Science Forums 2

[CraigD]

Originally Posted by hallenrm

I wonder if the expermenter in the linked article implied that the water was boiled in a microwave oven every day, before it was used for watering (after cooling ofcourse) or whether microwaved water was stored for the period of the experiment (as is suggested in your procedure).

I would therefore suggest that experimenters should try both approaches.

It’s best, I think, to design the experiment to be most likely to produce the hypothesized effect (plants watered with water heated in a microwave oven water grow differently than plants watered with water heated on a stove), so the procedure should be to reheat and cool the water each day (both in a microwave, and on a stove).

This makes the experiment more difficult (that is, more effort-consuming) for Alice and Bob, and introduces the need for new checks, both to assure that both waters are at the same temperature when applied to the plants, and to assure that nobody knows which plant is receiving which kind of water until the experiment is complete.

Here’s a revised draft design:

1. A person (Alice) decants tapwater water into several identical containers.
2. Alice labels half of the containers with 1 random (drawn blind from a “hat”) 2 digit number (A), and half with another (B).
3. Alice label 2 identical pots with 2 random 2 digit numbers (C and D).
4. Alice notes on a single piece of paper which numbered pot will receive water from which numbered container, seals the paper in an envelope, and places it in a secure place (that Bob can’t see).
5. Another person (Bob) notes on a single piece of paper which numbered container (C or D) will be heated on a stove (S), and which will be heated on a microwave (M), seals the paper in an envelope, and places it in a secure place (that Alice can’t see).
6. Alice plants identical seeds in each pot.
7. Each day (including just after planting):
   1. Bob decants the water from the S container into a stove/microwave safe pot (eg: Correl “Visions” glassware), and covers it
   2. On a stove, Bob raises the water to a boil and boils it for 2 minutes
   3. Bob places places a thermometer inside the pot, places the pot in a refrigerator, and cools it to room temperature (22° C).
   4. Bob decants the water into the S container.
   5. Bob repeats steps 7.1-4 with the M containers, using a microwave oven in place of a stove
   6. Alice waters the plants in pot C and D with the corresponding water from containers A and B.
8. When the water is used up, Alice notes on a piece of paper the label number of the plant that appears healthiest, or notes that she can detect no difference.
9. If no difference is detected, the experiment is over, with a null result.
10. Alice and bob retrieve and compare their pieces of paper, and determine which of the 2 kinds of water was used to water the healthier and less healthy plant.

Note that, because Alice and Bob have more interaction in this design, so diligence must be excercised to assure that blindness is preserved, and neither Alice not Bob know which plant is receiving M water, and which is receiving S. Ideally, at least Bob should be skeptical of the hypothesized effect, so that he has no incentive to attempt to defeat the blinding measures, for example by placing a secret mark known by Alice on the containers.