Cheapest equipment to boil water at 60℃

  • #1
Summary:
How do we create a partial vacuum to boil water at about 60℃?
Water (any liquid) in a closed container boils when the vapor pressure of water (a property that depends on its temperature) equals the surrounding pressure. The vapor pressure of water at 60℃ is about ##1.99\times10^{4}## which is roughly 150 mm Hg.


This principle is so simple, and yet, it is rather difficult to demonstrate effectively at home (with cheap equipment the links to which I have posted to below). I have thought of doing this experiment in the following (perhaps simplistic) manner (see the Figure).
1632292733419.png

  1. Take a glass container and place a beaker of water at about 60℃ in it.
  2. Insert a thermometer and an electric vacuum pump in a lid and seal that lid to the container with some sealant like M-seal.
  3. Operate the pump to create partial vacuum.
I'd like the kids to see the water boil at about 60℃. My questions:

  1. I believe it should work, but are there any obvious flaws in my setup?
  2. Any tips to maximize the probability of success?

 

Answers and Replies

  • #2
Baluncore
Science Advisor
9,863
4,268
The "Vacuum Chamber Stainless Steel Kit" used for Degassing Urethane are listed on eBay.
They have a thick clear lid. Check they will operate at 70 deg C, and include a vacuum pump.
 
  • Like
Likes KedarMhaswade
  • #3
OmCheeto
Gold Member
2,191
2,644
Being the world's biggest cheapskate, I would recommend a hypodermic syringe. Here's the video that came up first when I googled:


These are called "flavor injectors" at the local grocery store I shop at. They cost about $5.
 
  • Like
Likes russ_watters, Drakkith, KedarMhaswade and 1 other person
  • #4
sophiecentaur
Science Advisor
Gold Member
2020 Award
26,585
5,590
Summary:: How do we create a partial vacuum to boil water at about 60℃?

Operate the pump to create partial vacuum.
Using a pump will cost money (if you don't already have one). To produce a low pressure you can do what the old Steam Engineers used to do. Boil some water in a closed container. Seal the container with a thermometer inside it. Gradually let air in until the temperature drops to 60C and then re-seal. The water will still be boiling if the pressure is around 0.2 Atmospheres. Job done.
Best to do this with a large container so the 60C temperature will be maintained for a reasonable while. If you add heat (low power is probably enough) the water will stay boiling and condensing on the outside of the container. This is just the same process as boiling water in a normal pan where the ambient pressure is 1 Atmosphere. A bit of skill would be needed to maintain the 60C and you need to avoid the temperature exceeding anywhere near 100C or the pressure in the container will be positive and potentially dangerous.
 
  • #5
Baluncore
Science Advisor
9,863
4,268
A bit of skill would be needed to maintain the 60C and you need to avoid the temperature exceeding anywhere near 100C or the pressure in the container will be positive and potentially dangerous.
The advantage of the "Urethane Degassing" containers is that the transparent lid rests in place on a silicon rubber seal. Positive pressure is therefore not possible.

You can implement a similar safe vacuum seal on another container. Make sure the cover is not screwed on. It must be held in place by the vacuum, so it will lift if subjected to any internal pressure.
 
  • #6
sophiecentaur
Science Advisor
Gold Member
2020 Award
26,585
5,590
The advantage of the "Urethane Degassing" containers is that the transparent lid rests in place on a silicon rubber seal. Positive pressure is therefore not possible.

You can implement a similar safe vacuum seal on another container. Make sure the cover is not screwed on. It must be held in place by the vacuum, so it will lift if subjected to any internal pressure.
That's interesting and shows that Engineers think about things when they design stuff!!. But my concern was with someone who seems to fancy doing an experiment starting from scratch. I was stating the obvious but no harm in that when there's an accident waiting to happen. The idea in my head was to have a rubber bung with a short taper, in a hole with a similar taper. A 90 degree taper and a massive area sounds even better.
 
  • #7
Being the world's biggest cheapskate, I would recommend a hypodermic syringe. Here's the video that came up first when I googled:


These are called "flavor injectors" at the local grocery store I shop at. They cost about $5.
This is pretty good. The only problem is that it's not easy to measure the temperature of the water as it boils in the syringe. As the demonstrator "claims" (of course, the claim may be true), the water actually cools down as it boils (owing to the latent heat that it loses as the steam extracts it from the water itself)! It would be cool ;-) if one could see that on a thermometer. So, I am enticed to try my own setup after I give the valve + syringe setup a try.
 
  • #8
sophiecentaur
Science Advisor
Gold Member
2020 Award
26,585
5,590
it's not easy to measure the temperature of the water as it boils in the syringe.
Standard trick is to use a heated water bath at 60C and keep the syringe under the water.
 
  • #9
OmCheeto
Gold Member
2,191
2,644
This is pretty good. The only problem is that it's not easy to measure the temperature of the water as it boils in the syringe. As the demonstrator "claims" (of course, the claim may be true), the water actually cools down as it boils (owing to the latent heat that it loses as the steam extracts it from the water itself)! It would be cool ;-) if one could see that on a thermometer. So, I am enticed to try my own setup after I give the valve + syringe setup a try.
That would be an interesting maths problem: Find out the conditions in a syringe that you would need to generate an easily noticeable temperature change.

My guess is that the syringe would have to be very large, or the amount of water would have to be very small.
I'm also guessing that air in the apparatus would mess things up a bit.
 
  • #10
1
2
I created a boiling display machine exactly as you have pictured. It worked fantastic. I used a vacuum desiccator, and a refrigeration grade vacuum pump.
The boiling temperature of the water is a function of the vacuum achieved by the pump. When I demonstrated it, the water would be at room temperature. When I started the pump, the water would start to boil. As there is no heat added to the vessel, and the liquid requires heat to boil, it would extract the heat from itself. As the water boils, its temperature drops. In my demonstration unit, it would take about 10 minutes of boiling before the temperature dropped to the freezing temperature, and Ice would form on the surface. it was and amazing demonstration for the principles of saturation temperature pressure relationships.
 
  • Like
Likes sophiecentaur and KedarMhaswade
  • #11
I created a boiling display machine exactly as you have pictured. It worked fantastic. I used a vacuum desiccator, and a refrigeration grade vacuum pump.
The boiling temperature of the water is a function of the vacuum achieved by the pump. When I demonstrated it, the water would be at room temperature. When I started the pump, the water would start to boil. As there is no heat added to the vessel, and the liquid requires heat to boil, it would extract the heat from itself. As the water boils, its temperature drops. In my demonstration unit, it would take about 10 minutes of boiling before the temperature dropped to the freezing temperature, and Ice would form on the surface. it was and amazing demonstration for the principles of saturation temperature pressure relationships.


That's cool! Could you add a picture?
 
  • #12
bob012345
Gold Member
1,030
321
Standard trick is to use a heated water bath at 60C and keep the syringe under the water.
Just the part up to the water level, right? The rest in ambient air for condensation?
 
  • #13
bob012345
Gold Member
1,030
321
That would be an interesting maths problem: Find out the conditions in a syringe that you would need to generate an easily noticeable temperature change.

My guess is that the syringe would have to be very large, or the amount of water would have to be very small.
I'm also guessing that air in the apparatus would mess things up a bit.
You can get big plastic syringes about an inch in diameter cheap at any pharmacy.
 
  • #14
bob012345
Gold Member
1,030
321
Is there a reason you want to boil water at 60 degrees or is than an arbitrary number less than 100 degrees?
 

Related Threads on Cheapest equipment to boil water at 60℃

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
5
Views
9K
  • Last Post
Replies
13
Views
1K
  • Last Post
Replies
1
Views
849
  • Last Post
Replies
6
Views
5K
Replies
1
Views
611
  • Last Post
Replies
13
Views
1K
  • Last Post
Replies
3
Views
740
  • Last Post
Replies
1
Views
5K
  • Last Post
Replies
12
Views
2K
Top