Physical Science 6-4: Radioactivity & Energy from the Nucles

​Radioactivity & Energy from the Nucleus

Fill in the Blank

A kid applies a force of 60 N to a ball over 2.5 meters. How many joules of work did he do on the ball? 

Multiple Choice

An apple hangs in a tree. What type of energy is present?

• Kinetic Energy

• Potential Energy

Fill in the Blank

You do 120 joules of work in 36 seconds. How many watts of power have you generated? Round to two Decimal Places!

.

Multiple Choice

When you touch a hot iron, you may burn your hand. What kind of heat transfer is this?

• Convection

• Conduction

• Radiation

Fill in the Blank

Mr. Kierny throws a baseball at 15 m/s. The ball has a mass of .15 kg. What is the kinetic energy of the baseball? Round to 2 Decimal Places

.

Multiple Select

Convection occurs in

• liquids

• solids

• gases

Fill in the Blank

A ball with a mass of 15 kg sits at the top of a hill. The hill is 8.5 meters high. How much Gravitational Potential energy does the ball have?

Multiple Choice

Which type of energy is transferred between two objects touching each other due to the temperature difference between them?

• nuclear energy

• kinetic energy

• thermal energy

• potential energy

Multiple Choice

An __________________ is a flat surface that is raised higher at one end in order to move objects up or down.

• Lever

• Pulley

• Inclined Plane

• Wedge

Multiple Choice

What type of lever is this?

• First Class

• Second Class

• Third Class

​Lesson Objectives

• Describe and differentiate between types of radioactive decay

• Describe how radiation affects living and non-living things

• Understand how People use radioactive materials

• Differentiate between nuclear fission and fusion

  • Explain the advantages and disadvantages of nuclear energy

How was Radiation Discovered?

• 1896-Henri Becquerel tests the development of X-rays by placing paper under a plate and exposing it to the glowing mineral Uranium

  • Found that images were left on the paper with and without sunlight

  • Becquerel concluded that Uranium releases some sort of energy he called nuclear radiation

• Marie Curie, an associate of Becquerel, named the release of the energy nuclear radiation radioactivity

• Radioactivity: The process by which an unstable nucleus gives off nuclear radiation

  • also called radioactive decay

Different types of Radioactivity

• The nuclei of some atoms are not stable

  • During radioactive decay, the nucleus of these atoms release particles and energy

• Three different types of Radioactivity exist

Alpha Decay

• Alpha Particle: Made up of two protons and two neutrons

  • Recall: the mass of the nucleus is equal to the sum of the protons and the neutrons in an atom, so an alpha particle has a mass of 4

• Alpha Decay: The release of an alpha particle from the nucleus

• Many large radioactive atoms break apart by releasing an alpha particle

  • When an alpha particle is released, it changes into the nucleus of another element

    • The mass of the two elements is equal to the mass of the original element

Beta Decay

• Beta Particle: an electron or positron that is released by an atom

  • A positron is a particle the same size as an electron with a charge of +1

• Beta particles are so small that they do not affect the mass of an atom, so their loss does not change the mass of the atom

• During Beta Decay, a neutron becomes a proton, and an electron leaves the atom

  • Mass and charge are conserved

  • Because there is a new number of protons in the nucleus, the atom changes to a new element

Gamma Decay

• Gamma Decay: Particles in the nucleus move and change position, but the mass and charge of an atom do not change

  • Releases waves of energy that are emitted, called Gamma Rays

• Gamma Decay often occurs at the same time as alpha and beta decay

How does Radiation affect Matter?

• Particles and rays of nuclear radiation have large amounts of energy and move through matter.

• Each type of radiation has different strengths/abilities to penetrate matter

  • Alpha Particles have the most mass, so they tend to be stopped the easiest

  • Beta Particles are much smaller and go through cloth/paper, but can be stopped by a thin layer of metal

  • Gamma Rays have no charge or mass and can only be stopped by very dense materials

• As radiation hits atoms, the atoms lose electrons and change

Amounts of Damage caused by Radiation

• Gamma radiation can cause changes deep inside matter because of how easily it penetrates materials.

• Beta Radiation causes damage closer to the surface of matter because it does not penetrate as deeply.

• Alpha Particles have a hard time penetrating matter, but if something happens to allow it to do so, it can cause the most damage out of all the types of radiation

Radioactive Decay

• All radioactive isotopes decay at a particular rate

• Half-Life: The amount of time that it takes for one-half of the nuclei of an isotope to decay

  • The half-life is the same for all samples of a specific isotope, and never changes

• The half-life of different isotopes can be used to calculate how old an object is

Multiple Choice

Radioactive materials have unstable...

• electrons
• protons
• nuclei
• neutrons

Multiple Choice

The type of radioactive particle that can be stopped by a sheet of paper are.....

• alpha particles

• beta particles

• gamma rays

• positrons

Multiple Choice

Positively charged particles that consist of two protons and two neutrons are called

• alpha particles
• beta particles
• gamma rays
• neutron emissions

Reorder

In order of most to least penetrating radiation we have

• Gamma

• Beta

• Alpha

1

2

3

• 1
• 2
• 3

How are Atoms Broken Apart?

• Nuclear Fission: The process by which the nucleus of a heavy atom splits into two or more fragments

  • Releases neutrons and energy

• Some atoms undergo fission naturally

  • Example: Isotopes of Uranium

• Large atoms can be forced to undergo fission by hitting the nucleus of an atom with a neutron

  • The collision causes some of the mass of the products to be converted into energy

Energy from Matter

• The amount of energy given off by one uranium nucleus is very small

• Multiple Uranium atoms can be held in a sample

  • When one Atom splits, it releases neutrons that collide with another atom, starting a chain reaction that releases large amounts of energy.

• Nuclear Chain Reaction: A continuous series of nuclear fission reactions

Nuclear Chain Reactions

• Uncontrolled nuclear chain reactions release large amounts of energy quickly

• A nuclear chain reaction can be controlled by limiting the ability of neutrons to collide with uranium atoms

• Nuclear power plants use controlled chain reactions

  • Control rods absorb neutrons and slow down the chain reaction

  • The heat from the reaction is absorbed by a coolant, usually water, which is turned to steam that is used to turn a turbine and generate electrical energy

Pros of using Nuclear Power

• Nuclear power plants require less fuel to operate

  • Generate less pollution

  • Are less expensive

• Nuclear Power decreases the amount of Fossil fuels used

  • Fewer gases are released in the atmosphere

Cons of Using Nuclear Power

• Accidents that occur at a nuclear power plant can have a devastating effect on the surrounding environment.

  • The Chernobyl meltdown spread radioactive material that reached all the way to North America.

• The fuel rods used to absorb neutrons become radioactive waste that will take thousands of years to break down to a safe level

Nucelar Fusion

• Nuclear Fusion: The process by which nuclei of small atoms are combined to form a new, larger nucleus

  • The process of combination releases energy

• Fusion is hard to accomplish because the two positively charged nuclei normally repel each other

  • Requires temperatures high enough to force atoms into the plasma state of matter

    • Over 40,000,000 °C

    • Happens naturally in stars

Pros and Cons of Nuclear Fusion

• We currently do not use Fusion to generate energy, but research is being done to solve the two main problems.

  • Too hard to control the temperatures needed

  • The amount of energy needed to cause fusion is less than what would be generated.

• If Fusion power plants were to be developed, they would be the cleanest source of energy because they do not generate radioactive material or pollutants

Multiple Choice

_______________ is the process by which unstable atoms emit radiation until they become stable.

• Radiation
• Chemical Reaction
• Radioactive Decay
• Isotopes

Multiple Choice

What is the main difference between nuclear fission and nuclear fusion?

• Fission splits atoms, fusion combines them

• Fusion splits atoms, fission combines them

• Fission uses uranium, fusion uses carbon

• There is no difference

Multiple Choice

Advantage or Disadvantage: Nuclear waste is quite toxic and difficult to dispose of safely.

• Advantage

• Disadvantage

Multiple Choice

Requires temperatures in excess of 40,000,000 degrees celsius.

• Fission
• Fusion

Multiple Choice

Advantage or Disadvantage: Nuclear power is cheap to generate and is energy efficient.

• Advantage

• Disadvantage

Multiple Choice

When small nuclei combine to produce a nucleus of greater mass

• Fusion
• Fission
• Chain Reaction

Multiple Choice

What is the primary process used in nuclear reactors to produce energy?

• Nuclear fusion

• Nuclear fission

• Chemical reaction

• Solar power