# Pi Day and Einstein's Birthday

## Pi Day | All About the Holidays

Pi Day | All About the Holidays. Pi is a very special ratio which calls for a very special holiday! Pi is the ratio of a circle's circumference (distance around the circle) to its diameter (distance across the circle).

PBS LearningMedia. K-4.

## Knights of Pi

Knights of Pi. Battle dragons and solve problems as you explore the kingdom. This interactive game focuses on geometric reasoning, specifically with regard to angles, triangles, and circles.

PBS LearningMedia. 5-8.

## Pizza Pi: Circumference and Area of a Circle

Pizza Pi: Circumference and Area of a Circle. In this interactive from APT, develop an understanding of circumference and the area of a circle and then practice these values with formulas. In the accompanying classroom activity, students review circumference and area of circles and then use the interactive. They use the formulas to solve area and circumference problems drawn from real-life contexts. To get the most from the activity, students should have some experience with the formulas for circumference and area of a circle.

PBS LearningMedia. 6-8.

## Calculating Pi With Darts | Physics Girl

Calculating Pi With Darts | Physics Girl. Pi can be calculated using a random sample of darts thrown at a square and circle target. The problem with this method lies in attempting to throw "randomly." We explored different ways to overcome our errors

PBS LearningMedia. 6-12.

## NOVA | Think Like Einstein

NOVA | Think Like Einstein. When Albert Einstein published his special theory of relativity in 1905, he laid out the foundation for the theoretical possibility of time travel. This interactive activity from the NOVA Web site presents the concepts Einstein used in special relativity, namely that the speed of light is constant for any observer, moving or not, and that because this is true, time can vary.

PBS LearningMedia. 6-12.

## Pi & The Fibonacci Sequence

Pi & The Fibonacci Sequence. Explore intriguing appearances of pi and the Fibonacci sequence outside of mathematics in this video from NOVA: The Great Math Mystery. Although well-known in mathematics, the numbers of the Fibonacci sequence are also frequently found in the natural world, such as in the number of petals on flowers and the number of spirals of a pinecone. Pi is commonly recognized as a number that relates a circle's circumference to its diameter but it also appears in many other phenomena. For example, pi is related to the probability that a dropped needle will cut a series of parallel lines; it also can be used to calculate the length of a meandering river.

PBS LearningMedia. 6-12.

## Einstein's Special Theory of Relativity

Einstein's Special Theory of Relativity. Einstein's special theory of relativity states that the same laws of physics hold true in all inertial reference frames and that the speed of light is the same for all observers, even those moving with respect to one another. In this video segment, adapted from NOVA, one of Einstein's thought experiments is re-created to reinforce one consequence of special relativity: that events that are simultaneous to one observer are not to an observer in a different reference frame that is moving with respect to the observer in the first reference frame.

PBS LearningMedia. 9-12.