Sunrise Tracking Experiment: Find the Solstice Yourself

A sunrise tracking experiment gives a child something rare: a date they derived rather than looked up. Mark where on the horizon the Sun comes up each clear morning for six weeks and the pattern appears on its own. The marks creep along the horizon, slow down, stop, and reverse. That stopping point is the solstice, and the word says so: sol plus sistere, the Sun stands still. Then comes the fact that makes this worth doing properly. The shortest day and the latest sunrise are not the same date, and the gap between them is a month.

Key Takeaways

• From one fixed spot, you mark where the Sun rises against the horizon each clear morning for six to eight weeks, and plot it.
• The solstice shows up as a flattening in your data, not as a dramatic event, which is exactly what the word means.
• Best for ages 9 to 15, because the payoff is in reading a graph and noticing a subtlety.
• The thing that surprises everyone: at mid-northern latitudes the earliest sunset falls near 8 December and the latest sunrise near 5 January, with the shortest day in between.
• Use a stick’s shadow, not your eyes. Never look at the Sun, even low on the horizon.

What You’ll Need for the Sunrise Tracking Experiment

Item	How much	Where to get it	If you don’t have it
One fixed observing spot	1	A chalk cross on a patio, or a taped mark at a window	Stand with your heels against a specific doorstep every time
A vertical stick or dowel	1, about 50 cm	Garden centre, broom handle, bamboo cane	A pencil taped upright to a board
A board or paving slab to set the stick in	1	Home	Push the stick into lawn, marking its exact hole
Horizon sketch sheet	1 large sheet	Draw the skyline from your spot: roofs, trees, hills	A panoramic phone photo, printed
Chalk or removable markers	A handful	Hardware shop	Pebbles laid on the ground
Protractor and a long ruler	1 each	Stationery drawer	A phone compass app, which gives azimuth directly
Notebook or spreadsheet	1	Home	Phone notes, but a printed chart gets filled in more reliably

Time: prep 30 min, then 5 min on each clear morning for 6 to 8 weeks Cost: everything is probably in your kitchen or shed Mess level: low

Do the Experiment

Step 1 — Fix the observing spot permanently

Everything depends on standing in precisely the same place. Mark it: a chalk cross, a screw in a fence post, a strip of tape on a windowsill. Move 50 cm sideways and the Sun will appear to rise behind a different tree, injecting an error larger than the signal you are hunting.

Step 2 — Draw your horizon

From that spot, sketch the eastern skyline across a wide sheet of paper: the neighbour’s chimney, the tall tree, the hill. Accuracy of art does not matter; the landmarks are your scale. A printed panoramic photo taped to card works just as well and takes a minute.

Step 3 — Set up the shadow method

Push the stick in vertically at the observing spot. At sunrise, the stick throws a long shadow pointing directly away from the Sun, so you can read the Sun’s direction without ever looking at it. Chalk the shadow line on the ground and write the date beside it. This is both the safer method and the more precise one.

Step 4 — Record every clear morning, and the clock time too

Three things each morning: the chalk shadow line, a mark on the horizon sketch where the Sun’s upper edge first clears the skyline, and the clock time of that moment. Then get the official sunrise time for your town from the NOAA solar calculator so you have a reference column.

Step 5 — Keep going for at least six weeks, through a solstice if you can

The pattern needs time. Near an equinox the sunrise point shifts noticeably every single morning. Near a solstice it barely moves for a fortnight, which is the whole point but only visible across weeks. Mark the official solstice date on your chart in advance and keep observing past it.

Step 6 — Plot two graphs and compare them

Graph one: the sunrise direction, as an angle or a position along your horizon sketch, against date. Graph two: clock time of sunrise against date. Find the flattest part of graph one and the latest point of graph two. They will not be the same date, and explaining that gap is the best conversation this experiment produces.

What you should see: The sunrise point sliding along the horizon by up to half a degree per day near the equinoxes, slowing to almost nothing within ten days of the solstice, then reversing. On the clock-time graph, expect the latest sunrise to arrive a couple of weeks after the December solstice. Plan on losing half your mornings to cloud, and remember a daylight-saving change will put a one-hour step in your time data that is an artefact of clocks, not astronomy.

What’s Actually Going On

The Sun does not rise due east except at the equinoxes. Because Earth’s axis is tilted 23.4 degrees, the Sun’s apparent path through the sky shifts north and south over the year, and the point where it crosses the horizon shifts with it. At the June solstice it rises as far north of east as it ever will; at the December solstice as far south. In between it sweeps across, fastest at the equinoxes and slowest at the turning points, in the same way a pendulum moves fastest in the middle of its swing and pauses at the ends. That pause is the solstice.

Now the part that catches people out. If the shortest day is around 21 December, why is the latest sunrise in January? Because our clocks and the Sun keep different time. The US Naval Observatory’s own explainer gives the numbers for latitude 40 degrees north: earliest sunset around 8 December, latest sunrise around 5 January, and the least daylight on or about 21 December. It also notes the June equivalent: earliest sunrise around 14 June and latest sunset around 28 June, with the solstice near 21 June.

The cause is the equation of time, the running difference between clock time and true solar time. Earth’s orbit is elliptical and its axis is tilted, so the Sun’s apparent motion along the sky is not uniform. Through December and early January, solar time runs slow against the clock, delaying sunrise and sunset by up to about half a minute per day. Add that drift to the symmetric shortening and lengthening of the day caused by the tilt, and the two effects shift the extremes of sunrise and sunset apart while leaving the shortest day, the total daylight, where the tilt puts it.

Two measurement honesties. First, refraction: the atmosphere bends light, lifting the Sun’s image by roughly half a degree at the horizon, which is slightly more than the Sun’s own width. Sunrise as defined and published already accounts for this, and it means the Sun is geometrically still below the horizon when you first see it. Second, your horizon is not the ideal flat one used in published tables. A hill or a row of houses to your east will delay your observed sunrise by minutes, which is why your times will be consistently later than NOAA’s. Consistently, though, which means the shape of your curve is still right.

How to Explain It to Your Kid

Ages 5–8: the Sun’s door moves

Point at where the Sun came up and put a stone there. Do it again a week later and let them notice the stones are not in the same place. Tell them the Sun has a door in the sky that slides along slowly, and that twice a year it stops sliding and turns round. That is enough, and it is true.

Ages 9–12: fast in the middle, slow at the ends

Give them a pendulum, even a key on a string, and have them watch where it moves fastest and where it pauses. Then show them their own data: big daily shifts in the sunrise position in March and September, almost none in late June and late December. The word solstice means the Sun stands still, and they will have measured exactly that.

Ages 13+: the equation of time

This is a genuinely sophisticated topic and a motivated teenager can handle it. Give them the two contributions, orbital eccentricity and axial obliquity, and show how their sum produces the familiar lopsided curve with extremes near early November and mid-February. Then have them predict the latest-sunrise date for their own latitude and check it against published tables. An analemma photograph, the figure-of-eight the Sun traces if photographed at the same clock time all year, is the natural next project.

The question to ask: “If the shortest day of the year is in late December, why is the sunrise still getting later in the first week of January?”

Why Teaching This Early Pays Off

This is one of the few home experiments where a child can discover a genuine discrepancy. The naive model, that everything about the Sun should peak on the solstice, makes a clear prediction, and their own data breaks it. That is the structure of real science, and it is almost impossible to simulate with a worksheet.

The National Research Council’s Framework for K-12 Science Education names “analyzing and interpreting data” and “using mathematics and computational thinking” among its core practices, and this activity is unusually honest about both: the dataset has gaps, systematic offsets from a non-ideal horizon, and an artefact from daylight saving. Learning to keep a result while naming its errors is more valuable than any single fact about solstices.

There is also a reason to expect it to feel unproductive while it works. Deslauriers and colleagues found that learners consistently rate active methods as teaching them less, while measuring that they learn more. Six weeks of 6 a.m. chalk marks will feel pointless somewhere around week three. That feeling is not a signal to stop.

Before You Start: What Parents Should Know

Best age	9 and up. Younger children can place the stones, but reading a flattening curve is the payoff and it needs older eyes.
Supervision	Adult present at sunrise, mainly to enforce the no-looking rule and to keep the observing spot consistent.
Real hazards	Looking at the Sun. Even a low Sun can damage the retina, and it does so painlessly. Use the stick’s shadow to find its direction and glance at the horizon only briefly, never at the disc.
Don’t	Do not use binoculars, a telescope, sunglasses, exposed film or a smoked glass to look at the Sun. None of them are safe, and improvised filters are how people lose vision.

When It Doesn’t Work

• Half your mornings are clouded out. Normal. The pattern survives gaps because it is slow. Record “cloud” rather than skipping the row, so the gaps are visible in your chart.
• The times do not match the published sunrise. Expected, if you have hills, trees or buildings to the east. Your offset should be roughly constant. Note it as a correction rather than treating it as an error.
• A one-hour jump appears in the data. Daylight saving. Mark the changeover date on the chart and either convert everything to standard time or plot the two halves separately.
• The sunrise position barely moves at all. Either you are within two weeks of a solstice, which is the finding rather than a fault, or you are close to the equator, where the whole swing is smaller and the azimuth method matters far more than the clock method.
• Nobody can face getting up. Switch to sunset. The same physics applies in mirror image, the earliest sunset arrives before the solstice, and the evening is a far easier appointment to keep.

Take It Further

Build the horizon calendar. Once you know where the Sun rises at the solstice, drive a permanent stake on that sightline. Then sight along it on the same date next year. You have built the same device as Stonehenge, Chankillo in Peru and a dozen other ancient monuments, and the idea that a calendar can be made of two stones is a strong one.

Photograph an analemma. Take a photo from a fixed tripod position at exactly the same clock time, once a week for a year, and composite them. The Sun traces a figure of eight, and that shape is the equation of time made visible. It is a patient project and it is the single most impressive thing on this list. Pair this work with building a sundial that actually keeps time and the globe-and-lamp experiment on why seasons happen.

What to Watch For Over the Next 3 Months

• Week 4: They start predicting tomorrow’s mark before going outside, and get close. That is the shift from recording to modelling.
• Month 2: They notice the Sun coming through a different window at home, or hitting a different part of the kitchen wall, and connect it to the chart.
• Month 3: They ask about the midnight Sun, or whether the Sun ever rises due east. The second question has a precise answer and the first leads to latitude, which is the natural next step.

Frequently Asked Questions

Why isn’t the latest sunrise on the shortest day?

Because clock time and solar time drift apart. In December and January the Sun runs slow against the clock, pushing both sunrise and sunset later by up to half a minute a day. That shifts the extremes of sunrise and sunset away from the solstice, even though the total daylight is still shortest at the solstice.

Is it safe to look at the Sun at sunrise?

No. It looks dim and comfortable, but the near-infrared is still there and retinal damage is painless and permanent. Use the stick’s shadow for direction and look at the landmark, not the disc.

What if our eastern view is blocked by houses?

It still works. Your sunrise times will be later than published ones by a roughly constant amount, and the sunrise position against the rooftops is just as good a record as one against a clean horizon. A varied skyline actually makes the marks easier to place.

How long do we really need to observe?

Six weeks will show the slowing clearly if they straddle a solstice. Four weeks either side of a solstice is ideal. If you only have a fortnight, observe near an equinox instead, where the daily movement is fastest and most obvious.

Does this work near the equator?

Yes, with a change of emphasis. The sunrise point still swings through a total of about 47 degrees over the year, so the horizon method works well. Clock-time sunrise barely changes, though, so skip the time graph and concentrate on position.

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About the author

Ricky Flores is the founder of HiWave Makers and an electrical engineer with 15+ years of experience building consumer technology at Apple, Samsung, and Texas Instruments. He writes about how kids learn to build, think, and create in a tech-saturated world. Read more at hiwavemakers.com.

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Sources

1. US Naval Observatory, Astronomical Applications Department. “Sunrise and Sunset Times Near the Solstices.” https://aa.usno.navy.mil/faq/rs_solstices
2. US Naval Observatory, Astronomical Applications Department. “The Seasons and the Earth’s Orbit.” https://aa.usno.navy.mil/faq/seasons_orbit
3. US Naval Observatory. “Earth’s Seasons and Apsides.” https://aa.usno.navy.mil/data/Earth_Seasons
4. NOAA Global Monitoring Laboratory. “Solar Calculator.” https://gml.noaa.gov/grad/solcalc/
5. National Research Council. (2012). A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas. National Academies Press. https://doi.org/10.17226/13165
6. Deslauriers, L., McCarty, L. S., Miller, K., Callaghan, K., & Kestin, G. (2019). “Measuring actual learning versus feeling of learning in response to being actively engaged in the classroom.” PNAS, 116(39), 19251–19257. https://doi.org/10.1073/pnas.1821936116