0
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."
Wiki User
∙ 11y ago
Wiki User
∙ 11y agoA sundial measures the Sun's hour-angle, an angle on the celestial sphere that is equivalent to longitude. With the Sun on the meridian its hour-angle is zero, then the hour-angle increases, until 24 hours later it reaches 360 degrees and starts again.
The hour-angle is measured from the shadow of the sundial's central post.
Wiki User
∙ 11y agoNo, the sundial time will not always match your watch time because of the time zones. In one time zone only one line of longitude will allow the sundial to have the same time as the watch.
Comments: There's a lot more to this question than that. Apart from time zone and longitude effects (and "daylight saving" adjustments), there is a fundamental difference between sundial time and clock time.
Sundials work by using the Sun, but there are natural variations in the
"apparent solar time" that's measured in this way.
Our clocks use "mean solar time", which averages out the natural variations.
The two main causes of the natural variation are:
1) the fact that the Earth's orbit around the Sun is not a perfect circle.
2) the effect of the tilt of the Earth's axis.
These effects are dealt with by using the "Equation of Time".
The details are a bit complicated, but you can find out more on Wikipedia and other places. Just search for "Equation of Time".
Wiki User
∙ 13y agoNo. The time shown on a clock is a kind of long-term average of what a sundial would show. The accumulated difference can be about 15 minutes. More information here: http://en.wikipedia.org/wiki/Equation_of_time
Wiki User
∙ 10y agoThe shadow cast by the gnomon is longest in the Winter Solstice, whereas, it is shortest in the summer solstice. Hope this helped!
P.S. Are you from CHAC?
Wiki User
∙ 13y agoThere are 2 major problems; the bigger one is that it only works when sunlight is hitting it. It won't be of any use at night.
Add your answer:
Earn +20 pts
Where can one find live scorecards for the IPL cricket matches?
Match Time - Watch IPL matches LIVE at the site in the Related Links.
Could slaves tell time?
Yes. By looking at the sun, they could tell. Some of the Master's gardens for decor could had have a sundial for time.
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.
Name place where sundial is located in India?
Jantar Manters at Jaipur,Delhi and Indore.The biggest sundial in India is called 'samrat yantra'.It was built in 1728.
Where can you watch vault of bones adventure time?
You can watch Adventure Time on Cartoon Network.
What is used to measure time?
A clock, a watch, a sundial
What is a sundial and who was the first person to make it?
a sundial is a device that was used to tell time a long time ago. here is a vid that will tell you all about them: http://www.youtube.com/watch?v=tI0GqYJha1Q
What intrument to measure length of time?
its definitely not a clock...or a sundial...its a metronome!
Why does a gnomon on a sundial have to be 45 degrees?
It doesn't. The gnomon is supposed to match the latitude of the location where the sundial is placed. If the latitude is 30 degrees and the gnomon is 45 the entire sundial will have to be tilted to keep correct time. Another way to describe this is to say that the gnomon should be parallel to the Earth's axis.
Why is a sundial not a reliable way of telling the time?
You can't use a sundial in the night when its dark but you can tell the time using a sundial in daytime
WHAT IS THE importance of the sundial?
the importance of a sundial is for people to tell time.
What did George Washington use to tell the time?
He used a portable sundial.
Which kind of time does a sundial keep?
Not surprisingly, a sundial keeps solar time (and only while the sun is out...)
Which Four things used to measure time on earth are?
sundial, watch, clock, calendar, hourglass, egg timer, metronome, sun, moon........
What actors and actresses appeared in Time on the Sundial - 2010?
The cast of Time on the Sundial - 2010 includes: Michael Dacquisto as Director
Does the angle of a sundial change the time?
A sundial has to be positioned correctly in order to give you a good estimate of the time.
How can we use shadow to tell the time?
You can use a sundial, which is a device that uses the position of the sun's shadow to tell time. By placing a stick or pointer on the sundial, the shadow it casts can indicate the time based on markings on the sundial's face.
