Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Oxygenating Water
Name: Alayna
Status: student
Grade: 6-8
Location: AZ
Country: N/A
Date: November 2006

Question:
What is the best way to oxygenate distilled water? I need to do this for a science fair experiment, and I have found conflicting information on the Internet. Some say that shaking the water, or putting it in a blender will be sufficient, while others suggest using an oxygen pill such as the ones used to keep bait alive. However, I want to make sure I am only adding oxygen to the water, and not other chemicals. What do you suggest?



Replies:
If you do not want to add other stuff, then forget an oxygen pill. Shaking, blending, or using a fish tank bubbler will give you the oxygen you want.

Richard Barrans
Department of Physics and Astronomy
University of Wyoming


Alayna,

The only way that you can be sure to get only oxygen into your water is to have a very complex setup and pure oxygen from a gas cylinder. Since you are in 6-8th grade, this type of setup is not feasible. I would suggest an oxygen pill if you can find one, as that is something that you can measure and put into the water yourself. The pill should have a list of ingredients on it so that you can know what you are actually putting in the water. Putting the water in a blender will put air into the solution, which is mostly nitrogen and only about 20% oxygen, so the pill might get you more oxygen for your experiment. Write back to us and tell us more about what your experiment is about so that we can help you decipher what the best approach may be and what variables you might have to think about.

Matt Voss


Alayna,

The easiest way to add air to the water would be to use a air pump that one uses to get oxygen to fish in an aquarium.

Sincerely,

Bob Trach


Alayana-

- If you use a pill, it will include other chemicals. So you probably want to avoid that. Bubbling with air is chemically pure but might drag in some dirty dust unless you have a little air-filter on the pump intake tube. That inot hard to do. Bubbling with 100% oxygen from a compressed gas bottle is rather pure too. The only "chemical" that is almost pure is Hydrogen peroxide (H2O2). It looks and feels just like water, but it slowly breaks down into pure water (H2O) and Oxygen (O2). Hydrogen peroxide is real hard on living things, (tastes kind of ashy or tongue-biting too,) because it goes everywhere water goes while it is H2O2, and then tries to do bleaching actions as it breaks down there. So you probably need to use air or oxygen gas.

- How high is the oxygen level supposed to be?

A) about "100% of air-saturated" level (quite good enough for most living things). Since air is 20% oxygen, 100% air-saturated means oxygen builds up until it's partial pressure is 20% of 15psi, meaning about 3psi of just oxygen. (The rest of the 15psi is mostly nitrogen gas (N2). Bubbling with air does this. Blending does it faster.

B) 100% to 500%: Imagine the air in a blender was 100% oxygen instead of just 20%. That water would dissolve 5 times as much oxygen, up to 15psi partial pressure of O2 alone. However, blenders might not be real safe filled with pure oxygen. Because plastic and oil catch fire easier in oxygen, if there are sparks from the motor. Brisk bubbling in cool water is pretty safe, though. So bubbling oxygen gas through water is the usual way to do it. I think water in this oxygenation range won't always precipitate oxygen bubbles.

C) more than 500%. This can happen. The water will merely have a tendency to make little oxygen bubbles, just like soda makes CO2 bubbles. It will not last very long; it will go "flat" much quicker than a similar-sized glass of soda sitting out. Pills, or peroxide, or bubbling with 100% oxygen in a pressurized container, is required. I doubt you need this option.

- How long will the dissolved oxygen be needed to be kept high?

a) Are you doing this only once and then a quick one-shot experiment? (like measuring oxygen level with a chemical kit, or letting a fixed amount of oxygen get used up.) The blender does this.

b) Is it a long-running continuous-use experiment? ( like keeping an aquarium, or feeding bio-degradation, or other growth experiment, with used oxygen constantly being replaced) The bubbler does this.

- How long can you spend setting up your oxygen level?

1) sitting quietly in air (open container, filter-covering) might be good enough if the water is clean and you have a week to blow.

2) stirring does the same thing a bit faster. A swirling bowl of water would be saturated in less than a day.

2) bubbling does the same thing, but faster still. Also can be left on, to continually re-saturate the water. It's a little slow to get going, compared to a blender. Might take an hour at the start to make the water saturated. For the same flow if air, many small bubbles use more of the air and do the job faster than few large bubbles.

3) blender does the same thing, just fastest. Better than sitting a week; allows little time for dust to fall in or for slime to start growing.

4) Suppose there's some pill a that slowly decomposes generating oxygen bubbles. maybe it starts fast like a blender, but is not completely consumed immediately, so it also continues at a trickle like a bubbler. Good luck finding exactly this pill.

I would probably use (A)(2), bubbling with filtered air. It produces a widely recognized standard concentration of oxygen.

Measure your bubble rate in cm3/sec or some other numeric units, and tell the volume of your water bath, because together they tell any scientists that read your report how fast the bubbles can refresh the oxygen concentration in your water.

Of course, you forgot to tell me what your science fair experiment was about. So it is possible the blender is what you need instead.

Jim Swenson



Click here to return to the General Topics Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory