Why is water boiling at 96?

In summary: Try boiling the water in a sealed container to reduce the chances of this happening. 2) Maybe the thermometer is not calibrated. 3) Maybe the thermometer is not accurate. Try another thermometer.
  • #1
AHVincent
17
0
I have tested this with 3 thermometers, 2 Taylor digitals and a candy thermometer...

My water boils at 96 celcius and I'm in Pattaya Thailand with sea elevation of 8 meters...

Actually slow boil at 93-94 and very heavy boil at 97-97

I'm perplexed...!
 
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  • #2
Probably due to reduced atmospheric pressure.
 
  • #3
Thanks

But if I am at sea level?

Pressure is 1010 millibar, nothing spectacular...

Is it normal for boiling temperatures to vary as much as 5 Celsius at see level?
 
  • #4
Are you doing this in a lab with ventilation hoods?
 
  • #5
No ventilation hoods, just in large pot, 60 liters with 50 000 btu gaz burner, I also tried a 2 liter pot in case of limited heat distribution, same result.

Thermometers are Taylor instruments:

1479 5* Commercial Wireless Remote Thermometer

Plus a standard glass candy thermometer, they all agree on the readings.

I am boiling tap water, maybe I'll try distilled or ionized to see if it makes a difference?
 
  • #6
Try using a good lab grade thermometer with an immersion depth line. Insert the good thermometer up to the immersion depth line. If it has no line you must submerge the whole thing. Candy thermometers are not very precise and I think you've just proven that a barbeque thermometer cannot be used for precise work even though the digital readout gives you a temperature to a precision of tenths of a degree..
 
  • #7
Hi Chemistree,

I am getting an HM Digital pH meter tomorrow, so that will be the fourth instrument confirming my readings...could they ALL be defective simultaneously?

But I agree with you, I need something more accurate, however...I'm in Thailand...where can I find a proper thermometer online and what is the ball park I should expect to pay?
 
  • #8
I don't know how much a red liquid (don't use mercury) thermometer costs in Thailand. These guys might.

Don't measure boiling water with a pH meter... PLEASE!
 
  • #9
AHVincent said:
I am boiling tap water, maybe I'll try distilled or ionized to see if it makes a difference?
This was my first thought; I would expect minerals and such in the water to affect the boiling point. Although, I'm not sure which way it should affect it.
 
  • #10
chemisttree said:
I don't know how much a red liquid (don't use mercury) thermometer costs in Thailand.

Why not? For precision glass thermometers in laboratories mercury is still the gold standard.
The digital food thermometer has just ridiculously bad precision.
You need a calibrated precision thermometer e.g.
http://www.greisinger.de/index.php?task=2&wg=26
And should closely follow the instructions.

Further points to consider:
I would not use such a large volume. Is the vapour in equilibrium with the liquid (i.e. you should measure not in an open pot but in a closed system with only a small opening for pressure equilibration. ) ?
Purity of the water?
Even with a glass thermometer there are correction factors for temperature of the surrounding and the like.
 
  • #11
I have tried reducing the volume to 1 liter, the probe is fully submerged with the sensor not touching the steam. Will do a test with a closed container and ionized water later today or tomorrow and record the results.

All 3 thermometers record the exact same temperatures in unison...one of them is glass with red liquid.

If I can't figure this out I'll do a movie on youtube of the experiment, I'd really like to get to the bottom of this!
 
  • #12
Hurkyl said:
This was my first thought; I would expect minerals and such in the water to affect the boiling point. Although, I'm not sure which way it should affect it.

Up. It is called "boiling point elevation" for a reason.
 
  • #13
I think you just calibrated your thermometers...

Now try them in ice water...
 
  • #14
Ice water test is next with all 3
 
  • #15
Actually, something else I will do is try the thermometer in one of the local noodle soup shops pots in the street (I'm in Thailand ;) and see what boiling temperature I get with them!
 
  • #16
AHVincent said:
No ventilation hoods, just in large pot, 60 liters with 50 000 btu gaz burner, I also tried a 2 liter pot in case of limited heat distribution, same result.

Thermometers are Taylor instruments:

1479 5* Commercial Wireless Remote Thermometer

Plus a standard glass candy thermometer, they all agree on the readings.

I am boiling tap water, maybe I'll try distilled or ionized to see if it makes a difference?
There may be something wrong with your thermometer. Try another thermometer.

If you used a massive thermometer, then maybe you didn't wait for the thermometer to equilibrate. What type of thermometer did you use?


Okay. After this, one has to consider the more exotic explanations. Maybe the water is not boiling.

1) Maybe the water is effervescing.

The solubility of gases decreases with temperature. If the water had a lot of air dissolved in it, then the air would be driven out of the water forming bubbles.

If the water had just been taken out of a cold area, the water could have dissolved a lot of air. When you heated it, the air could have been driven out the air.

If this is effervescing, then the bubbles should soon stop.

2) Maybe the water is mixed with a more volatile liquid such as alcohol.

Also, the water may be mixed with a more volatile liquid such as alcohol. A water-alcohol mix would have a lower boiling temperature than neat water. If you keep boiling a water-alcohol mixture, the boiling temperature will rise as the alcohol is driven off.

3) Maybe the liquid isn't water at all !-)

No suggestions there.
 
  • #17
The only things I can think of that would lower the BP would be some azeotrope or if the work were being conducted in a lab under slightly negative pressure, thus my question about ventilation hoods.

If this work is being done indoors, open a door to the outside a small amount and see if you feel an inward draft of outside air. Alternatively, you could accurately measure the atmospheric pressure where the work is being conducted. The boiling point of water is affected by pressure so that a BP reading of 96C for water occurs at about .87 bar which is equivalent to an increase in elevation of about 3200 feet.
 
  • #18
DrDu said:
Why not? For precision glass thermometers in laboratories mercury is still the gold standard.
You shouldn't find mercury thermometers in a food grade manufacturing facility. The manufacturing facility I'm familiar with has specific instructions against having them on the property.

The digital food thermometer has just ridiculously bad precision.
You need a calibrated precision thermometer e.g.
http://www.greisinger.de/index.php?task=2&wg=26
And should closely follow the instructions.
Probably better to say it has ridiculously bad accuracy. It could indeed measure temperature with an acceptable precision but just not accurately.
 

1. Why does water boil at 96 degrees?

Water boils at 96 degrees because of its unique chemical and physical properties. At sea level, water boils at 100 degrees Celsius, but this temperature decreases at higher altitudes due to a decrease in atmospheric pressure. The lower boiling point at higher altitudes means that water can boil at a lower temperature, such as 96 degrees.

2. Is it possible for water to boil at a temperature other than 96 degrees?

Yes, it is possible for water to boil at a temperature other than 96 degrees. The boiling point of water is influenced by factors such as altitude, pressure, and impurities in the water. For example, water with salt or other substances dissolved in it will have a higher boiling point than pure water.

3. How does atmospheric pressure affect the boiling point of water?

As mentioned earlier, atmospheric pressure plays a significant role in the boiling point of water. The higher the atmospheric pressure, the higher the boiling point of water. This is because the increased pressure makes it more difficult for water molecules to escape into the air, resulting in a higher boiling point.

4. Why does water boil faster at higher altitudes?

Water boils faster at higher altitudes because the atmospheric pressure is lower. This lower pressure allows water molecules to escape more quickly, resulting in a lower boiling point. For example, water at the top of a mountain will boil faster than water at sea level because the atmospheric pressure is lower at higher altitudes.

5. Does water always boil at 96 degrees at higher altitudes?

No, water does not always boil at 96 degrees at higher altitudes. While 96 degrees is a common boiling point for water at high altitudes, factors such as air pressure and the purity of the water can cause the boiling point to vary. Additionally, the boiling point of water can also change depending on the specific location and altitude.

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