Winter Solstice Activities for Kids: Measure the Shortest Day

The winter solstice is one of the few science events that children can check for themselves with a pencil, a ruler and a sunny spot. It happens around December 21 in the Northern Hemisphere, and it is the day with the fewest hours of daylight all year. This post gives you four activities that turn that fact into something children measure rather than just read.

What is actually happening

Earth spins once a day, but its axis is tilted about 23.4 degrees as it travels around the Sun. In December the Northern Hemisphere leans away from the Sun. The Sun’s path across the sky is low and short, so there are fewer hours of daylight, and sunlight arrives at a shallow angle that spreads the warmth out. At the solstice, the lean away is at its greatest.

Two points are worth getting right with children:

• Seasons come from the tilt, not from distance. Earth is actually closest to the Sun in early January. Many children (and adults) believe winter happens because Earth is farther away. Ask “if distance caused the seasons, what would happen in the Southern Hemisphere at the same time?” It makes a good puzzle.
• The shortest day is not the same as the earliest sunset. In many places at mid-latitudes the earliest sunset comes a week or two before the solstice, and the latest sunrise comes in early January. The day length is shortest at the solstice, but the morning and evening shift at slightly different rates.

Activity 1: Look up and graph the daylight

You need: a device to look up sunrise and sunset times (any weather or almanac site), paper, a ruler.

1. Choose four dates: around the first of September, October, November and December, or use the actual solstice dates if you want to compare June and December.
2. For each date, write the sunrise and sunset time for your town.
3. Work out the hours of daylight. (Subtract sunrise from sunset. Younger children can count whole hours on a clock face and “about” half hours.)
4. Draw a bar graph with the date along the bottom and hours of daylight up the side.

Ask: what pattern do you see? How much did the day shrink between October and December? What do you predict for January?

For a bigger comparison, look up two other cities: one much farther north and one much farther south. Where is the shortest day shortest? Children usually notice that the farther from the equator, the bigger the change.

Activity 2: A shadow stick at noon

A stick in the ground is the oldest solstice instrument there is.

You need: a straight stick or a ruler stood in a lump of clay on a flat, sunny spot, chalk or tape, a measuring tape, a clock.

1. Set the stick upright. A level check with a book or a plumb line (a string with a weight) helps.
2. Every 30 minutes from mid-morning to mid-afternoon, mark the tip of the shadow with chalk or tape and write the time.
3. Measure each shadow’s length. Which one is shortest? That moment is close to solar noon, when the Sun is highest, and it will not be exactly 12:00 on the clock.
4. Repeat on another day a few weeks later and compare the shortest shadow each time.

In the Northern Hemisphere, the noon shadow is longest at the winter solstice, because the Sun is as low as it ever gets. Safety rule, every time: never look at the Sun. Measure the shadow on the ground, not the Sun in the sky.

If you want to see the same idea on screen on a cloudy day, the Sun and shadow tool lets children move through the day and the year to see where the Sun is, how long a stick’s shadow is and how many hours of daylight any latitude gets.

Activity 3: A flashlight and a globe

You need: a globe (or a ball with a sticker marking your town), a flashlight, a dark room, a marker.

1. Tilt the globe about as far as it leans in real life and point the tilt toward a fixed spot in the room.
2. Shine the flashlight from the same distance at the globe’s middle, and keep the lamp still.
3. Move the globe “around the Sun” to four spots around the room, keeping its tilt pointing at the same spot. At the spot where your town leans away from the flashlight, the light hits it at a shallow angle and the lit patch is stretched out and dim. That is winter.
4. At the opposite spot, your town leans toward the light. That is summer.

Ask children to explain it to someone else using the globe. Explaining is the real check of understanding. The solar system tool shows the planets at true scale, which helps when children ask where the globe is “in space”.

Activity 4: Why the Southern Hemisphere is different

When it is winter in Canada, the United States and the United Kingdom, it is summer in Australia, New Zealand, South Africa and much of South America. The December solstice is the longest day of the year there, and their shortest day arrives around June 21. If you teach children in the Southern Hemisphere, simply flip the story: December is the long, bright month, and June is the one to measure.

For children who live in either hemisphere, this is a wonderful extension: look up December sunrise and sunset times for Sydney or Cape Town, and compare them with a northern city. The two graphs are almost mirror images.

And near the equator, day length changes only a little all year. Near the poles it swings to extremes: in winter the Sun may not rise at all for weeks. Ask children why a place on the equator would not have “seasons” that look like ours.

A simple plan for one week

• Day 1: Read about the tilt, then try the flashlight-and-globe model.
• Day 2: Look up daylight hours and begin the graph.
• Day 3: Set up the shadow stick on a sunny day.
• Day 4: Finish the graph and write “I notice… I wonder…” statements.
• Day 5: Explain the seasons to someone at home, and a Southern Hemisphere comparison.

If you would like the work done for you, the printable Shortest Day: Daylight Science pack gives children real sunrise and sunset data for cities to graph, a noon shadow comparison and a look at why Australia’s December is summer, with a teacher guide and answer key. You can find more seasonal science and math on the holidays and seasons calendar, and free printable pages on the worksheets page.

Frequently asked questions

Is the winter solstice really the shortest day?

It is the day with the fewest hours of daylight at mid-latitudes. Daylight then grows slowly, only seconds a day at first and a minute or two a day by late January, which is why the change is hard to notice until well into January.

What age is this suitable for?

Younger children (around Kindergarten to Grade 2) enjoy the globe model and the shadow stick. Grades 3 to 5 can calculate the hours of daylight and graph them. Older children can compare latitudes and explain why the angle of sunlight matters.

Do we need a sunny day?

For the shadow stick, yes, but you can do the graph and the globe model on any day. On cloudy days use the Sun and shadow tool instead.