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Nuclear Fusion Makes Elements Form

You know that everything in the universe is made up of atoms, and that those atoms are all made up of smaller particles. In order to form different elements, we have to push those particles together in a process called nuclear fusion, something that requires extremely high temperatures and pressures, or break atoms apart in a process called nuclear fission. Look at the timeline below and notice when the first elements were formed from the Big Bang.
Notice that it took 300,000 years to finally form the first atoms. Up until that point, subatomic particles such as protons, electrons, and neutrons were the only matter flying around. When all those particles became fused, they formed the elements shown in the illustration. Looking at the periodic table of elements, “What do you notice about the three elements formed by the Big Bang?” Check your answer. As time went on, the universe cooled, creating the change in color from red to blue.  There wasn't enough pressure to fuse atoms any more, so hydrogen and helium began to form the first primitive galaxies.
As these primitive galaxies formed, there began to be massive groups of hydrogen and helium atoms. Eventually, as the pressure grew, there was enough pressure to fuse the hydrogen into helium, and our first stars were formed. Stars "burn" because they release large amounts of energy when hydrogen fuses to form helium and heavier elements such as carbon. The process of nuclear fusion starts when two hydrogen atoms collide and produce energy, two subatomic particles called neutrinos and positrons, and an atom of helium. In an average mass there is enough pressure to fuse larger atoms and form elements as heavy as iron. If the star is extremely massive, it will die in a violent explosion called a supernova. During a supernova, there is so much energy released that even elements heavier than iron are able to form by nuclear fusion. The elements formed on the inside of ancient, extremely massive stars and resulting supernovas are what make up our planet, including all life on it (that means you).

Enough reading! Lets use the Big Bang Time Machine to see all this happening. As you use the time machine, answer the questions below:

  • According to the Big Bang Time Machine, what elements were formed first and how long after the Big Bang were they formed?
  • According to the Big Bang Time Machine, how long after the Big Bang were the first heavier elements formed and where were they formed?
  • What do we call the process by which heavier elements are formed from two or more lighter elements coming together?
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Updated October 24, 2008 by: Glen Westbroek

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