Slide1: Percy Julian Symposium
Oak Park River Forest High School 2007
By Evan Twichell Introduction: Introduction You have probably heard of a black hole before but you probably don’t know as much as you think you do.
A black hole is a celestial object that has such a huge gravitational pull that even light cannot escape it. History: History 1784-John Michell first proposed the idea of a black hole.
1915-Albert Einstein invented the theory of general relativity.
1930-Karl Schwarzschild invented a solution to describe the gravitational field of a spherical object. History (continued): History (continued) 1939-Robert Oppenhiemer and H. Snyder predicted that a huge star would eventually collapse into a black hole.
1967-Stephen Hawking and Roger Penrose proved mathematically that black holes are created naturally in the universe.
Formation and Characteristics: Formation and Characteristics A black hole is formed when a star at least the size of three solar masses collapses.
One solar mass is equal to or 1,989,100,000,000,000,000,000,000,000,000 kg.
A black hole has the same mass as a star. Characteristics (continued): Characteristics (continued) The event horizon of a black hole is the point of no return.
The singularity in the center has unknown physics. Accretion Disk and Plasma Jets: Accretion Disk and Plasma Jets An accretion disk is spinning gas and matter that a black attracts
Accretion disks convert matter to energy very efficiently
Viscosity in the disc redistributes angular momentum, causing material in the disc to spiral inward towards the singularity.
Plasma or Relativistic jet is plasma that is given of off by the black whole Accretion Disk and Plasma Jets: Accretion Disk and Plasma Jets Experiment : Experiment My experiment was to create a black hole model and test it with marbles and golf balls.
I made my own model of a black hole to perform the experiment.
The idea was to roll the marbles and balls into the model and time it. Hypothesis: Hypothesis I hypothesize that the bigger the object, the faster it will fall into the hole. Materials: Materials Metal rim
Stretchy fabric (nylon is good)
Embroidery thread (because it’s thicker)
Marbles (different sizes)
Assistant (optional but recommended)
Procedure: Procedure Step One: Make the model.
Step Two: Perform the experiment by rolling the balls in the model.
Step Three: Record the data. Data: Data Data: Data Conclusion : Conclusion My hypothesis was correct when I did my experiment.
But when I researched proven laws of gravity I found my hypothesis was technically wrong. Other sources: Other sources Einstein's theories state that gravity effects the amount of matter in an object not the amount of space it takes up.
Sources: Sources Blackhole. (n.d.). Astro Washington. Retrieved October/November 1, 2006, from
Black Holes. (n.d.). Wikipedia. Retrieved October/November 1, 2006, from http://www.juantrubin.com/encyclopedia/astronomy/blackhole
Cosmology. (n.d.). Berkeley. Retrieved November/December 1, 2006, from http://cosmology.berkeley.edu/Education/BHfaq
Deep space activity . (n.d.). PBS. Retrieved October/November 1, 2006, from