Tag Archives: Science

Why does a laser pointer have a grainy pattern in the beam?

The light from a laser is coherent, all the waves of the same wavelength, color, and all in exact lockstep with one another. When the beam strikes a surface and bounces off and the wavefronts collide with one another and can reinforce and/or cancel one another.

The sparkle pattern of a laser can be compared to the choppy surface of a lake on a windy day as waves cancel and reinforce one another to the extent that no regular pattern of waves can be seen.

What would happen if air bubbles from a syringe are not removed?

The main risk with leaving an air bubble in a syringe is inaccurate dosing. With the syringe partly full of air, the amount of liquid won’t be accurate to the markings on the syringe.

Getting air into a vein isn’t a significant hazard unless it’s a huge amount – like a whole drip tube full or someone squeezes a drip bag in, including the large air bubble.

The air will circulate in the veins and reach the lungs where it will lodge and get removed in a few minutes. The lungs will filter out the air so it can’t travel to the brain except where there is also a “hole in the heart”.

If photons (particles of light) have zero mass, how can they exist?

It’s very natural here on Earth to equate the word “mass” with the word “weight.” In fact, in our everyday lives, we can usually get away with using the two terms interchangeably. A massive thing is also going to be heavy.

It’s actually more accurate to define mass as “how much work it takes to push the thing down the road.” Again, very similar to “weight,” just a subtle distinction.

If I’m trying to push an elephant on roller skates down the road, and attain a speed of, say, 35 miles per hour, I have to do a lot of work.

I can either do this work all at once, maybe by firing the elephant out of a cannon, or I can spread the work out over time, pushing the elephant gradually faster and faster until the desired speed is attained.

Later, I can calculate how much work it took to get my elephant up to speed. (There are measurements for this stuff like joules and newtons.) In the end, I will find that, regardless of my method — either shooting the elephant out of a cannon, or slowly pushing it — the amount of work required to reach 35 miles per hour was exactly the same. It takes a certain, specific amount of work to get an object of a certain mass up to a certain speed.

With a massless object / particle like a photon, there’s no work required at all. The photon does not have to “explode” out of its flashlight as though it was shot from a cannon, it does not have to gradually accelerate over time, it’s already there. The “work,” in a sense, has already been done. That is also the reason photons are always moving at 300,000 km/s. They never speed up or slow down, they pop into being already traveling at the speed of light.

What is a magnetic field flip?

The orientation of the natural magnetic field reverses once in a while. The field is currently getting weaker, this could indicate that it will flip in the next centuries.

A weaker field can be bad for some satellites and some astronauts. In rare cases it can affect the electricity grid as well.

None of this is a sudden process. The magnetic field will probably just continue to get slightly weaker within our lifetime.

What would happen when water is put into an unbreakable container and then frozen?

There is no rule saying the container has to break. All freezing water does is increase the pressure inside the container. Higher pressure may cause a different type of ice crystal to form.

So the answer is that the water still turns into ice; however, if it genuinely cannot break the bonds of the container it is trapped inside, it turns into a very different kind of ice than we’re used to seeing.

We currently know of 15 different solid phases of water, aka ice, with each type being distinct due to differing density and internal structure. The form you’re likely most familiar with is Hexagonal Ice which is what happens when water freezes normally under regular conditions. If you keep lowering the temperature of Hexagonal ice, it eventually becomes Cubic Ice; tweak the temperature and pressure further and you can create more kinds — Ice II, Ice III all the way up to Ice XV.

What are scientists doing to combat drug-resistant bacteria and superbugs?

A lot of the work that is done is preventing antibiotic resistance bacteria from spreading. They can become a huge problem in hospitals, for example. All it takes is one sick person to be admitted, and it’s possible for the bacteria in them to spread to other patients through a variety of routes. There are all sorts of new methods of sterilizing rooms and equipment, and routinely gathering samples from at-risk patients so you know early on if they’ve caught it.

There are lots of new antibiotics in development, but there are also other possible treatments being studied, such as bacteriophages. Bacteriophages are viruses that infect and kill bacteria, but aren’t dangerous for us.

Research is also being done on how, exactly, bacteria can survive antibiotics. There are a lot of mechanisms, such as the bacteria having an enzyme that changes the structure of the antibiotic, being able to “spit” the antibiotic particles out of itself faster than they can get in, or mutating so that their molecules can no longer be recognized by the antibiotic. If we know these mechanisms, it’s possible to try to develop new treatments that specifically target them.

How do scientists know that a rock is from space and not of earthly origin?

Depends on what it is made of. Meteoric iron is unique because metal doesn’t naturally make that kind of pattern on Earth.

Certain elements and compounds are reactive in earth conditions. Metallic aluminum famously doesn’t exist naturally on Earth. If we found a hunk of it that wasn’t man made, we’d know it wasn’t on Earth however many thousands/millions of years ago, or it would have eroded away.

This also applies to certain isotopes. If something radioactive is too young, it can’t be from Earth. Earth has a well known age and all the crap that was here has been aging all this time.

There are also more obvious signs. Something from space smacking into Earth has an impact. If a meteor slamsinto a desert, we’re going to find a lot of natural glass around the impact site. Entire forests have been obliterated by meteors.

Does a bullet shot into the air come down with a force strong enough to kill?

If you fire straight up in the air, no, it doesn’t fall with a strong enough force to kill. But that’s the caveat.  Straight up means the bullet tumbles down and it reaches a fairly slow terminal velocity, no different than if you’d dropped a penny from the same height.

But anything besides straight up (just at an upward angle) and it will still have a ballistic trajectory, will probably not tumble, and it will be moving at a velocity that will kill people.

A few years ago a 12-year-old died on the Fourth of July because a neighbor fired a gun in the air and the bullet came down into the boy’s head.

If light slows down passing through water, how does it speed back up when it comes out?

Imagine a big famous actor walking through a room. They travel at a constant speed that we’ll call A. The actor always moves at speed A, no matter what. When the room is empty, they’re able to walk into the room and out of it easily in a straight line

However, if the room is full of people then the actor can’t walk in and out of the room in a straight line. They keep moving at A, but because of the people they have to bounce around and take a much more circuitous path to get out of the room. This means that despite remaining at A the entire time, it took them longer to get out of the full room than the empty room.

The same is true with light. The light doesn’t ‘slow down’ in water. The light’s still moving at c. However, water is much more dense than air or a vacuum, so in order to make it through the water, the light has to take a much more circuitous path. Despite never changing speed, we as an outside observe perceive the light taking more time to cross through the same distance as a difference in speed, rather than what it actually is: the distance having changed.

Why are canned foods high in sodium? Doesn’t canning eliminate the need for preservatives?

Not entirely.

First, depending on the food we’re talking about, salt might be an inherent part of the process, either of canning in particular or just the food in general. Pickles? Olives? Gotta have salt. Salt is also a critical ingredient in any number of fermented foods, many of which are canned.

Second, salt is a flavor enhancer. Processed food manufacturers have tended to add loads of salt to a wide variety of foods for the better part of a century as a way of making their products tastier. Canned foods are hardly unique here.

Third, while canned vegetables are certainly saltier than their raw counterparts, they’re not necessarily as salty as you might think. One 30g slice of white bread has a little less than three times as much sodium as 28g of canned green beans.

Fourth, while canning certainly tends to kill biological organisms, it’s not magic. Some organisms are merely weakened. Some may even survive, though in small enough numbers that they can’t cause a problem if the food is eaten within a year or two. A little salt goes a long way towards ensuring that fewer bacteria survive, and those that do stay dormant.

But lastly, bacteria aren’t the only things that contribute to food spoilage. There are other chemical processes that have nothing to do with bacteria that can make food go bad, or at least lose quality over time. Discoloration comes immediately to mind, but that’s not the only thing. Flavors can change. Textures can break down. Foods can take on flavors from their containers. Salt creates an environment inhospitable to bacteria, to be sure, but it also tends to interfere with some of these other processes, making it useful as a preservative even in a largely sterile environment.