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Why must sundials being used in the northern hemisphere be reversed in the southern hemisphere?
Wiki User
∙ 14y ago
During northern hemisphere summer the sun is in the northern sky in the Southern Hemisphere. Our sun in the northern hemisphere is almost always in the southern sky unless your south of the tropic of cancer so this is why you have to reverse the sundials if you move to the southern hemisphere.
Wiki User
∙ 14y ago
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Why are sundials inaccurate for measuring time?
The position of the shadow at a given time of day will vary slightly with the seasons. For example, if at 2:00 p.m. on 31 August the shadow is exactly on the 2, at 2:00 p.m. on 31 October it will be off a little. Of course for a sundial to be mostly correct most of the time, it has to be positioned according to where it is in the world. And of course, it will never take into account the fact that (in some countries) we switch to Daylight Saving Time part of the year. Here's an improved answer: Sundials are inaccurate for 3 reasons : 1) There's obviously the difficulty of getting an exact reading for "minutes" using are relatively crude device like a sundial. 2) Sundials measure "apparent solar time". Clocks use "mean solar time". "apparent solar time" varies a bit during the year because of the Earth's orbit and axial tilt. "Mean solar time" averages out these differences to give us a day of exactly 24 hours. So, a correction needs to be applied to get from the time the sundial shows to the time on a clock. 3) The other correction that's needed is for your longitude within your particular time zone. (Also "Daylight Saving" has to be allowed for, of course.) This adjustment is not really because the sundial is inaccurate, but it is needed to get to the standardised time shown by a clock.
Does your sundial match you watch time?
As the Sun moves across the sky (actually, it's the Earth turning), the shadows cast by objects move in the opposite direction. A sundial has a piece called a gnomen, and its shadow moves across marked sections for the hours. Because sundials were invented in the Northern Hemisphere, where the Sun appears in the southern part of the sky most of the year, the shadow moves "clockwise."
How did they tell time?
There were clocks and watches in the 1800s. Watches then were bulky compared to the ones today, and you would carry them in your pocket. They were powered by a metal spring, and you would have to wind them to keep them running. Clocks of the day generally had pendulums that would swing to keep the time. They also had to be wound about once a day. Some had a spring. Winding would coil up the spring, and the workings of the clock would be driven by the spring unwinding. Other clocks had a weight on a cord wrapped around a spindle. Winding would rais the weight, and as the weight went back down, the spindle turning drove the clock. There were also sundials that showed the time by the angle of a shadow, as the sun moved from east to west.
Why clockwise taken positive and anticlockwise taken negative?
This is because in the northern hemisphere, sundials would show clockwise, and most of the powerful countries are in the northern hemisphere therefore the majority of other countries adopted this.
What are the types of sundials?
The two types of sundials are altitude and azimuth sundials.
Why Sundials can't be used at night?
Sundials require sunlight.
Why do sundials need to be adjusted?
we have to adjust sundials to see the shadow and time
When did they use sundials?
There is no specific date stated as to when sundials were first used.
Who made the sundials?
Sundials are normally made of metal, however the materials may vary. Sundials were thought to be used in around 3500 BC.
Why do a clock's hand move to the right?
Well, clocks were originally designed to imitate sundials. The shadow of the Gnomon travels clockwise. At least in the Northern Hemispere, it does.
Why were sundials used?
Sundials were used to tell time, back without watches.
Where are sundials most comly found?
Where are most popular sundials are found?where where where can you answer me this thing only.......
What are the problems with using sundials?
Sundials do not work at night or on cloudy days- and they are not very portable.
Where were the first sundials used?
The sundials were first used back in the day around 1566bc1500bc-1300bc
Are there different types of sundials?
Sundials use the posidtion of the sun to cast a shadow on the dial. You can then read the number on where the shadow falls to get the time. As a result, no, there shouldn't be different types of sundials.
