Google Answers Logo
View Question
Q: weights & measurements ( No Answer,   11 Comments )
Subject: weights & measurements
Category: Science
Asked by: chigung-ga
List Price: $2.50
Posted: 13 Sep 2004 11:20 PDT
Expires: 13 Oct 2004 11:20 PDT
Question ID: 400625
How many drops of water are in one gallon of water?
There is no answer at this time.

Subject: Re: weights & measurements
From: rainbow-ga on 13 Sep 2004 11:41 PDT
Hi chigung,

Since I cannot verify the following calculations to be accurate, I'm
posting these as a comment. If you find this information to suffice,
let me know and I will post it as an answer.

"Have students predict how many drops of water they can put in one
tablespoon. Provide them with eyedroppers, standard measuring
tablespoons and water. Have students keep track of the number of drops
of water they successfully drop in until the tablespoon no longer
holds anymore.
(Aproximately 500 drops of water will fill one tablespoon)
The following chart was used to figure the amount of atrazine allowed
in drinking water:
500 drops water in one tablespoon
8000 drops water in one cup
16,000 drops water in one pint
128,000 drops water in one gallon
640,000 drops water in five gallons
12,800,000 drops water in 100 gallons
128,000,000 drops water in 1000 gallons
1, 280,000,000 drops water in 10, 000 gallons" 

Fort Hays State University

"Let's say that you have a moisture detector in your basement sump
area that's so sensitive that it will respond to one drop of water in
the sump. You want to know right away 'cuz you've got valuable
furniture in your basement. This then becomes your standard - one drop
of water.
Now you have some ground water seep in. An ounce (100 drops, a quart
(3200 drops and finally a full gallon of water(128,000 drops)."


I hope that helps.

Best regards,
Subject: Re: weights & measurements
From: pinkfreud-ga on 13 Sep 2004 11:46 PDT
This may help:
Subject: Re: weights & measurements
From: guzzi-ga on 13 Sep 2004 17:11 PDT
There is unfortunately no definitive answer to your question.
Industrially I had a similar requirement when we were trying to meter
exact quantities of an adhesive. Not really surprisingly, the volume
of the drop (ie when it detached) was very dependent upon orifice
size, orifice shape, thickness of tube end, and material of the
dispenser. I seem to recall that our extremes were 5:1.

Water may be even more problematic because of it?s polar nature, hence
wetting ability. The purity can also make a great difference as too
will temperature -- the sound of hot water is different to that of
cold due to fluidity.

All that can be said is that using deionised water at a constant
temperature with the same dropper rate and the same dropper in still
air, will give you reasonably consistent drop size. Only then can your
question be answered. However, one could experiment with extremes and
say that the number of drops will be between two figures.

One final variation -- US gallons are smaller than real gallons (ie UK).

Subject: Re: weights & measurements
From: pinkfreud-ga on 13 Sep 2004 17:17 PDT

Regarding the "reality" of our gallons, I don't think it matters a
hoot in a rainbarrel, since "real" scientists use the metric system.

Subject: Re: weights & measurements
From: tornado2-ga on 18 Sep 2004 19:16 PDT
I just counted, using a water dropper and an OXO measuring cup, that
one half an ounce of water (or one tablespoon) is 261 drops.  This
would be 522 drops for one once.  A gallon is 128 ounces, so
128ounces/gallonx522drops=66,816 drops/gallon.  Note: the size of a
drop of water varies greatly depending on the size of the hole that
produced it and the force behind it.  So, I do not think you will get
a definitive answer.  Perhaps my drops were just larger than those
that rainbow's article used and so there are fewer per gallon.
Subject: Re: weights & measurements
From: willh-ga on 25 Sep 2004 16:18 PDT
"Drop" is not a unit of measure.
Subject: Re: weights & measurements
From: tutuzdad-ga on 25 Sep 2004 17:10 PDT
The answer, of course, is ONE.

Subject: Re: weights & measurements
From: tutuzdad-ga on 25 Sep 2004 17:14 PDT
Let me clarify...A drop of water has no standard unit of measure.
There is ONE big drop of water in a gallon container of water. Your
question is like asking "How many peices of ice are in a glacier?".

The answer is ONE -  it's just a really, really big one.

Subject: Re: weights & measurements
From: armydoc-ga on 30 Sep 2004 14:18 PDT
As stated previously, there is no one answer, because drops of water
may have different volumes. In medicine, IV sets are calibrated as
"drops per milliliter", or the number of drops through the set that
will deliver 1 mL. Pediatric sets may have as many as 70+ drops per
mL, and veterinary large animal sets 15 drops per mL. FYI, while a
drop is not a unit of measure, it does have a latin-derived
abbreviation: gtt, for gutta (pl. guttae) meaning "drop". Therefore,
IV sets are often compared by "gtt/mL".
Subject: Re: weights & measurements
From: willh-ga on 05 Oct 2004 08:42 PDT
yada yada. . . while a drop is not a unit of measure. . .  yada yda
Subject: Re: weights & measurements
From: subcodex-ga on 23 Oct 2004 22:11 PDT
The key to the answer is knowing the unit of measurement of a "drop".
This unit is the "minim". There are in a U.S. gallon 61,440 minims
[drops]. The British gallon, larger than the U.S. gallon, contains
76,800 minims [drops].

Drops vary in size and amount. But the quantity of the "minim" always
remains the same, this size being an agreed upon standard measure of
volume and capacity.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  

Google Home - Answers FAQ - Terms of Service - Privacy Policy