Performance Task : Sundial Time
Directions: Follow the instructions in the activity carefully.
Objectives: At the end of the activity, you will be able to make a sundial to cast a shadow allowing you to
gauge the time. You will demonstrate that the Earth is rotating, in relation to the sun, by showing how a
shadow moves throughout the day.
Materials:
Stiff piece of cardboard, file folder, tablet back, or other flat, durable surface to make marks on
Pencil or Chalk
Ruler or yardstick
Colored drinking straw, or other long, narrow object
Clay, tape, or other adhesive to adhere the object to the flat surface
Masking tape
Small scissors
Marker, pen, or pencil
Magnetic compass
Watch or clock
Timer, alarm, or stopwatch to alert you at one-hour intervals
Procedures: 1. Choose one of the long sides of your cardboard to be the bottom. Two inches from the
bottom, make a pencil mark in the center.
2. Use a pencil, small scissors, or other sharp object to make a small hole the same size, or slightly
smaller than, the straw.
3. Use the scissors to cut the straw: make three vertical, equal, halfinch cuts from the bottom of the
straw so that you can spread the sections out flat, for the straw to stand on. If you’re using a pencil or
other heavier object, skip this step.
4. Insert the top of the straw through the hole in the cardboard until just the cut sections remain on the
bottom of the cardboard.
5. Tape the cut sections securely to the bottom of the cardboard. If you’re using a pencil or other
heavier object, use clay on the top of the cardboard (instead of tape on the bottom) to hold your object
upright.
6. Now your straw should be standing upright when you place the cardboard on the ground or table.
7. Find a place where the sun shines all day and you can leave the sundial in the same position. Options
include your driveway, the sidewalk, your patio or other hard, flat surface.
8. Find North. Use a compass to find North. Position the cardboard so that the shadow of the straw
aligns with North on the compass. Use the masking tape to secure the cardboard to the ground or table.
9. Set your alarm for the next top of the hour (noon, 1:00, 2:00, etc.) When the alarm sounds, observe
where the straw’s shadow is on the cardboard. Align the ruler with the edge of the straw’s shadow and
make a pencil mark along the edge of the ruler.
10. Write the hour next to, on top of, or underneath, the mark. 11. Repeat the observation and notes at
each hour. If you started in the afternoon, come back to the sundial the next day in the morning hours
to complete the hour marks.
