# Flow of water vs mercury vs treacle

• vorcil
In summary, the conversation discusses the relationship between volume flow rate and the height of a hole in a water tank, and how it is affected by different liquids with varying densities and viscosities. The formula Q = Pi*r^2 * (squareroot 2gh) is used to calculate the velocity of the water jet, but it may need to be modified for liquids with higher viscosities, such as honey or pitch. This is demonstrated in the famous pitch drop experiment.
vorcil
Imagine a hollow cylinder filled with water (a water tank)
a hole is near the bottom of the cylinder

the hole is covered, the tank filled with water and then the hole is uncovered

the volume flow rate = Q
h = the height of the hole from the water level

Q = Pi*r^2 * (squareroot 2gh)
(i solved this from)

q=av (area * velocity)

area of cylinder = pi R^2

velocity as it leave the hole = Squareroot (2gh) -> (h being the height from the hole to the water level)

after doing the experiment and graphs and stuff i got the velocity of the water jet to be 2.816 ms^-1

question:
would the velocity be different if i had mercury in the cylinder instead of water?

i know the velocity is determined by $$\sqrt{}(2gh)$$
so the density and mass of the liquid shouldn't make a difference!

but that made me think, what if i put something like honey or treacle into the cylinder.
it would definitely be slower, So wouldn't $$\sqrt{}(2gh)$$ be wrong? even though my textbook says to use that formula?

## 1. What is the difference between the flow of water, mercury, and treacle?

The main difference between the flow of water, mercury, and treacle lies in their viscosity, or resistance to flow. Water has a relatively low viscosity, meaning it flows easily, while mercury has a higher viscosity and treacle has an even higher viscosity.

## 2. How does the flow of water, mercury, and treacle affect their movement through pipes or tubes?

The flow of water, mercury, and treacle can all be affected by the size and shape of the pipes or tubes they are flowing through. Water, being less viscous, can travel through narrower pipes more easily than mercury or treacle.

## 3. Can the flow of water, mercury, and treacle be influenced by external factors?

Yes, the flow of these substances can be influenced by external factors such as temperature, pressure, and gravity. For example, mercury has a lower viscosity at higher temperatures, making it flow more easily.

## 4. Which substance has the slowest flow rate?

Treacle typically has the slowest flow rate due to its high viscosity. It will take longer for the same volume of treacle to flow through a pipe compared to water or mercury.

## 5. Are there any practical applications for studying the flow of water, mercury, and treacle?

Studying the flow of these substances can have various practical applications, such as designing efficient plumbing systems, understanding the behavior of fluids in the human body, and developing new materials with specific flow properties.

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