Nuclear Fusion

Multiple Choice

In nuclear fusion, smaller atoms are forced together to create larger atoms. Does this process release, absorb or maintain energy?

• Absorb energy
• Maintain energy
• Release energy

Stellar (Nuclear) Fusion

Nuclear Fusion = Process of energy generation. (Nuclear Energy)

Nuclei of lighter elements combine under extreme temperatures to transform into heavier elements and releasing TONS of energy!

Multiple Choice

the smallest particles of matter that still retain the characteristics of that element are called

• atoms
• nuclei
• dust 
• molecule

Birth of a star!

•  A star’s life begins when high temperatures and pressures within its core make the start of nuclear fusion possible.

• Gravitational forces pull the materials from a nebula inward.

• Decrease in space, causes an increase in molecular collisions (less place to roam)

• Increased molecular movement results in increased pressure and temperatures, too.

• Once protostar hits 10 million degrees, fusion of hydrogen begins!

• Fusion releases tons of energy, protostor ignites bright and A STAR TURNS ON (Birth).

Multiple Choice

Do all stars make energy through fusion?

• Yes
• No
• Just our sun
• Only large stars

Multiple Choice

What is a protostar?

• A star that has died

• A smaller than average star

• A big, blue star that is on the main sequence of the HR diagram

• A contracting mass of gas which represents an early stage in the formation of a star

Multiple Choice

Define nuclear fusion.

• Nuclear fusion – combining lighter atoms to make heavier ones – is what makes it possible.

• Nuclear fusion – splitting lighter atoms to make heavier ones – is what makes it possible.

• Nuclear fusion – combining heavier atoms to make lighter ones – is what makes it possible.

• Nuclear fusion – splitting heavier atoms to make lighter ones – is what makes it possible.

Multiple Choice

What is not produced when light elements undergo nuclear fusion?

• Heavier elements
• Energy 
• Lighter elements
• Light

Multiple Select

This process, called nuclear fusion, is the energy source of all __________.

There may be more than one answer for this questions.

• planets

• suns

• stars

• plants

Multiple Choice

In nuclear fusion, smaller atoms are forced together to create larger atoms. Does this process release, absorb or maintain energy?

• Absorb energy
• Maintain energy
• Release energy

Multiple Choice

When hydrogen is "fused" together on the Sun, what new element is created?

• Helium

• Carbon Dioxide

• Oxygen

• Light

Multiple Choice

When a young, developing star becomes hot enough and dense enough, the process of _______ begins.

• H --> He fusion

• He --> C fusion

• He --> C --> O fusion

• fission

Multiple Choice

Stars have loads of proton - proton chain reactions happening in its core. What charge do protons have?

• neutral - no charge

• positive

• negative

• neutrino

Multiple Choice

How is nuclear fusion different from nuclear fission?

• In fusion, the product is a larger atomic nucleus.
• Fission produces energy but fusion does not.
• Fusion produces energy but fission does not.
• In fission, the product is a larger atomic nucleus.

Multiple Choice

particles that are located in the nucleus of an atom and no charge

• proton
• neutron
• electron
• dust

Battle of the forces!

Gravity is constantly pushing the star inward. Nuclear fusion (energy release) generates the forces that push back! The result of this balance or imbalance of forces is what dictates the changes of a star (temperature, size, brightness, etc)

Multiple Choice

a dense positively charged sub atomic particle is called a 

• proton
• neutron
• electron
• plasma

Multiple Choice

Where does fusion occur naturally?

• Underwater
• All around us
• In the radioactive waste
• On the sun

Multiple Choice

Nuclear fusion is the reaction that generates energy in stars.

• True

• False

Multiple Choice

The sun is considered stable on the main sequence stage. Which statement below represents the MAJORITY of atoms combining together during the sun's fusion process?

• Helium and Hydrogen atoms

• Hydrogen atoms

• Hydrogen and Lithium atoms

• Hydrogen and Carbon atoms

Multiple Choice

Why does nuclear fusion require high pressures and temperatures?

• To provide enough energy to split the nucleus.

• The two nuclei are both negatively charged and repel each other.

• To lower the cost.

• To overcome the electrostatic repulsion of the nuclei.

Multiple Choice

When stars are in the main sequence, fusing hydrogen into helium, and are neither expanding nor contracting, they are said to be...

• dying

• in hydrostatic equilibrium

• white dwarfs

• red hypergiants

Fill in the Blank

Which element is used as the fuel in nuclear fusion reactions?

Why is main sequence the longest stage?

All stars begin with hydrogen and some helium. It isn't until all of the hydrogen has fused that the nuclear fusion will slow down. This process for all hydrogen to change, takes millions of years! During this time, the gravitational and nuclear forces are said to be in a balance = hydrostatic equilibrium.

Multiple Choice

In nuclear fusion, smaller atoms are forced together to create larger atoms. Does this process release, absorb or maintain energy?

• Absorb energy
• Maintain energy
• Release energy

Multiple Choice

From your lab, how will this star change based on the interaction of the gravitational forces and the nuclear forces?

• It is in equilibrium and will not change

• The gravitational forces are greater therefore the star's size will get smaller

• The gravitational forces are greater therefore the star's size will get larger

• The nuclear forces are greater therefore the star's size will get smaller

• The nuclear forces are greater therefore the star's size will get larger

Multiple Choice

The Sun core....

• The region of the sun where energy is produced.

• The region of the sun where solar flare happen.

• The sun spots are generated at core

• The carry particles of ligh

How will this star change?

The nuclear forces (gray arrows) are larger than the gravitational (black arrows) therefore the nuclear forces will push against the gravity and allow the size of the star to INCREASE.

Consider, with an increase in size, what will happen to the molecular pressures and temperatures of the star overtime.....

Multiple Choice

Two nuclei with low masses are combined to form one nucleus of larger mass is called what?

• Nuclear fission
• Nuclear fusion
• Nuclear half-life
• Half-life

Multiple Choice

Takes two small nuclei and combines them into a larger nucleus

• Fission

• Fusion

Multiple Choice

Where does nuclear fusion occur naturally?

• In nuclear bombs.

• In power stations.

• In stars.

Multiple Choice

Where does fusion occur?

• On the Sun and stars

• underwater

• all around us

• nuclear power plant

Multiple Choice

Which of the following describes nuclear fusion?

• The splitting of an atom into two or more atoms.

• The joining of two atoms to create a heavier atom and release energy.

Multiple Choice

When hydrogen is "fused" together on the Sun, what new element is created?

• Helium

• Carbon Dioxide

• Oxygen

• Light

Multiple Choice

Why does fusion only happen at very high temperatures?

• To overcome the repulsion of the positive nuclei.

• Because it only happens in stars.

• To increase the speed of the reaction.

Star Nucleosynthesis

Multiple Choice

What is the most common element in the universe? (Hint: Big Bang)

• Hydrogen

• Helium

• Lithium

• Neon

Multiple Choice

The heat generated through nuclear fusion in a star’s core exerts an outward force on the material around it. This would cause the star to expand, but it is balanced by another force acting upon the material in the star, which keeps it stable. What is the other force acting on the matter in the star?

• Gravity 

• Electrostatic attraction

• Pressure

• Electrostatic repulsion

Multiple Choice

What process is the source of energy in main sequence stars?

• Nuclear fission

• Nuclear fusion 

• Oxidation

Multiple Choice

Which element do main sequence stars primarily use for nuclear fusion?

• Oxygen

• Hydrogen

• Helium

• Iron

​Study these images for a minute to understand which element fuses into which element. 

Multiple Choice

Once the hydrogen in the core of a star runs out, what element does the star begin to fuse next?

• Carbon

• Boron

• Helium

• Lithium

Multiple Choice

Nuclear fusion only happens in the _______ of a star, where the _____ and ______ are high enough to allow nuclear fusion to occur.

• core

  temperature pressure

• outer layers

  pressure

  viscosity 

• outer layers 

  temperature

  pressure

• core

  temperature

  viscosity

​Nuclear fusion only happens in the CORE!

​Nuclear fusion takes place only at extremely high temperatures. That's because a great deal of energy is needed to overcome the force of repulsion between the positively charged nuclei. ... In the core, temperatures reach millions of degrees Kelvin.

​Study these images for a minute to understand which element fuses into which element. 

Multiple Choice

Once the hydrogen and the helium in the core of a star runs out, what element does the star begin to fuse next?

• Lithium 

• Carbon

• Iron

• Beryllium

Multiple Choice

Which two of the following elements are not formed in a main sequence star?

Carbon

Plutonium

Iron

Oxygen

Francium

• Carbon & Iron

• Oxygen & Plutonium

• Francium & Plutonium

• Plutonium & Iron

Multiple Choice

Which of the following elements can only be formed in a supernova?

• Helium 

• Uranium 

• Iron 

• Carbon