Questions in the Science & Nature category.
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I'd like to build a shop light/tinker light out of cheap LED COBs, but I'm confused about how to size the driver. COBs have wattage, voltage and amperage ratings. To my understanding, to run 3 10w COBs, I would need a driver that puts out 30 watts. The voltage seems pretty straight forward, it's represented by a single number and the driver should be capable of delivering that. The amperage is where I get REALLY confused. [more inside]
After much lobbying, the council has planted some trees on the London housing estate where I live. Three years on, some are doing well, others less so. Some have been planted in grass-covered areas, and the grass has regrown up to the trunks. Could this be a major factor in why they're not growing very well? Is it likely to make much of a difference if I remove the grass around the base of the tree? Do I risk damaging the roots if I do?
I am trying to understand a statistical problem with resampling and variation, and I’m unsure of my terminology so it’s hard to search. I have a set of geographic areas with known populations, and I’d like to generate new areas with redistributions of those populations. I can assume that the population is evenly spread throughout the original areas, but this gives me numbers without any kind of confidence interval. What would I need to do to calculate variance or deviation for this problem? [more inside]
How do you preserve a dead beetle for long lasting ornamental value? [more inside]
Is there any scientific evidence that PMS/hormones make women unreliable/unstable? [more inside]
I lost/hid/misplaced an expensive and sentimental piece of jewelry several months ago. I really think I hid it somewhere in my house but I've searched and searched with no luck. Is hypnosis to remember what I did with it a real thing? Maybe I just lost it outside the house. I know it was in my purse at one point. [more inside]
What things should I bring along on a hike with some kids (age 9 & 12) who are curious about looking for cool rocks after a great demo in school? [more inside]
Is there a non-technical book that explains neural networks in sort of an introductory way for general readers? [more inside]
Please explain this ant (and other small insect) behavior I'm witnessing. [more inside]
After seeing the trailer for the latest King Kong movie, it got me thinking about why animals only get as big as they do. Is it because they evolve in an ecosystem and natural selection doesn't want you getting bigger than the food supply can managably feed? Is there a scientific principle that governs this that people have named? Is it a DNA thing? I guess I'm wondering what prevents gorillas from growing 100 feet tall. Could there ever be a mutation that allows this to happen? Thanks!
Dopamine floating around in your synapses will make you feel g<ood. But how? [more inside]
i want to put an inflatable pool in my small backyard. Then I want to fill it with water and lie on its surface on an inflatable chaise/raft thing. [more inside]
I am looking for research/articles/books on play in school-aged children. Ideally, about cooperative, imaginative play. I have found lots about play development from infancy to preschool age, but what I'm looking for is ages 5-13. Who has studied this period?
On January 28, at Schoolhouse Beach in Bodega Bay, California, I found scores and scores of these odd little things washed up on the beach. Do you know what they are? [more inside]
These are some pictures of the skull. The skull is from western Montana, which includes prairies. It was given to a friend of mine. It is about six to seven inches across and about 8-9 inches long. [more inside]
What's this flowering plant called? It's short, has thin grass-like leaves, and seems to pop up every spring in the middle of Alabama (Zone 8a).
Was thinking if I listen to my Ipod louder will it drain the battery quicker than if I listen to it at a quiter volume? However, I'm just using an Ipod as an example. I guess the same could be asked of any electrical item; say a TV set will it use more power if watched at a louder volume.
My four story apartment building is about 15 feet from a nearly identical four story apartment building to the south. I live on the third floor, and my apartment windows face south into the space between the buildings. Today at midday I can see the sun shining fully on the windows of the fourth floor apartment above mine, with the shadow from the other building starting just below their windows. How many days until it starts shining into my apartment and onto my cat? [more inside]
Can fish see through air? If you take a fish out of the water, can it resolve images and see as clearly as it presumably does in water? Or does its sight go all blurry the way mine does underwater?
Because the earth has an elliptical orbit, it travels at different speeds depending how far it is from the sun. Does this make some seasons longer than others? If not, why not? [more inside]