I live very close to a short bridge that is being added onto (maybe 70m). Right now it’s one lane, and they’re adding the second lane next to it. I have to cross it every day for work so I’ve seen daily progress and there are so many more steps than I would have thought. From giant staple looking things, to multiple layers of rebar, to hay?? Different coverings of thick plastic sheeting. Can anyone with knowledge or experience explain the different steps and the purpose of each?

A two-dimensional maze is laid on the floor. This maze is like one you might find in a kids coloring book. It has an entrance and exit, and a single path can be drawn to the exit. Instead of paths, this maze is composed of water pipes.

Suppose the maze is entirely filled with water and the entrance is attached to a pressurized water hose. In a small maze, the water would flow to and out the exit and complete the path. The water pressure "solved" the maze.

Is there a size of maze where the water pressure is not enough to solve? Can the maze be infinitely spread across the floor? Can it scale up as long as there is enough water pressure? Is there a point where no amount of water pressure would be enough?

So, sound is pressure waves moving through the air. But the air is moving anyway, especially outdoors. Why does this not greatly interfere with the transmission of sound, given they’re both movements of the same medium?

This feels like a stupid question but it occurred to me in the shower and I couldn’t think of an answer.

As the question says. I know myocardial infarction pain, stomach pain, and urethral pain exist. Is this true for all internal organs and each part of them? Say, the outside of our kidneys, or our lungs, or spleen, and others. Including our veins and arteries.

I'm studying radiocarbon dating and calculating an artifact's age using the radioactive decay formula.

While going through some examples, I saw one that mentions, "An artifact is found with 40% of its original carbon-14 remaining. How old is the artifact?" I understand the concept, but I’m a bit confused about how they determine the percentage, and what units are used to measure the amount of carbon-14.

Can anyone explain how the percentage is calculated and what the unit of measurement for carbon-14 here?

At night, when everything is dark, I often notice that some lights from outside the door can be seen only when i'm not looking. Another example is the switched off neon light, completely off when looking directly, can see a pale light with the corner of the eye.

I understand that symptoms of such diseases may only show up after the people have already reproduced, so there might be not enough evolutionary pressure on the single individual. But I thought that humans also owe a lot of their early success to the cooperation in small groups/family structures, and this then yielded to adaptations like grandparents living longer to care for grandkids etc.

So if you have a group of hunter-gatherers where some family have eg huntingtons, or even some small village of farmers, shouldn’t they be at a huge disadvantage? And continuously so for all generations? How did such diseases survive still?

So maybe I'm misguided in this but I've recently been learning about the insulin pathway and it causing GLUT4 to be takes into certain tissues to intake glucose. They mention in some videos that vertebrae's have developed this implying that at least some invertebrates do not have this insulin pathway?

So how do these creatures get energy into the cell?

My first thought would be that photosynthesis does not need insulin to make glucose useful to plants so there have to be some evolutionary processes that can facilitate this.

We can look out to other galaxies and see their shape, but we can't exactly see our own galaxy from the outside just yet. I know we can calculate distance to the galaxy core, and other stars, but do we measure star density in different directions to get a general position? How do we know that we are seeing the end or edge of a galaxy, how do we know how many arms spiral out from the center? Is the gravity of the supermassive black hole at the center responsible for the shape of the galaxy?

I know it sounds like a question for 6 year olds but Where does the heat go ? What I mean is short term the ground that would only work for so long as it would eventually heat up as well. The IR radiation from everything would cool us down but it doesn't seem like it would be so high and iirc the atmosphere absorbs a lot of IR already so it's not that. The atoms escaping our planet might be contain a lot of energy but very low in mass so they likely don't cool us down much so How does the heat escape us ?