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when we have different speed of cooling on two same type of refrigrators ,is there any effect on the consuptions of electricity electricity .By adjusting the lower speed can we reduce our electricity bills. —Preceding unsigned comment added by Khubab ( talk • contribs) 01:14, 29 December 2008 (UTC)
(Medical Advice request removed by JSBillings ) PitchBlack 03:38, 29 December 2008 (UTC)
If we cut the stem of the Neem tree, Leaves and branches comes at sideways. but this is not in the case of the stem of banana. If we cut it new one grows near the banana tree. what is the reason. —Preceding unsigned comment added by 203.129.203.164 ( talk) 05:54, 29 December 2008 (UTC)
First, I know this is the science desk, and maybe this is more of a miscellaneous question, but science and logic are connected so... Is there a name for the following logical fallacy: "The earth is lucky, because it is in the perfect green zone, not too far and not too close to the sun, etc." The same mislogic is shown when a person says "you are lucky because some other sperm could have reached the egg and you would never have existed if that had happened." Is this a named logical fallacy? One thing, I am not here to discuss whether either example is a fallacy or not. You are not going to convince me either is not and I'm not interested in that debate. Thank you.-- 68.237.248.155 ( talk) 06:46, 29 December 2008 (UTC)
Try here List of cognitive biases. I think it is probably more of a False analogy - usually these "you're lucky" are used to try compare apples and oranges. 194.221.133.226 ( talk) 10:43, 29 December 2008 (UTC)
I'll let the wind blow out the light
'Cause it gets more painful every time I die.— Children of Bodom
In people who have had multiple near-death experiences, are the subsequent ones more likely to be strongly negative than the first one? Neon Merlin 13:31, 29 December 2008 (UTC)
What are the chances that 2 brother's-in-law that are married to twin sisters develop acromegaly with the same type of pituitary tumor at the same time? These men live in different cities. Could foul play be involved? —Preceding unsigned comment added by CAElick ( talk • contribs) 14:42, 29 December 2008 (UTC)
Are Antibiotics effective? —Preceding unsigned comment added by Shodson8 ( talk • contribs) 16:56, 29 December 2008 (UTC)
Samuel Johnson is attributed with saying to an aspiring writer, "Your manuscript is both good and original, but the part that is good is not original and the part that is original is not good." Is it likely that my genome is like that manuscript? Neon Merlin 19:17, 29 December 2008 (UTC)
Imagine you made two identical cups of coffee. Imagine you made them both at 2pm so that they started off at the same volume and temperature (say 300ml at 100C), and you added an amount of cold milk (say 30ml at 5C) to one of them at 2pm and the same amount of milk at the same temperature to the other at 2.10pm. At 2.20pm, I believe that the drink you added the milk to first would be warmer than the drink the milk was added to later (assuming that neither drink had yet reached room temperature). Is that correct? —Preceding unsigned comment added by Milk Please ( talk • contribs) 20:18, 29 December 2008 (UTC)
clear;close all;
room_ambient_temp = 25;
tau_nlc = 60; % Time constant (Seconds) for the cooling
r_nlc = 1/tau_nlc; % constant for Newton's Law of Cooling in the form dT/dt = -r(T-Tamb)
% Initial coffee and milk parameters
coffee_volume = 300; % mL
coffee_temp0 = 100; % degrees C
milk_volume = 30; % mL
milk_temp0 = 5; % degrees C
% Initialize the coffee and milk parameters
coffee1_temp(1) = (coffee_temp0*coffee_volume + milk_temp0*milk_volume)/(coffee_volume+milk_volume)
coffee2_temp(1) = coffee_temp0;
%%Loop over time, measured after 2:00 PM, in seconds
for t = 1:60*30
coffee1_temp(t+1) = coffee1_temp(t) - r_nlc*(coffee1_temp(t)-room_ambient_temp);
coffee2_temp(t+1) = coffee2_temp(t) - r_nlc*(coffee2_temp(t)-room_ambient_temp);
% At time 2:10, add milk to Coffee #2
if (t == 60*10)
coffee2_temp(t+1) = (coffee2_temp(t)*coffee_volume + milk_temp0*milk_volume)/(coffee_volume+milk_volume)
end
end
%% Plotting, including time-stamped x-axis
time_labels = datenum(2008, 12, 29, 14, 0, 0) + 1/(24*60*60)*0:60*30];
plot(time_labels,coffee1_temp, 'r'); hold on;
plot(time_labels,coffee2_temp, 'b');
datetick('x', 16);
xlim([datenum(2008, 12, 29, 14, 0, 0), datenum(2008, 12, 29, 14, 20, 0)]);
legend('Coffee 1 - Milk Added at 2:00', 'Coffee 2 - Milk Added at 2:10');
xlabel('Time');
ylabel('Temperature (Celsius)');
title(['Hot Coffee Simulation with \tau = ' , num2str(tau_nlc) , ' sec']);
I obtained this temperature curve set when I set the time-constant of cooling to 1000 seconds (just over 15 minutes). Nimur ( talk) 21:53, 29 December 2008 (UTC)
Incidentally, I had to force myself to not use the heading "Hot Coffee", but I see that Nimur couldn't resist! :) Milk Please ( talk) 11:17, 31 December 2008 (UTC)
My batteries for my Nikon D1 are relatively new (a few months old), and have always given me trouble. They randomly stop working altogether after sitting overnight, and the battery meter often shows no sign of a low battery. To investigate, I ran the following experiment, and I would appreciate analysis. Please note that the experiment for battery #2 has not been completed yet, and please also note that the time intervals between tests is not regular. Thanks in advance for your help!
Experiment: Test battery's voltage at intervals starting from when it first comes off the charger and ending when it no longer powers the Nikon D1 camera.
Voltage tests are performed immediately after each camera test. Batteries are stored outside of camera in between tests.
BATTERY 1 (Powermart DNK004, rated 7.2 V)
2008-12-23 18:53 EST - 8.63 V, powers camera. (straight off of charger from normal Charge cycle)
2008-12-23 21:18 EST - 8.43 V, powers camera.
2008-12-24 00:04 EST - 8.36 V, powers camera.
2008-12-24 11:31 EST - 8.26 V, powers camera.
2008-12-24 20:17 EST - 8.21 V, powers camera.
2008-12-24 22:47 EST - 8.20 V, powers camera.
2008-12-25 01:09 EST - 8.18 V, powers camera.
(Experimental procedure change: Battery 1 is kept in D1 camera with power turned off instead of disconnected from camera.)
2008-12-25 10:39 EST - 8.14 V, powers camera.
2008-12-25 21:56 EST - 8.10 V, powers camera.
2008-12-26 12:09 EST - 8.06 V, powers camera.
2008-12-27 01:45 EST - 8.03 V, powers camera.
2008-12-27 13:35 EST - 8.00 V, powers camera.
2008-12-29 15:08 EST - 2.97 V, fails to power camera.
BATTERY 2 (Powermart DNK004, rated 7.2 V)
2008-12-23 14:41 EST - 8.57 V, powers camera. (straight off of charger from overnight Refresh cycle)
2008-12-23 15:15 EST - 8.46 V, powers camera.
2008-12-23 15:44 EST - 8.41 V, powers camera.
2008-12-23 16:13 EST - 8.38 V, powers camera.
2008-12-23 17:47 EST - 8.31 V, powers camera.
2008-12-23 18:52 EST - 8.28 V, powers camera.
2008-12-23 21:19 EST - 8.24 V, powers camera.
2008-12-24 00:05 EST - 8.21 V, powers camera.
2008-12-24 11:32 EST - 8.15 V, powers camera.
2008-12-24 20:17 EST - 8.11 V, powers camera.
2008-12-24 22:48 EST - 8.10 V, powers camera.
2008-12-25 01:09 EST - 8.09 V, powers camera.
2008-12-25 10:41 EST - 8.06 V, powers camera.
2008-12-25 21:57 EST - 8.04 V, powers camera.
2008-12-26 12:09 EST - 8.01 V, powers camera.
2008-12-27 01:45 EST - 7.99 V, powers camera.
2008-12-27 13:36 EST - 7.98 V, powers camera.
2008-12-29 15:09 EST - 7.93 V, powers camera.
Steevven1 (
Talk) (
Contribs) (
Gallery)
20:36, 29 December 2008 (UTC)
Your results for battery 1 are surprising. If the battery is not under load, why would it drop from 8.00 volts on 12-27 to 2.97 volts on 12-29. Was here some load on the battery in the meantime? Otherwise I would call it a "dud." For battery 2, you did not provide a report of a voltage at which it did not operate the camera ok. More and better characterized data is needed. Edison ( talk) 04:39, 30 December 2008 (UTC)
Hello. I read the binoculars article and wondered: What is the optimal eyepiece diameter for 7×50 binoculars so that I am not seeing two small dots and too much environment outside the binoculars? Thanks in advance. Have a happy new year. -- Mayfare ( talk) 20:53, 29 December 2008 (UTC)
When you look at the eyepieces closely, the eyepieces should not be so small that they are two small dots. Matching the dark-adapted iris - that leads me to an idea. -- Mayfare ( talk) 17:34, 30 December 2008 (UTC)
The holes in which the light exits is called the exit pupil. It is calculated by dividing the lens diameter by the magnification [3]. So, your binoculars' exit pupils should be about 7 mm. However, the optimum size for an exit pupil should be around 5 mm, depending on what you're viewing. It doesn't have much to do with the eyepiece diameter, because adjusting it would affect the madnification of the binoculars. Actually, that's the telescope formula, but maybe try searching the website for more info. I'm thinking either they put rings in the eyepiece, or the prism affects it, or you're just underestimating what the exit pupil actually is. Either way, hope this helps. Thanks. ~ A H 1( T C U) 23:33, 31 December 2008 (UTC)
Really cool invertabrae. http://www.flickr.com/photos/pokerchampdaniel/3136421527/
Science desk | ||
---|---|---|
< December 28 | << Nov | December | Jan >> | December 30 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
when we have different speed of cooling on two same type of refrigrators ,is there any effect on the consuptions of electricity electricity .By adjusting the lower speed can we reduce our electricity bills. —Preceding unsigned comment added by Khubab ( talk • contribs) 01:14, 29 December 2008 (UTC)
(Medical Advice request removed by JSBillings ) PitchBlack 03:38, 29 December 2008 (UTC)
If we cut the stem of the Neem tree, Leaves and branches comes at sideways. but this is not in the case of the stem of banana. If we cut it new one grows near the banana tree. what is the reason. —Preceding unsigned comment added by 203.129.203.164 ( talk) 05:54, 29 December 2008 (UTC)
First, I know this is the science desk, and maybe this is more of a miscellaneous question, but science and logic are connected so... Is there a name for the following logical fallacy: "The earth is lucky, because it is in the perfect green zone, not too far and not too close to the sun, etc." The same mislogic is shown when a person says "you are lucky because some other sperm could have reached the egg and you would never have existed if that had happened." Is this a named logical fallacy? One thing, I am not here to discuss whether either example is a fallacy or not. You are not going to convince me either is not and I'm not interested in that debate. Thank you.-- 68.237.248.155 ( talk) 06:46, 29 December 2008 (UTC)
Try here List of cognitive biases. I think it is probably more of a False analogy - usually these "you're lucky" are used to try compare apples and oranges. 194.221.133.226 ( talk) 10:43, 29 December 2008 (UTC)
I'll let the wind blow out the light
'Cause it gets more painful every time I die.— Children of Bodom
In people who have had multiple near-death experiences, are the subsequent ones more likely to be strongly negative than the first one? Neon Merlin 13:31, 29 December 2008 (UTC)
What are the chances that 2 brother's-in-law that are married to twin sisters develop acromegaly with the same type of pituitary tumor at the same time? These men live in different cities. Could foul play be involved? —Preceding unsigned comment added by CAElick ( talk • contribs) 14:42, 29 December 2008 (UTC)
Are Antibiotics effective? —Preceding unsigned comment added by Shodson8 ( talk • contribs) 16:56, 29 December 2008 (UTC)
Samuel Johnson is attributed with saying to an aspiring writer, "Your manuscript is both good and original, but the part that is good is not original and the part that is original is not good." Is it likely that my genome is like that manuscript? Neon Merlin 19:17, 29 December 2008 (UTC)
Imagine you made two identical cups of coffee. Imagine you made them both at 2pm so that they started off at the same volume and temperature (say 300ml at 100C), and you added an amount of cold milk (say 30ml at 5C) to one of them at 2pm and the same amount of milk at the same temperature to the other at 2.10pm. At 2.20pm, I believe that the drink you added the milk to first would be warmer than the drink the milk was added to later (assuming that neither drink had yet reached room temperature). Is that correct? —Preceding unsigned comment added by Milk Please ( talk • contribs) 20:18, 29 December 2008 (UTC)
clear;close all;
room_ambient_temp = 25;
tau_nlc = 60; % Time constant (Seconds) for the cooling
r_nlc = 1/tau_nlc; % constant for Newton's Law of Cooling in the form dT/dt = -r(T-Tamb)
% Initial coffee and milk parameters
coffee_volume = 300; % mL
coffee_temp0 = 100; % degrees C
milk_volume = 30; % mL
milk_temp0 = 5; % degrees C
% Initialize the coffee and milk parameters
coffee1_temp(1) = (coffee_temp0*coffee_volume + milk_temp0*milk_volume)/(coffee_volume+milk_volume)
coffee2_temp(1) = coffee_temp0;
%%Loop over time, measured after 2:00 PM, in seconds
for t = 1:60*30
coffee1_temp(t+1) = coffee1_temp(t) - r_nlc*(coffee1_temp(t)-room_ambient_temp);
coffee2_temp(t+1) = coffee2_temp(t) - r_nlc*(coffee2_temp(t)-room_ambient_temp);
% At time 2:10, add milk to Coffee #2
if (t == 60*10)
coffee2_temp(t+1) = (coffee2_temp(t)*coffee_volume + milk_temp0*milk_volume)/(coffee_volume+milk_volume)
end
end
%% Plotting, including time-stamped x-axis
time_labels = datenum(2008, 12, 29, 14, 0, 0) + 1/(24*60*60)*0:60*30];
plot(time_labels,coffee1_temp, 'r'); hold on;
plot(time_labels,coffee2_temp, 'b');
datetick('x', 16);
xlim([datenum(2008, 12, 29, 14, 0, 0), datenum(2008, 12, 29, 14, 20, 0)]);
legend('Coffee 1 - Milk Added at 2:00', 'Coffee 2 - Milk Added at 2:10');
xlabel('Time');
ylabel('Temperature (Celsius)');
title(['Hot Coffee Simulation with \tau = ' , num2str(tau_nlc) , ' sec']);
I obtained this temperature curve set when I set the time-constant of cooling to 1000 seconds (just over 15 minutes). Nimur ( talk) 21:53, 29 December 2008 (UTC)
Incidentally, I had to force myself to not use the heading "Hot Coffee", but I see that Nimur couldn't resist! :) Milk Please ( talk) 11:17, 31 December 2008 (UTC)
My batteries for my Nikon D1 are relatively new (a few months old), and have always given me trouble. They randomly stop working altogether after sitting overnight, and the battery meter often shows no sign of a low battery. To investigate, I ran the following experiment, and I would appreciate analysis. Please note that the experiment for battery #2 has not been completed yet, and please also note that the time intervals between tests is not regular. Thanks in advance for your help!
Experiment: Test battery's voltage at intervals starting from when it first comes off the charger and ending when it no longer powers the Nikon D1 camera.
Voltage tests are performed immediately after each camera test. Batteries are stored outside of camera in between tests.
BATTERY 1 (Powermart DNK004, rated 7.2 V)
2008-12-23 18:53 EST - 8.63 V, powers camera. (straight off of charger from normal Charge cycle)
2008-12-23 21:18 EST - 8.43 V, powers camera.
2008-12-24 00:04 EST - 8.36 V, powers camera.
2008-12-24 11:31 EST - 8.26 V, powers camera.
2008-12-24 20:17 EST - 8.21 V, powers camera.
2008-12-24 22:47 EST - 8.20 V, powers camera.
2008-12-25 01:09 EST - 8.18 V, powers camera.
(Experimental procedure change: Battery 1 is kept in D1 camera with power turned off instead of disconnected from camera.)
2008-12-25 10:39 EST - 8.14 V, powers camera.
2008-12-25 21:56 EST - 8.10 V, powers camera.
2008-12-26 12:09 EST - 8.06 V, powers camera.
2008-12-27 01:45 EST - 8.03 V, powers camera.
2008-12-27 13:35 EST - 8.00 V, powers camera.
2008-12-29 15:08 EST - 2.97 V, fails to power camera.
BATTERY 2 (Powermart DNK004, rated 7.2 V)
2008-12-23 14:41 EST - 8.57 V, powers camera. (straight off of charger from overnight Refresh cycle)
2008-12-23 15:15 EST - 8.46 V, powers camera.
2008-12-23 15:44 EST - 8.41 V, powers camera.
2008-12-23 16:13 EST - 8.38 V, powers camera.
2008-12-23 17:47 EST - 8.31 V, powers camera.
2008-12-23 18:52 EST - 8.28 V, powers camera.
2008-12-23 21:19 EST - 8.24 V, powers camera.
2008-12-24 00:05 EST - 8.21 V, powers camera.
2008-12-24 11:32 EST - 8.15 V, powers camera.
2008-12-24 20:17 EST - 8.11 V, powers camera.
2008-12-24 22:48 EST - 8.10 V, powers camera.
2008-12-25 01:09 EST - 8.09 V, powers camera.
2008-12-25 10:41 EST - 8.06 V, powers camera.
2008-12-25 21:57 EST - 8.04 V, powers camera.
2008-12-26 12:09 EST - 8.01 V, powers camera.
2008-12-27 01:45 EST - 7.99 V, powers camera.
2008-12-27 13:36 EST - 7.98 V, powers camera.
2008-12-29 15:09 EST - 7.93 V, powers camera.
Steevven1 (
Talk) (
Contribs) (
Gallery)
20:36, 29 December 2008 (UTC)
Your results for battery 1 are surprising. If the battery is not under load, why would it drop from 8.00 volts on 12-27 to 2.97 volts on 12-29. Was here some load on the battery in the meantime? Otherwise I would call it a "dud." For battery 2, you did not provide a report of a voltage at which it did not operate the camera ok. More and better characterized data is needed. Edison ( talk) 04:39, 30 December 2008 (UTC)
Hello. I read the binoculars article and wondered: What is the optimal eyepiece diameter for 7×50 binoculars so that I am not seeing two small dots and too much environment outside the binoculars? Thanks in advance. Have a happy new year. -- Mayfare ( talk) 20:53, 29 December 2008 (UTC)
When you look at the eyepieces closely, the eyepieces should not be so small that they are two small dots. Matching the dark-adapted iris - that leads me to an idea. -- Mayfare ( talk) 17:34, 30 December 2008 (UTC)
The holes in which the light exits is called the exit pupil. It is calculated by dividing the lens diameter by the magnification [3]. So, your binoculars' exit pupils should be about 7 mm. However, the optimum size for an exit pupil should be around 5 mm, depending on what you're viewing. It doesn't have much to do with the eyepiece diameter, because adjusting it would affect the madnification of the binoculars. Actually, that's the telescope formula, but maybe try searching the website for more info. I'm thinking either they put rings in the eyepiece, or the prism affects it, or you're just underestimating what the exit pupil actually is. Either way, hope this helps. Thanks. ~ A H 1( T C U) 23:33, 31 December 2008 (UTC)
Really cool invertabrae. http://www.flickr.com/photos/pokerchampdaniel/3136421527/