So What s a Radian? 1.Balance Paper Plate on a Pin 2.Draw the Radius on the Plate 3.Use the index card to measure the radius 4.Transfer this measurement to the pie plate 5.Cut out the piece of pie formed by the radius
Coin Rulers Tape and Fold your Coin Rulers -Can you make 1 penny appear 1/2 as tall as another penny? -Can you make a penny and a nickel look the same size? -What is the relationship between the apparent size of a coin and its position along the coin ruler?
The Connection When an angle is small, the angle (measured in radians) is nearly the same as the ratio of the size of the object to the objects distance. For example, the Moon is 110 Moon- lengths away, so when we look at the Moon from Earth, it makes an angle of 1/110 of a radian from our eye.
Final Story Satellites, like Fermi, use this as a way to calculate the sizes of distant objects in space. If an object is many miles away and looks like a candle burning, it could be an entire city on fire. Well, if an object is billions of miles (or even light years) away and looks like a candle burning, it might be a supernova or an even bigger explosion called a gamma ray burst!
The Sun and the Moon Cut, tape and fold the Moon ruler. -How far away from the paper plate do you need to stand in order for it to appear to be the same size as the Moon? -How big does the Sun appear? -Explain a solar eclipse.
Janet Moore JanetMoore@gmail.com epo.sonoma.edu To download this presentation and a pdf of the booklet, visit: www.NASAJanet.com THANK YOU!