How big is a milliliter....I mean is it 1 eyedrop like from an eyedroper or is it the whole eyedroper (Which seems to hold around 5 drops)
thanks
thanks
How big is a milliliter?
- Thread starter CHOPPER GOD
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1 milliliter is 1/1000th of a liter. Seeing how 1L = 0.264172051 US gallon, 1 milliliter = 0.000264172051 US gallon. That's not a whole lot.
It's 0.00211337641 US pints.
And it's 0.0338140226 US fluid ounce.
(That gives a median of 48.6 microliters.)
I'd say that's conclusive enough. Interestingly, there are about 76000 drops to a gallon. Google Calculator to prove it
Generally, the rule of thumb is 20 drops per mL (as kevin showed above).
If you're an average person, you can stop reading. However, if you're an HT regular, the size of a 'drop' will depend on the substance you're dropping and the material that the dropper is made from. A drop is formed when surface tension forces between the fluid and the dropper exceed the shear forces of the fluid flowing down the dropper. Because the size of a drop is not constant, it's not necessarily correct to say that 20 drops is 1 mL. This correlation has been developed for water in most glass or plastic containers though and does stand up to muster as long as your materials are not too strange.
If you're an average person, you can stop reading. However, if you're an HT regular, the size of a 'drop' will depend on the substance you're dropping and the material that the dropper is made from. A drop is formed when surface tension forces between the fluid and the dropper exceed the shear forces of the fluid flowing down the dropper. Because the size of a drop is not constant, it's not necessarily correct to say that 20 drops is 1 mL. This correlation has been developed for water in most glass or plastic containers though and does stand up to muster as long as your materials are not too strange.
thanks guys...i was giving my cat some medicine and it says to give 1mL and i gave her the whole eyedroper...no way in hell i give her 20 drops as the 5-6 that fill the eyedropper really seemed to knock her out.....
In true HT fashion...
Yes. Let's assume earth's gravity and the air pressure aren't changing so the specific weight and surface tension aren't changing for a given substance. Let's also assume that you have a constant dropper size to keep things scientific. We're holding it at a constant angle to neglect the effects associated there too.
Surface tension force goes up in a linear fashion with an increase in radius (because it essentially goes up with the circumference) but weight goes up in a cubic fashion (because it essentially goes up with the volume). The point at which these two forces overcome one another is the time when the drop drops, but that's not quite complete either. The drop size changes as the volume increases. Initally, your liquid is entirely supported at the dropper's radius, giving it a very good radius of surface tension for a comparably low volume, but eventually it elongates to almost form a sphere before it drops. I would suppose a good combination of CFD and FEA would be appropriate here, and I'm not even sure if you can assume steady state analysis unless you're holding the dropper very still and squeezing very slowly.
This reminds me of the difficulties in predicting bubble density for my studies in pool boiling heat transfer on a horizontal plate with vertical normal orientation. The surface tension at the nucleation between the fluid and the vapor is what causes it to stay close to the heated wall before releasing, and while it's sitting there the wall has to superheat quite a bit before it goes anywhere. (When it does release the cooler liquid can quench the wall.) Surface tension has big effect on bubble size. Studies have been done on the effects of surfactants on convection heat transfer coefficients and on the critical heat flux.
Actually, in general, 1 ml is not the same as one cubic centimeter, depending on how exact you want to get. One mililiter is defined as one cubic centimeter of water at 4 degrrees centigrade (the point at which water is most dense).
A PhD student in mechanical engineering here just published a paper on predicting droplet pinchoff using a relatively simple mechanical model similar to what you described. I'll see if I can track it down... The experimental setup he used was a microfluidic device that had an applied pressure gradient with a feed of liquid A on one side and fluid B on the other. Since the pressure gradient and dimensions of the system were all known, he could
My department (chemical engineering) does lots of work with bubble columns, so I get to see lots of seminars on this stuff. There are some pretty strange things people do with bubbles. Especially the guys from Holland.
I'd say it's about 100 eyedrops. I've worked with ~microliter volumes and I'd say that an eyedrop is about ~10microliters
huh? How are capacity and volume different? You might be thinking of the density of water. Comparing capacity with volume is independent of substance. Even at those different temperatures, both the capacity and the volume of that water is changing, but the mass isn't.
Well, it wasn't always the case. I think that's the point he was making. These days, everything stems from basic relationships among metric units, and in fact, all the US Customary units are derived from those standards.
KevinTheNerd. Historically, when the French created the metric system they tried to create a uniform, rational system. Due to technological limitations they got some of it wrong. The meter was based on the distance from the north pole to the equator (1 ten millionth of the distance). Both grams and liters are based on the property of water. The original plan was that one cubic centimeter should equal one mililiter and one mililiter should weigh one gram. See, e.g., Origin of the Metric System.
well I usually think of ml as 1 gram. 5 grams or ml are in teaspoon. Mliters/liters are used for water or volume whereas grams/kilograms are used for measuring total weight, lets say a weight of a solid.
This is most incorrect.
The whole point of defining a temperature of the water is to avoid this whole situation.
But 5 g of steel is much less than a milliliter. In your approach is the implicit assumption that density of the substance being measured is equal to that of water.
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