so when alcoholic blood passes through your lungs, some of the ethanol evaporates into the air that you exhale. It's this process that allows a breathalyzer to measure BAC based on your exhalation.

Why are things shiny (or shinier) when wet?

When you look at anything, what you're really seeing is light bouncing off of that object and then traveling to your eyes. When light strikes a surface, it will reflect at the same angle that it struck the surface at, 100% of the time, according to what is known in optics as "the law of reflection".

Now, look at the nearest flat surface. It looks perfectly flat, but it isn't. If you zoom in, to a molecular level, you'd be able to see that the surface is really, really bumpy. Imagine playing ping-pong on a table that wasn't flat but was instead covered in bumps and deformities. When the ball hits the side of a bump it wouldn't reflect and keep moving to the other side of the table; it would probably be deflected to the left or the right or maybe even straight back to you. The exact same thing happens with light: when it strikes the surface that's bumpy at the molecular level, it can bounce in pretty much any direction.

Most dry surfaces are pretty bumpy, but water likes to lie flat and isn't as bumpy as those surfaces. When light strikes the water, it's more-or-less deflected all in the same direction because now the surface is much smoother. This is why wet things are shiny: because the water is making the surface smooth (again, on a molecular level) which makes any light that strikes it reflect not randomly, but in the same direction.

Why some animals seem to enjoy human affection?

Some animals are social animals. In the wild they would live in packs, herds, or groups. We domesticated some of these animals and we become their pack members or herd members. They want attention and since humans give it to them (and give them food also) they bond to us.

Not all animals that live in packs can be domesticated and behave too wild as they mature so we don't keep them as pets or livestock.

Noting that when these animals which seem to enjoy our attention are not raised by humans (but live wild/feral) they don't crave human attention at all and instead find companionship with other wild animals of their own kind. Wild horses will run from people, feral dog packs will even attack people. Feral cats will run away from people.

Great Tips for Amazing Presentations

Speaking in front of a crowd can be a nerve wrecking experience. Some people rate the fear of public speaking to be as horrifying as the thought of death. However, if you are well prepared with your presentation, then it will not be as bad as you think

Here are some tips you can use for your next presentation to ensure that you hold onto the attention of your audience and deliver your information to them effortlessly and more efficiently.

Presentation Structure

Structuring your presentation is the most important piece of the puzzle. To create amazing slides, use software tools, seamlessly incorporated with your data. Tools should have tutorials to help you learn to use them, how to add a background in a PDF, or how to load an image onto a PowerPoint slide are all common queries that have easy fixes.

Once you have got a hold of making impressive slides, it’s important to know how many slides to make. The 10-20-30 rule by Guy Kawasaki is the best rule of thumb to use for structuring your slides. The rule states that you should have ten slides for every twenty minutes of speaking and never use less than 30-point font in your slides. Some experts say that the threshold for the number of slides in your presentation can creep up to the twenty mark. However, the more slides you end up creating, the more you run the risk of losing your audience’s attention, or inundating them with too much data.

Keep your slides as straightforward and practical as possible. If you can spell your keywords and key points out on a slide, then you probably should consider reviewing your presentation and creating points that are condensed and easier to follow.

Tips for Your Physical Presentation

Your physical presence is the most important component. You could have rubbish slides, but if you know what you are talking about and have the ability to hold the audience’s attention, then you have a better opportunity of increasing engagement. Your tone of voice should be happy and enthusiastic, without being comical. Avoid using a flat or droning vocal tone as this will cause your audience to zone out almost immediately.

Open your presentation with a light-hearted statement, or a brief story that has a bit of humor in it and maybe cracks a laugh from your audience. After breaking the ice, launch into your presentation and remember to make eye contact with the crowd. Don’t hold your gaze on anyone, rather move from one person to another, holding your gaze on one person will make them feel uncomfortable.

Always remember to speak clearly and slowly. If there are any questions during your presentation, try to answer them as quickly as possible, or tell the audience member that you will handle their query at the end.

Wrapping Up

Public speaking does not have to be a hassle. If you do the work beforehand and have all of your ducks in a row, then your presentation should run smoothly.

Why do Asian countries have a much smaller rate of obesity than the US?

There are genetic predispositions involved in obesity, but also considerable differences in diet and culture.  

Obesity has been growing a lot in China, as its food supply industrializes and Western practices like using cheap, non-natural sugars in packaged foods increase.  

However, it doesn't seem to be an issue in Japan or South Korea, where cuisine is strongly cultural and not just based on economics.  Food preparation and balance is taken very seriously, in ways that are similar to French and Italian culture, but with very small portion sizes.

There is also a cultural emphasis on shame, so an obese person is more motivated to take whatever measures may be necessary to lose weight, whereas there is more of a rationalizing and individualist view in most Western societies.  

Shaming a fat person is unethical in Western culture while being one is ethically neutral (except in that maybe you cause people who care about you to worry for your health), whereas in Japan, being fat could be considered mildly unethical because you may be embarrassing your family and the people you're associated with.

Why is handwriting from the past so much prettier than writing now?

People didn't have much in the way of alternatives before the typewriter was invented. There was a great emphasis on having clear, legible handwriting.

People either wrote by hand or not at all. So there was a lot of emphasis on having good handwriting in letters and documents and people just got better at through sheer amount of practice they were getting.

Now since the advent of keyboards no one cares about handwriting anymore and it has been antiquated outside of signatures. Keyboards do the same thing perfectly every time with less effort.

Why Americans use drywall instead of concrete and bricks to build houses in areas prone to natural disasters?

The only natural disaster that concrete and brick houses are better at dealing with are fires.

With tornadoes most damage is done by winds so strong that they dismantle concrete, brick, or stone either directly or by throwing debris into them only slightly more slowly than they do wood. You can make a tornado bunker that is above ground with 4 foot thick walls and steel reinforcement. Homes do not do that, even in places that they make concrete homes.

Hurricanes tend to do most of their damage with flooding. Concrete and Bricks flood and mold just as easily as wood. When they are washed away the ground itself is washed away so they break just as easily too. For the extremely powerful hurricanes we have the same wind issues as tornadoes.

For earthquakes the concrete and brick homes are far worse than wood. They are too rigid unless very expensive tech and building practices are used and so they just crumble when an earthquake happens as they cannot flex.

And finally they are 3-10 times more expensive than wooden homes. Chances of you actually losing your home in your lifetime are low, and you get insurance to protect against it. So it is far better for most to spend what money they have to build a larger nicer home.

Also, drywall is not a structural weight bearing material. It is the interior finishing of the wall. Wood is the structural component and wood/fiberglass is the outdoor wall slat.