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General Science / Re: Do two flu shots increase the immunity?

« on: 15/01/2013 00:04:45 »

Thank you for those answers. Always interesting how much more sense it makes to ask someone who might really know rather than just listen to the news.

The folks that throw around  the 60% number are not clear about that you most probably will not get the flu you have been vaccinated against, but that there is a 40% chance you might get infected by another strain. This is particularly confusing when they say that the flu shot was a good match this year.

I also heard that the protection rate is usually 60%. Why is it never much higher? Why would they not be able to match the mix of strains much better or worse some year?

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General Science / Do two flu shots increase the immunity?

« on: 13/01/2013 00:08:27 »

So they say that one flu shot offers about 60% protection. Does that mean that a second flu shot would increase the immunity? If yes, does it offer protection for 60% of the remaining 40% of the first vaccination and increase the total protection level to 84%?

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General Science / Re: Why is the salmon sparking in the microwave oven?

« on: 22/12/2012 22:52:23 »

Cool! So interesting. Thanks!

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General Science / Why is the salmon sparking in the microwave oven?

« on: 22/12/2012 18:47:52 »

I stumbled across an odd thing. At least it is odd to me.

I like to thaw small pieces of salmon in the microwave before putting them on my sandwich. I noticed that during the microwaving the darker areas of meat spark as if there were small pieces of aluminum foil present. Not just some small, barley visible sparks -  real nice sparks. And there is no aluminum foil present. Just the meat on a plastic lid.

What is going on?

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General Science / Re: Why do some people rest their heads on their hand/s?

« on: 26/10/2012 00:28:58 »

Like this:

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General Science / Why do some people rest their heads on their hand/s?

« on: 21/10/2012 00:22:10 »

When I think or listen intently I notice that I often end up with my chin resting in my hand. Am I doing this because I can think better or am I doing this to give my neck muscles a rest? Or can I think better if my neck muscles are less active? Does touching my chin help with anything? Other people do it too. Why?

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General Science / Re: Is there a "potential energy" radio?

« on: 29/07/2012 13:55:37 »

Your 10Kg weight suspended from some improvised attachment close to the ceiling is certainly more hazardous than using AA batteries.

I agree.
But the point was to find a reliable solution to power a radio in case batteries are not available and are desperately needed to hear learn what is going on with the help of a radio. Gravity can be found anywhere on this planet all the time and I was wondering if it could be used to power a radio. The discussion whether producing electricity this way is dangerous is besides the point since such an long-term emergency is inherently dangerous. Just having no shelter and water will kill many "civilized" people. Those who are smart and tough enough to have handled this will also be able to be careful about hanging something heavy in a tree.

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General Science / Re: Is there a "potential energy" radio?

« on: 28/07/2012 23:43:11 »

Well, I just checked and one source says that cranking the crank for 1 minute gives you about 4 minutes of radio play. I guess that makes sense considering the numbers. They are certainly not as efficient as I thought.

And yes, a mass suspended about 2 meters high is about a dangerous as a high bookshelf or a potted plant on a balcony. People who find themselves needing to use an emergency radio may be willing to take this crazy risk though.

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General Science / Re: Is there a "potential energy" radio?

« on: 28/07/2012 20:16:08 »

If I can use the crank on a hand-crank radio for about 30 seconds to get 15 minutes of emergency radio (not sure about those numbers) then it seems reasonable to me to assume that if I can haul up a 10kg mass 2 meters if would be enough energy to give me at least the same. The mass could even be the radio itself (with added water for extra mass) and the bottom of the rope would feature the ear plugs you use to listen.

wouldn't that be:
98N x 0.002m/s = 0.196W
?

Surprisingly enough that does not seem to be sufficient for a radio of 0.5W. Hmmm...
I wonder if I could even use a geared cranking mechanism to get the 10kg up the 2 meters with applying the same force. Cranking those radios for 30 seconds just does not seems that hard. This appears wrong. Is my math (and thinking) right?

The crank radios with batteries stink since the batteries that are recharged by the generator sooner or later don't hold a charge any longer. I like the capacitor concept. They may outlast batteries in their ability to hold a charge.

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General Science / Is there a "potential energy" radio?

« on: 28/07/2012 04:32:32 »

No, I am not talking about some miracle energy device, I am talking about pulling up a mass and letting it drop (slowly with the help of gears) to run a generator.

Has anyone here seen anything like this to operate, say, a small radio?

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General Science / Re: Does a multi-stranded wire have lower resistance?

« on: 29/06/2012 01:20:51 »

Yes, I am talking DC.

Where do the electrons flow in a bundle? I mean, if the sum of the resistance of the individual wires is higher than the resistance of the bundled up wires, there has to be some other path they take.

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General Science / Re: Has reality become boring?

« on: 28/06/2012 03:59:52 »

Should TV practice good "first responder" medicine?

TV CPR seems to be improving somewhat.  However, why is the first response to finding a "body" a scream, rather than the basics.

• Check Scene
• Check breathing, pulse, vitals, temperature, etc
• Notify someone to call Emergency (911 in the USA, 999 in UK)
• Start CPR if appears to be recent

Obviously in a good murder mystery one wants to limit disturbing the crime scene.  However, if I was a victim, I'd much rather someone try to save me rather than just waiting for someone else to show up and confirm death.

Based on personal experience, the first response to finding a dead body is rather shocking. Some people may respond with a scream although no one did on that sad day. TV folks chose to present those who are visually or acoustically remarkable somehow. Normal is boring. Reality TV is not real. It is heavily edited to increase viewer ratings. I agree that some documentaries are pretty decent and educational.

I still wonder about my initial post. Every time I begin teaching my robotics unit to a new batch of kids many are disappointed that they cannot create flying, shooting, killing machines. Most kids I encounter don't have the persistence to manage even basic programing  and prefer to return to their fantasy world where anything is possible. How can we convey to our youth that we will need their help if they are hiding somewhere where the real world's problems don't exist or are perceived as terribly uninteresting in comparison?

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General Science / Does a multi-stranded wire have lower resistance?

« on: 28/06/2012 03:38:29 »

Hello All:
Ohm's law says that a thinner wire has a higher electrical resistance than a thicker wire of the same material. Does one thick wire have less resistance than a bundle of thin wires of the same diameter? Does a wire with 100 thin wires have the same resistance than 100 individual wires of the same diameter that do not touch? Does a 1 meter wire containing 100 individual wires have the same resistance than 100 meters of the same thin wire? Does bundling them up change anything?

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General Science / Has reality become boring?

« on: 15/05/2012 00:47:06 »

I was thinking about this when I came here today. And then I read the thread about TV numbing the mind. One of the posters asked the question you can see in the subject line (and I liked it so much that I used it without permission  ^).

There are a lot of people who seem to be bored with what is possible in reality since they have become so used to what is possible in movies and video games. People all too often don't seem to be capable any more to separate fact from fiction. Or being interested in facts and currently unexplained facts. Why bother with reality if you can enjoy so much faster, higher, stronger, etc. in the fantasy world or when doing/watching extreme sports? Has this been like this for other generations before?  According to a TV show I saw, Star Wars has inspired some young people at the time to become engineers to create some of today's products. Does this still work? Can it still work when fiction is occasionally so outlandishly over the top? How do we interest young people in studying science and engineering when reality becomes boring to them?

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General Science / Re: Bucket of gross stuff

« on: 14/05/2012 00:14:03 »

No, but the DIY store might.
Some wallpaper pastes are based on the same stuff.
Add some food dye and you are well on the way.
The problem with stinky things is that they are often toxic. You can try onions.

Wallpaper paste, that is it! Cheap and readily available. Is there anything I should not mix with it as it will prevent it from getting gooey? I mean if I mix sour cream and onion and vinegar with it, will that mess it up? I assume few people have tried this, but chemists may be able to tell by just reading the ingredients.
Thanks!

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General Science / Re: Bucket of gross stuff

« on: 13/05/2012 14:38:59 »

The gunge that is widely used on television is an industrial powder thickener called Natrosol.

http://en.wikipedia.org/wiki/Gunge

Interesting. Thanks. I assume local grocery stores don't have it readily in stock.

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General Science / Re: Bucket of gross stuff

« on: 13/05/2012 14:23:54 »

Slimy is good. Some of the thickeners that go into jams and pie fillings might work well. If you include some edible chunks of marshmallow, or diced fruit, you can emphasize the grossness by sticking your hand into it and shoving some of it into your mouth.

What do you call the stuff that thickens jams and such? Pectin? Does one have to heat up the mix for it to work? I am talking about 240 liters of liquid and I would prefer to not have to have to boil all of it. I love the fruit idea. Even dried fruit is good. Left in the mix for a while it turns soft and squishy. Marshmallows are great too.

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General Science / Re: Bucket of gross stuff

« on: 13/05/2012 14:16:43 »

What are your goals?

The goal is to create buckets for of gross stuff for teenagers to reach in an retrieve certain items as fast as possible. I hope to compost the stuff afterwards. The mix can't be dangerous or so disgusting that someone might think it is dangerous. Maggots and discarded food are lovely but probably over the top for my purpose.

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General Science / How do I make a bucket of gross stuff?

« on: 13/05/2012 01:58:56 »

I am not sure if this is the right place to post this. It might be scientific enough though to qualify for this section.

I need to create 12 buckets full of gross stuff and would like your input on how to make them.

It needs to be about 4 gallons/16 liters per bucket. It should be harmless for the hands, non-toxic, not stain clothes, and be relatively cheap to make from common items one may find in a grocery store. In the end it can be a mix of things and the more revolting it looks or smells the better. I envision the majority of the contents of the bucket to be really slimy and thick. It should ooze of the hands. There can be chunks in there too.

Thank you for you "input".

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Technology / Re: How do I build a very fast model boat?

« on: 31/01/2012 20:41:41 »

Well, it has been a while but the race did not happen again until this last week and here are the two fastest boats. Mine (red) was second (grrr...) but it was close! Mass mattered a lot and the winning boat weighed in at 10g versus mine at 26g. Next time - lighter hulls, better sail shape. Both boats have the sail aft.

Just so you all know. I am sure you were anxiously waiting for the outcome of this thread. It helped a lot.