Lab Practical Review Day 2 A. Earthquakes: Locating an Epicenter B. Astronomy: Constructing and Analyzing an elliptical orbit

Locating an Epicenter 1.) Using a seismogram, write down the arrival of the P and the S wave 2.) Find the S-P interval (subtract time difference between arrival times) – here it would be 00:04:00 – 4 minutes

3.) Mark this time interval on a scrap piece of paper using the y-axis in your ESRT pg. 10 4.) Slide this piece of paper over until the time interval fits exactly between the P and S waves on the chart. For example if the S-P interval was 05:25, the distance to the epicenter would be ~3,800 km

Draw the distance to the epicenter using your compass Ex: Your seismic station was in San Francisco, with a found distance of 2,800 km to epicenter. Mark set distance on map from station using your scrap Mark distance on scrap using map scale Draw circle!-put pencil in the closest opening to your mark!

Example of what a finished map looks like

Eccentricity Eccentricity defines how eccentric (stretched out) an orbit is and is defined by the equation e = d/L (pg. 1 ESRT) Eccentricity has values between 0-1 (NO UNITS) Values closer to 0= less eccentric. Values closer to 1= more eccentric.

Calculating Eccentricity After Drawing your Ellipse

Comparing your calculated eccentricity to known eccentricities of planets