Will watering plants with heated microwaved water kill the plant?

No. This question comes up repeatedly because of a nonsensical email that has been circulating since about 2010. The email features pictures of plants supposedly watered either with microwaved water or with water that has been heated on a stove top. Supposedly this little research gem was carried out by a student as a science fair project. And guess what! The microwave watered plants wither while the others flourish! One can come up with all sorts of possibilities explaining why differences could exist even if a legitimate attempt were made to carry out such an experiment properly. Was the soil the same in the two plants? Were they given equal amounts of water? Could they have been exposed to different lighting conditions? Was there some difference in the seeds? But before even asking such questions how about asking if pictures can lie? Absolutely! It isn’t very hard to take a series of two plants side by side and ensure that one thrives while the other dies. All you have to do is water one and not the other. Of course the possibility that this is the way the pictures were created does not prove the case.

Heating water in a microwave oven does nothing other than raise its temperature. Any talk about “the structure or energy of the water being compromised” is plain bunk. Water has no structure other than an attraction between the partially positively charged hydrogens in one molecule and the partially negatively charged oxygen atoms in adjacent ones. As far as altering the energy of the water, well, yes, that’s what heat is all about. Anytime anything is heated in any fashion its energy content is increased. The idea that microwaving water somehow changes its properties for the worse is plainly absurd.

But absurdly implausible arguments don’t prove that the pictures are faked either. What proves it is the good old standard of science, reproducibility. Or lack of. And we have done that. We have watered plants with microwaved water, kettle boiled water and stove top boiled water, feeling pretty sill about it, but we did it. The results? As expected, no difference. We aren’t posting any pictures because, after all, how would you know that they are not faked. So here is the choice. You can take our word that the experiment cannot be reproduced, accept that science tells us that microwaves do nothing to water other than heat it, or take at face value some pictures in a circulating email that purport to show an effect that has eluded scientists around the world but was discovered by a student pursuing a science fair project. The choice is yours.

5 responses to “Will watering plants with heated microwaved water kill the plant?”

  1. kiwi-ian says:

    There are 2 ways of looking at this experiment.

    It was a sincere study, but why only 2 plants?
    Why does the earth look different (less water? different temperatures? different watering? more ventilation?).
    Why cut the leaves off – they are the evidence and any leaf will help a p[lant get healthy again?
    We don’t actually see any sickness – we are told about it.
    Why leave gaping wounds that let infection in?

    Or this is FAKED.
    Look at the pictures for days 1 and 5, they are identical in every way (shadows, reflected light, stones, position etc), even the normal plant hasn’t changed at all, except that the microwaved water plant has had its leaves cut off. Or rather a photoshopped picture of the microwaved water plant!!

    What does this prove? Scissors are sharp.

  2. JT Jarvis says:

    Not that I believe the hoax story, however, this rebuttal article seems to miss a central point in its dismissal of the validity of such an experiment. The original experiment does not claim that it is the water *molecule* that undergoes change and harms the plant, but rather that microwaving conventional drinking “water” (which includes other stuff beyond straight H2O molecules) may lead to potentially unhealthy outputs (with water molecules obviously unchanged, but additional particles potentially undergoing change that results in a harmful substance substance being produced).

    Clearly, some substances (e.g. metals) when microwaved can produce gases that may or may not have health impacts to organics if consumed. In order for this science experiment to genuinely negate all negative health impacts for humans, many different kinds of compounds commonly found in food would need to be studied and results verified that microwaving these compounds did indeed not produce harmful substances.

    Heating and cooling pure water would of course not change the molecular structure of individual water molecules. But cooking food always changes the some of the chemical components of food, no matter how it’s cooked. Some of these changes due to microwave energy may lead to unhealthy outputs, which may or may not have significant health impacts over time. It’s a valid question to pose for the sake of human health, and to study it further as our food sources evolve.

    We must prove that microwaving *any and all* chemical compounds does not change the toxicity of those compounds (that is, we must falsify the harmfulness of microwave energy for all substances that are likely to find their way into our food supply). An experiment to prove that microwaving pure H2O doesn’t change the structure of the molecule is pointless and doesn’t negate the hoax experiments “findings” related to toxicity to plants and animals of microwaved substances. Inferring that microwaves have no impact on human health because they have no chemical effect on H2O molecules is clearly a problematic scientific method.

  3. kayla says:

    thats pretty cool to know

  4. Kristin Marshall says:

    I saw this email when it first started circulating, and was appalled at the concept. One set of results being used to make broad conclusions? What does THAT teach our kids? So reproduced the experiment with my kids. We took 4 plants, and watered them with tap water, boiled water, microwaved water, and grape pop. We constructed it to be double-blind and used a measuring cup to ensure even watering. I, the chief researched, was not responsible for watering them; the kids did that. And they did not know which plant was which (they were marked A, B, C, D). The result? The one watered with grape pop flourished. The next healthiest looking one was the microwaved water one. The boiled and tap water ones died. If we used the same scientific judgement as the science fair experimenter, we could conclude that the best fluid to support life is grape pop, and we should all commence drinking only that. But failing an adequate supply of grape pop, we could get by on microwaved water! Instead, I used this experiment as a tool for teaching my kids about what goes into making a scientific experiment legitimate, and why you need more than one sample to make any conclusions at all.

  5. Carlos chiu says:

    I believedit wouldn’t be any difference, but in the Science Fair they didthe experiment, same soil, same light, same amount of water, and after 10 days there was a difference. There was of course only three plants and the conclusion I get is that we need to make more experiments to validate that

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