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Making an ellipse. BY Alec Marshak & Kyle Harding. Supplies. Two pushpins A piece of computer paper A big piece of cardboard A 20cm long piece of string that is tied together to form a loop Lastly you need a pencil. Steps # 1-3.
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Making an ellipse BY Alec Marshak & Kyle Harding
Supplies • Two pushpins • A piece of computer paper • A big piece of cardboard • A 20cm long piece of string that is tied together to form a loop • Lastly you need a pencil
Steps # 1-3 • First fold the paper in half like a hot dog then open it and place it on the cardboard • Now draw two dots that are two centimeters apart in the middle of the paper • Now label the left focus F1 and the right focus F2 (The Sun)
Steps #4-7 • Place the pushpins into the two dots. Make sure to have pushed the pushpins all the way into the cardboard • Now you will put the string around the pushpins and insert your pencil inside the string loop • Use it by drawing a circle while puling outward on the string with your pencil (make sure the string stays on the pins)
Steps 7-8 • Take out the pushpins • Now draw a straight line through the middle of the ellipse connecting the foci to the outside of the ellipse and label it the major axis • Lastly, hand the perfect ellipse to your Earth Science teacher and hope for the best Congratulations
Finding the Eccentricity • When finding the eccentricity of an ellipse, you use the equation e=d/l . e=eccentricity, d=distance between foci, and l=length of major axis. So the steps are… • Measure the distance between the foci.(cm) • Measure the length of the major axis.(cm) • Divide the distance between the foci by the length of the major axis and the answer is the eccentricity.(cm to the nearest thousandth)
Our Ellipse • So using the steps from the last slide, we will figure out our ellipse’s eccentricity. The d=2 cm and the l= 10.8 cm.Next we divide 2cm by 10.8cm which equals .185.So our ellipse has an eccentricity of .185. • Now that we know our ellipse’s eccentricity we can compare it to another planet’s eccentricity. Compared to Mercury’s eccentricity our planet’s eccentricity is less eccentric. If our ellipse was a planet’s orbit, and it was compared to Mercury’s orbit our planet’s orbit would be less than and more circular.