Even Bigger Than a T. Rex!

Comprehend the size of some gigantic dinosaurs.

  • Target Age:  3-6 
  • Learning Goals:  science, measurement, comparison
  • Related EpisodeEpisode 104: I'm a T-Rex! / Ned the Quadruped



Use a tape measure to mark off 3 different lengths on the ground for this activity: 40, 60, and 100 feet. Put a sports cone at the start and end of each of the lengths. (For older children, you may also wish to mark off each 10 feet on the field and put additional markers at each of these points. That way, they can practice counting by tens to the dinosaurs’ lengths. “10, 20, 30, 40…”)


  1. Ask your child to name some of the largest dinosaurs she knows about. Then, have your child watch a Dinosaur Train video clip (above) featuring of one of the longest dinosaurs ever, Argentinosaurus. Scientists believe it was at least 100 feet long. Explain that she is going to see for herself how REALLY large that is. But first she is going to compare her own length to a T. rex’s.
  2. Have your child lie down on the ground. Use a tape measure to find out your child’s length/height. Round this measurement to the nearest foot. Explain that Tyrannosaurus rex was about 40 feet long from the tip of his snout to the tip of his tail. Compare your child’s length with an adult T. rex’s.
  3. Attach a T. rex picture on the sports cone (or other marker) at the starting point marked off earlier, and stand next to it. Then, have your child take the second picture of the T. rex with a tape loop on it, and walk 40 feet to the end point, where the other cone is. Have your child attach the other T. rex sports cone at the other end.
  4. Use a stopwatch to see how long it takes your child to walk from one T. rex cone to the other. Write down this information on this chart. If you wish, you can ask your child to see how fast she can RUN this distance.
  5. Repeat Steps 3 and 4 for the other two dinosaurs species, Spinosaurus and Argentinosaurus (60 feet away, and 100 feet away, respectively).

Take it Further

To explore non-standard measurement, your child can measure the lengths of the various dinosaurs by walking heel-to-toe from one cone to another, and counting their steps. She might say, "A T. rex is 57 'Sarah steps.'" IMPORTANT: Make sure that your child doesn't accidentally put additional space in between her steps, as the measurement won't be accurate. As another activity, your child can divide the length of a large dinosaur by their length to see how many of their bodies put together would make a large dinosaur.

If doing this activity with more than one child, you can divide the last column of the chart ("Time") into more columns, one for each child running.

Dinosaur Train A to Z


Find more activities featuring your child’s favorite PBS KIDS character!