Have you ever found yourself lost in the wilderness without a watch or a phone? If so, you may have wished you knew how to tell the time by the sun. It’s a valuable skill that can help you stay on track and avoid getting lost. In this article, we’ll teach you how to tell the time by the sun using a simple method that anyone can learn.
First, you need to find a flat, open area where you can see the sun clearly. Once you have found a suitable location, stand with your back to the sun and spread your arms out to the sides, like you’re making the letter “T”. Your left arm should be pointing to the east, and your right arm should be pointing to the west. Now, look at the shadow that your body is casting on the ground. The tip of your shadow will be pointing in the opposite direction of the sun, which means that it will be pointing towards the north. Once you know which direction is north, you can use the sun’s position in the sky to tell the time.
Determining the Time Using Solar Alignment
The time can be determined using the position of the sun by estimating the angle between the sun and the north-south axis. The time of day can be approximated using the following steps:
-
Position yourself so that the sun is directly in front of you.
-
Extend your arms so that they are perpendicular to the ground, with your palms facing the sky.
-
Turn your body so that your right arm points towards the sun.
-
The angle between your right arm and your body represents the time of day.
The following table provides the approximate time of day for different angles between the arm and the body:
| Angle | Time of Day |
|---|---|
| 6:00 AM | 30 degrees |
| 7:00 AM | 45 degrees |
| 8:00 AM | 60 degrees |
| 9:00 AM | 75 degrees |
| 10:00 AM | 90 degrees |
| 11:00 AM | 105 degrees |
| 12:00 PM | 120 degrees |
| 1:00 PM | 135 degrees |
| 2:00 PM | 150 degrees |
| 3:00 PM | 165 degrees |
| 4:00 PM | 180 degrees |
| 5:00 PM | 195 degrees |
| 6:00 PM | 210 degrees |
It is important to note that this method is only an approximation and can be affected by factors such as the time of year, the latitude of the observer, and the presence of obstacles blocking the sun.
Understanding the Sun’s Apparent Movement
The Sun’s apparent movement across the sky is caused by the Earth’s rotation on its axis. As the Earth spins on its axis, different parts of the Earth’s surface are exposed to the Sun’s rays. The part of the Earth that is facing the Sun experiences daylight, while the part that is facing away from the Sun experiences nighttime.
The Sun’s apparent movement across the sky is not constant. The Sun appears to move faster in the summer months than in the winter months. This is because the Earth’s axis is tilted away from the Sun in the winter months, which means that the Sun’s rays have to travel a longer distance to reach the Earth’s surface. In the summer months, the Earth’s axis is tilted towards the Sun, which means that the Sun’s rays have to travel a shorter distance to reach the Earth’s surface.
The Sun’s apparent movement across the sky can be used to tell the time. The following table shows the approximate time of day based on the Sun’s position in the sky:
| Sun’s Position | Approximate Time |
|---|---|
| Sunrise | 6:00 AM |
| Noon | 12:00 PM |
| Sunset | 6:00 PM |
Measuring Shadows for Time Estimation
Measuring the length of shadows can provide a rough approximation of the time of day, especially when clocks or other timekeeping devices are unavailable. The basic principle is that the sun’s rays reach the Earth at different angles throughout the day, causing the length of shadows to vary.
To estimate the time using shadows, follow these steps:
1. Choose a vertical object
Identify a vertical object, such as a pole, stick, or building, that casts a clearly defined shadow. Ensure that the object is not obstructed by any other objects.
2. Mark the shadow’s length
At a specific time, mark the length of the shadow on a flat surface or on the ground. You can use a stick, a pebble, or any other convenient object to mark the end of the shadow.
3. Note the sun’s position and time
Observe the sun’s position in the sky and note the corresponding time. The following table provides approximate time estimates based on the shadow’s length in relation to the object’s height:
| Shadow Length: Object Height Ratio | Approximate Time |
|---|---|
| Less than 1:1 | Morning (before noon) |
| 1:1 | Noon |
| More than 1:1 | Afternoon (after noon) |
It’s important to note that these time estimates are approximate and can vary slightly depending on the season, location, and time of year. Additionally, the shape of the object and the terrain can affect the accuracy of the estimation.
Measuring shadows for time estimation is a simple and practical technique that can provide a rough idea of the time, especially when other timekeeping methods are not available.
Using a Sundial to Tell Time
A sundial is an ancient instrument used to tell the time by the position of the sun. It consists of a flat disk with a pointer or gnomon fixed at an angle that is equal to the latitude of the location. As the sun moves across the sky, it casts a shadow on the disk, and the position of the shadow indicates the time.
How to Use a Sundial
To use a sundial, first make sure it is aligned with true north. This can be done by using a compass or by observing the position of the sun at noon, when it is at its highest point in the sky. Once the sundial is aligned, you can read the time by locating the shadow cast by the gnomon on the disk.
| Time of Day | Position of Shadow |
|---|---|
| Sunrise | Shadow falls on the east edge of the disk |
| Noon | Shadow falls directly below the gnomon |
| Sunset | Shadow falls on the west edge of the disk |
The exact time can be determined by interpolating between the hour lines marked on the disk. For example, if the shadow falls halfway between the 10 and 11 o’clock marks, the time is approximately 10:30.
Sundials are relatively accurate timekeepers, especially when used on clear days. However, they can be affected by factors such as the time of year, the location of the user, and the presence of obstacles that block the sunlight.
Compensating for Seasonal Variations
The Earth’s orbit around the Sun is not perfectly circular, but rather elliptical. This means that the distance between the Earth and the Sun varies throughout the year. As a result, the amount of time it takes for the Sun to move across the sky from sunrise to sunset also varies.
In order to compensate for these seasonal variations, you need to adjust the time you read from the Sun by a certain number of minutes. The amount of adjustment depends on the time of year and your latitude.
The table below shows the amount of adjustment you need to make for each month of the year, at different latitudes.
| Month | Latitude 0° | Latitude 30° | Latitude 60° |
|---|---|---|---|
| January | +10 minutes | +15 minutes | +20 minutes |
| February | +15 minutes | +20 minutes | +25 minutes |
| March | +20 minutes | +25 minutes | +30 minutes |
| April | +25 minutes | +30 minutes | +35 minutes |
| May | +30 minutes | +35 minutes | +40 minutes |
| June | +35 minutes | +40 minutes | +45 minutes |
| July | +40 minutes | +45 minutes | +50 minutes |
| August | +35 minutes | +40 minutes | +45 minutes |
| September | +30 minutes | +35 minutes | +40 minutes |
| October | +25 minutes | +30 minutes | +35 minutes |
| November | +20 minutes | +25 minutes | +30 minutes |
| December | +15 minutes | +20 minutes | +25 minutes |
Latitude and Longitude Considerations
The position of the sun in the sky varies depending on your latitude. At the equator, the sun is directly overhead at noon. As you move away from the equator, the sun will appear lower in the sky at noon.
Longitude also affects the time of day. The Earth is divided into 24 time zones, each of which is one hour apart. As you move from east to west, the time of day will get earlier. For example, if it is noon in New York City, it will be 9:00 AM in Los Angeles.
Calculating Sunrise and Sunset
The time of sunrise and sunset varies depending on your latitude, longitude, and the time of year. You can use a calculator or an app to find the times of sunrise and sunset for your specific location.
| Month | Sunrise | Sunset |
|---|---|---|
| January | 7:00 AM | 5:00 PM |
| February | 7:15 AM | 5:15 PM |
| March | 7:30 AM | 5:30 PM |
| April | 7:45 AM | 5:45 PM |
| May | 8:00 AM | 6:00 PM |
| June | 8:15 AM | 6:15 PM |
| July | 8:30 AM | 6:30 PM |
| August | 8:45 AM | 6:45 PM |
| September | 8:00 AM | 6:00 PM |
| October | 7:45 AM | 5:45 PM |
| November | 7:30 AM | 5:30 PM |
| December | 7:15 AM | 5:15 PM |
Before Beginning
Before learning to use the Sun as a clock, there are two key concepts you’ll need to know: the Earth’s rotation and its orbit around the Sun. The Earth rotates on its axis once every 24 hours, which makes the Sun appear to move across the sky from east to west. The Earth also orbits the Sun once every 365.25 days, which causes the Sun’s position in the sky to change throughout the year.
The Equinox and Solstice Effect
The Earth’s axis is tilted at an angle of 23.5 degrees. As the Earth orbits the Sun, this tilt causes different parts of the planet to receive more or less sunlight at different times of the year. The two extreme points of this tilt are called the summer solstice and the winter solstice. During the summer solstice, the Sun is at its highest point in the sky, and the days are longest. During the winter solstice, the Sun is at its lowest point in the sky, and the days are shortest.
The equinoxes occur twice a year, in March and September. During the equinoxes, the Sun crosses the equator, and the days and nights are of equal length. The time between the spring equinox (the one in March) and the summer solstice is called spring. The time between the summer solstice and the autumnal equinox is called summer. The time between the autumnal equinox and the winter solstice is called autumn. The time between the winter solstice and the spring equinox is called winter.
The table below shows the dates of the equinoxes and solstices for the year 2023:
| Date | |
|---|---|
| Spring equinox | March 20 |
| Summer solstice | June 21 |
| Autumnal equinox | September 23 |
| Winter solstice | December 22 |
Observing Daylight Saving Time
8. Adjusting for Daylight Saving Time
Daylight Saving Time (DST) is a practice of advancing the clock one hour during the summer months to make better use of daylight. The change occurs twice a year:
- Spring forward: Clocks are moved forward by one hour on the second Sunday of March.
- Fall back: Clocks are moved backward by one hour on the first Sunday of November.
Adjusting for DST when using the Sun to tell time:
When DST is in effect, the Sun will appear to rise and set one hour earlier than standard time. To compensate for this:
Before DST begins: Set your clock forward by one hour to match the earlier sunrise and sunset. This means you will see the Sun rise and set at approximately the same time as before DST.
When DST ends: Set your clock backward by one hour to align with the later sunrise and sunset. This will restore the time to its standard position.
Remember that the time adjustment applies to all timekeeping devices, including watches, clocks, and mobile phones, as well as schedules and transportation times.
| Before DST | During DST | After DST |
|---|---|---|
| Standard Time | Standard Time + 1 hour | Standard Time |
| Sunrise at 6:00 AM | Sunrise at 5:00 AM | Sunrise at 6:00 AM |
| Sunset at 6:00 PM | Sunset at 5:00 PM | Sunset at 6:00 PM |
Cross-Checking Time with Other Methods
Besides using the sun’s position, it’s advisable to cross-check the time with other methods for accuracy. Here are some additional ways to gauge the time:
9. Digital Devices: Smartphones, tablets, and watches often have built-in clocks that display the current time. While these devices rely on GPS or network synchronization for accuracy, they provide a convenient and reliable reference point.
10. Public Clocks: Public places such as train stations, bus stops, and town squares often have clocks that are regularly calibrated and maintained. These clocks can serve as a reliable source of accurate time.
11. Radio or Television Announcements: Many radio and television broadcasts include regular time announcements or display the time on the screen. These announcements can be used to check and adjust your timepiece.
12. Online Time Services: There are numerous websites and apps that provide real-time access to atomic or GPS-synchronized time. These services allow you to compare your timepiece to highly accurate sources.
| Method | Accuracy | Convenience | Relies on Technology |
|—|—|—|—|
| Shadow Clock | Medium | High | Not applicable |
| Timepiece | Low to high | Variable | Yes |
| Digital Devices | High | High | Yes |
| Public Clocks | Medium to high | Variable | Not applicable |
| Radio/TV Announcements | Medium | Medium | Yes |
| Online Time Services | High | High | Yes |
By using a combination of these methods, you can increase the accuracy of your timekeeping and ensure that you stay on track throughout the day.
Applying Your Time-Telling Techniques
Now that you understand the basic principles of time-telling by the sun, let’s put your techniques into practice:
1. Observe the sun’s position: Determine where the sun is in relation to the horizon. Is it low on the horizon, directly overhead, or somewhere in between?
2. Measure the angle of the sun: Use your hand, a stick, or any straight object to estimate the angle between the sun and the horizon. This angle is known as the sun’s altitude.
3. Estimate the time: Refer to the table below to estimate the time based on the sun’s altitude. Keep in mind that these are approximate times and may vary slightly depending on your location and the time of year.
| Sun’s Altitude | Approximate Time |
|---|---|
| 0-15 degrees | Sunrise or sunset |
| 15-30 degrees | 7-9 AM or 3-5 PM |
| 30-45 degrees | 10-12 AM or 12-2 PM |
| 45-60 degrees | 1-3 PM |
| 60-75 degrees | 4-6 PM |
4. Adjust for daylight saving time: If daylight saving time is in effect, add one hour to the estimated time.
5. Refine your estimate: With practice, you can become more accurate in your time-telling by observing the subtle changes in the sun’s position over time.
How to Tell the Time by the Sun
It’s possible to tell the time by the sun using a simple method called the solar clock. This method involves using a stick or other object to create a shadow and observing how the shadow moves throughout the day. By understanding the relationship between the sun’s position and the time of day, you can estimate the approximate time.
To create a solar clock, you will need the following materials:
- A stick or other object to create a shadow
- A flat surface to place the stick on
- A marker to mark the shadow’s position
Once you have gathered your materials, follow these steps:
- Place the stick vertically in the ground or on the flat surface.
- Mark the tip of the shadow on the ground or surface.
- Wait for about 15-30 minutes and mark the new position of the shadow.
- Repeat step 3 several times throughout the day.
As the day progresses, the shadow will move in a clockwise direction. By marking the positions of the shadow at regular intervals, you can create a solar clock that you can use to estimate the time.
People Also Ask About How to Tell the Time by the Sun
How accurate is telling the time by the sun?
The accuracy of telling the time by the sun depends on several factors, including the time of year, the latitude of your location, and the weather conditions. In general, it is most accurate around noon when the sun is at its highest point in the sky. However, it can be less accurate during the morning and evening hours or when there is cloud cover.
Can you tell the time by the sun at night?
No, it is not possible to tell the time by the sun at night because the sun is not visible below the horizon.
How was time told before clocks?
Before clocks, people used a variety of methods to tell the time, including sundials, water clocks, and hourglasses. These devices relied on the movement of the sun, water, or sand to measure the passage of time.
