astronomy

What is Fusion?

What is Fusion?

Fusion is a reaction in which atomic nuclei combine to form a heavier nucleus with the release of energy.

What are the two things that are produced by nuclear fusion?

Heavier elements, and energy.

What kind of elements are created during fusion?

Elements up to Iron on the periodic table.

What is the heaviest element that can form through fusion in stars?

Iron

What is an atom?

The smallest unit of any element.

What is an Element?

An element is a specific type of atom, determined by the number of protons in its nucleus. The element of an atom determines its properties.

What particles make up an atom?

Protons - Positively charged, exist in the atom’s nucleus.

Neutrons - No charge, exist in the atom’s nucleus.

Electrons - Negatively charged, exist outside of the atom’s nucleus.

What determines what element a particular atom is?

The number of protons in its nucleus.

What determines the life cycles of stars?

The star’s mass.

What are the stages for stars with mass similar to the Sun?

(Protostar) > Main Sequence > Red Giant > Planetary Nebula > White Dwarf

What are the stages for stars with mass 5-20 times larger than the Sun?

(Protostar) > Blue Supergiant > Red Giant > Supernova > Neutron Star

What are the stages for stars with mass larger than 20 times the Sun?

(Protostar) > Blue Supergiant > Supernova > Black Hole

How are star mass and star life span related?

The more mass a star has, the shorter its lifespan will be.

What is a stellar nebula?

A cloud of gas and dust in space where stars are born.

What causes the gas and dust in a stellar nebula to collapse?

Gravity

What  process starts when a star is born?

Nuclear Fusion

What is the name for the process of gas in a stellar nebula becoming solid?

Condensation

What is the name of the process of smaller objects clumping together to form larger

objects in a stellar nebula?

Accretion

What happens to the rotation of the stellar nebula as it collapses?

The rotation speeds up.

What is radioactive decay?

The process by which an unstable atom turns into a different atom, accompanied by the release of radiation.

What is an isotope? Give several examples

Versions of the same element that have different numbers of neutrons. (e.g. Carbon-14 vs. Carbon-13 vs. Carbon-12. All of these have 6 protons because they are Carbon, but respectively have 8, 7, and 6 neutrons making up the rest of their mass)

What is a half life?

The amount of time it takes on average for half of a radioactive sample to decay.

What percent chance does one atom have of decaying during one half life?

50%

What percentage of a rock that begins as 100% U-235 will be lead-207 after 1 half life? After 2 half lifes? After 3 half lifes? (Assume all lead-207 is produced through uranium-235 decay)

50%, 75%, 87.5%

Why do different isotopes have different length half lifes?

Their differing masses give them different levels of stability.