Water Definition and 1000 Threads

I am using some solved excercises to put homework to my students but I cannot understand the proposed solution for c) a) $$ Q= 400 l/min = 6.67 ·10^3 m^3/s $$ applying continuity equation: $$ Q = S_1 v_1 \Rightarrow v_1 = \frac Q S_1 = 4.19 m/s $$ This is exactly the same as the proposed...

What will be the boiling point of the fully filled water in a vacuum container? Let's say I vacuum the container first, then fill it the water in it from water reservoir of same vacuum level

Hello people! What were the purpose of these things on this dam? LOC Thanks!

Since charged particles like electrons are the source of electromagnetic waves how could an electron in water for example moves faster than the speed of light inside water c/n I mean how could the source moves faster than the field it creates because then the fields velocity will become larger...

This is a water spirometer. You have to exhale as hard as possible the pulley rotates and the pointer shows the volume exhaled. The procedure wants us to keep the pointer at 400 and later subtract 400 to get the correct volume. Why can't we start at zero? Teacher says it is easier to exhale...

How Woman Turns Sandy Desert Into Fertile Farmland - Water-Saving-Method My wife was watching the following video the other night. I sounded interesting and timely, especially for the western US and parts of Mexico, e.g., the Sonoran Desert. How This Woman Has Restored Dry Desert Rivers...

Hi, I am trying to do some experiments with cavitation bubbles by generating a spark under water however I am having some trouble and was wondering if anyone would be able to help or offer some advice. The problem I am having is I cannot generate the spark consistently. I place the electrodes...

Hi. If we wanna train inside a water pool like just play fighting, how much depth that we need to simulate an altitude at 16000-18000 feet? Thank you.

I found an opinion that TPW (kg/m2) and PWV (mm) are the same thing, but I only found that kg/m2 = 1 mm and did not find any sources confirming that TPW=PWV. How valid is this? And if they are different things, how do you calculate PWV? P.S. In general, I need to get the PWV from the data of...

Energy required to evaporate water. Given 3 evaporating scenarios: 1. Glass filled with 50cc of water at 20C; the water is heated to 60C 2. Glass filled with 50cc of water at 20C; the water is heated to 100C 3. 50cc of water at 20C wiped over a large plate to create 50micron thickness layer...

We are trying to control a container with water inside. The container has two phases of operation. In one phase, the container is tilted. In this tilted state, the distance from the observation point (red dot) to the surface of the water (distance B) is known from a measurement device. However...

Imagine we have a cylinder filled with water with a closing mechanism, the height of the cylinder is quite large to create increased pressure at the very bottom. If the mechanism closes a small part at the bottom of the cylinder, will the pressure decrease or not? Thanks in advance for the answer

Hi folks, I am looking to solve a small issue. It requires a 'valve' that will permit water travel in one direction whilst under low active pressure but which closes upon cessation of said pressure. Fair enough....but when closed I would like it to allow air into the system (downstream of the...

[Mentor Note: Thread moved from the schoolwork forums to the technical forums, since it appears to be a real-world problem] If I have a water well 55m deep I want to suck water by gravity without any pump. I put a barrel of 85 liters and connect it firmly to a pipe of 55m length going into...

I took water from my schools water recycling filter. It looks like this (image 1): After filling my water bottle. I didn't drink from it and just left it untouched in my bag. After few days I took it out and it looks very unclear and some dust like metarials are floating inside the water. This...

My current pipeline is open ended on each side meaning I raise water level in a creek to create natural flow to the inlet and the outlet discharges from my pipe directly into a surface ditch. The surface ditch is well cleaned so that the top of the pipe is above water level at discharge meaning...

If we had a perfectly isolated glass of water, the total pressure inside will be equal to the sum of hydrostatic and static pressure. In this case, would the static pressure be totally dependent on the temperature of water and the volume of glass? Also, consider that the glass is completely...

I make Hummingbird feed by mixing 1/4 cup granulated sugar into 1 cup of water. I use a small glass pyrex measuring cup with one cup of water measured. It's heated for 1 minute in a microwave and 1/4 cup of sugar is added (no red dye!). I then vigorously stir the sugar and water using a metal...

Don't reply too quickly, I've seen a lot of answers on this question already (differing ones of course, what would you expect), at first sight it would seem to be really simple but there are quite a few complicating factors. So the question is basically: what's the quickest way to fill up a...

Hi, Case 1: Imagine a steady liquid water jet with unit cross sectional area - incompressible and inviscid. density D and uniform velocity V. Operating atmospheric pressure is 0.0 Pa. The jet is in air ( no air resistance ) and hits a stationary flat plate perpendicularly. Applying momentum...

Is there any friction coefficient in the sea as there is in ground? I've tried searching but I see results between 0.4 and 25.7 (?). If there's no such thing as a coefficient of friction to water, how do I calculate the amount of force to start moving a X mass object in water?

Hi there! I'm looking for an approx. minimal size for a drain channel where condensation water can go through. Can anyone have some advice? No increased pressure for the water, just the normal atmospheric pressure. Water condensing and just have to be able to get out. The amount of water is...

When water is moving does the actual freezing temperature change or does steam etc not freeze because warmer water keeps getting brought to the surface? Or is there something else going on that lowers the freezing point as long as the water is in motion? There are several reasons for my...

How much 45% phosphoric acid (in ml) would it take to raise PO4 by 1ppm in 1 litre of water? I need to be sure as fish are involved. It will be administered over a 24 hour period.

Let us say that the glass isn't whole under the water. If the height of the air layer under the water is ##\Delta x##, then the pressure the water acts on the gas is ##p=p_{\mathrm {atm}}+\Delta x \rho g##. But my confusion is why the "hydrostaic pressure" is ##\Delta x \rho g##, not ##L\rho...

[Mentor Note: Two duplicate threads merged...] in container with dimensions L×D, rests water of height H and density ρ. we disturb the water along L dimension, and accept an oscillation is caused on the free surface of the water, which maintains its flatness, so that the central of mass of the...

I add a little malic acid to my water to flavour it. I was wondering if it was ok to also add a drop of ethyl butyrate to see what it tastes like. I've found it here, https://www.ebay.co.uk/itm/234612863061

I would think the first solution is correct but the provided solution to this problem suggests the 2nd solution. Let me know what you guys think about this. Thanks,

Minerals in my city water deposit as white uneven layers on the metal bowls typically sold for watering dogs and cats. They also deposit that way on the metal bowls that I use for feeding humans. However on my two Nordicware brand cake pans (used as water bowls for cats) minerals deposit...

Hello all, For a project I really need to know some number i can't seem to produce myself. we are flashing water @75 degrees Celsius, the water after flash-cooling is 67 degrees constant pressure is 0.27 bar (absolute) flow rate is 15000 KG/per hour. how much water is vaporized? Help is much...

I just happen to see a show about air pressure host by Brian Cox. As the link:https://i.stack.imgur.com/vfZlI.jpg shows, he flipped a half-filled water cup upside down then the paper on cup doesn't drop: It puzzled me, because the cup is half-filled, the pressure shouldn't balance since inside...

I boil water in a tea kettle. When it's starting to boil there are pinging sounds. These grow louder until there is some sort of phase transition and they quiet down. That's about when the tea kettle starts to whistle. What's going on?

Hello, I am trying to throw water the furthest distance possible from a garden hose and an inline water pump. The amount of water is not important - e.g. a tiny stream is perfectly fine, so long as it reachest a really far distance. I understand wind severely messes this up, so lets not worry...

I'm interested in the very basics of drag, both for ships in water and airplanes in air. Here's what I have so far : Flow of the medium can be laminar or turbulent. As the relative speed of the vessel increases, the more likely the flow is to be turbulent. Laminar drag increases linearly...

Hi togehter, this may be an easy one for most, but I'm really struggling with imagining the process. Suppose we have a compressed air vessel that is half filled with water. The pressure in the vessel drops from 10 bar to atmospheric pressure within a few seconds. How does the water surface...

Hello everyone; Please need some help to check if my calculation are correct (and if possible some explantation) Bernoulli's equation between point 1 and 3 is given by: P_1+1/2 ρv_1^2 + ρgh_1 = P_3+1/2 ρv_3^2 + ρgh_3 P_1 = P_(atm ) v_1= 0 m/s h_1= 0.875 m P_3 = P_(atm ) v_3= ? m/s h_3= 0...

A typical UK domestic hot water tank holds c. 200 litres of water. Hitherto the common method of heating it to say 60C has been by means of an internal coil of copper pipe through which is pumped hot water from a gas boiler at ~ 70C. Heat transfer on the outside of the coil is by natural...

Hi! This project involves both mechanical and electrical elements, so I'm discussing it in this forum since I'm not sure which one it would fit better into. I'm working on an experiment in which I'm trying to measure the speed of sound through water. The approach is simple: I have a long...

Hello, I've heard versions of these statements (below) from other scientists, but I've never seen anyone break them down. Do molecules in air really move (diffuse?) their way around the entire globe, or are there localized "pockets" that really don't move that far from home? Intuitively, water...

Here’s the data is can supply. Water temperature entering ~51°C. desired water exit temperature ~38-40°C Water flow ~approx. 300L/min. Pipe Inside Dia.- 51mm Pipe Material- HDPE PN16 We would bury the pipe around 1 meter deep. Deeper is not feasible as the trenches would be hand dug in an area...

in solid form (the salt that is)? I had to try to answer this question for my 14 y/o cousin and think I may have messed it up. Good thing she knows I suck at science and to ASK HER TEACHER next time! :smile: Anyways, it got me curious. . .I first thought of just reversing the process. Since...

Water line on a certain property has been busted for 2 years and no water in line. I am calling plumber tomorrow to get fixed and am just curious before I do that if fact that there has been no water in line would pose any particular issue to plumber just coming out and fixing that one spot...

What about water makes it such a great substance? I'm aware of properties like a high SHC providing aquatic habitats with stability, being a liquid at room temperature due to Hydrogen bonding and etc but what about water makes it so great why is it such a miracle substance, solely because of the...

Taking the shape of water drop to be spherical with radius R and ignoring the gravity, three forces acting on the surface of the water drop are 1) force ##F_o## in radially inwards direrction due to the outside pressure ##P_o## 2) force ## F_{in}## in radially outward direction due to the...

I understand how to measure specific gravity of a rock. One weighs the rock then tares a beaker of water and then suspends the rock on a string to observe the “weight” gain of displaced water. My brain however could never get how, without adding a drop more water or adding the mass of the rock...

For this, Dose anybody please know where they got the 120W from? Many thanks!

I'm starting with a litre of distilled water with a dissolved oxygen content of zero ppm, and I wish to raise the ppm of the dissolved O2 to 10ppm or 10mg/L using a 6% solution of H2O2. That is 10 extra molecules of oxygen in a litre! I've had no luck looking for through web based conversion...