Physical Science Review

Big Bang theory

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Open Ended

What do you know about the Big Bang theory?

The origins of the universe 

• This theory suggests that the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today

• Scientists believe that the solar system formed about 4,500 million years ago in a huge cloud of gas and dust called a nebula.

Evidence 

- Mathematical formulas and models has formed much of our understanding of the Big Bang Theory so far. However evidence exists to support this theory. 

- One form of evidence is that Scientists believe we can see the "echo" of the expansion through a phenomenon known as the cosmic microwave background.

Evidence 1 - COSMIC MICROWAVE BACKGROUND 

Poll

If you were to point a satellite dish at into any point in space, what would you expect to hear?

• Nothing

• Quiet noises like the wind blowing

• indistinguishable noise

• Static

If you were to point a satellite dish into empty space you would get static  

The universe has an underlying static - Cosmic microwave background  

Before the Bang

• Scientists believe that before the Big Bang space and time didn't exist and all that existed was energy

• The Big Bang occurred when all of this energy was concentrated into a single point called 'singlularity'

• Space began to expand quickly and the temperature was hot (an estimated 100 million trillion trillion degrees!)

Cosmic Microwave Background 

• Big Bang Theory suggests that the universe was a very hot place and that as it expands, the gas within it cools 

• As the universe began to cool, radiation began to fill the universe as a remnant of the heat left over - this is called 'Cosmic Microwave Background'

• The cosmic microwave radiation is like an 'afterglow' of radiation

Nucleosynthesis

Formation of elements in stars

Multiple Choice

Which subatomic particle identifies the type of atom (element)?

• proton

• neutron

• electron

Multiple Choice

Which subatomic particle has a positive charge?

• proton

• neutron

• electron

Multiple Choice

Which subatomic particle has no charge?

• proton

• neutron

• electron

Write down your answers and answer on the next slide.

Multiple Choice

What elements were pictured in the previous slide?

• H

  Li

  He

  H

  He

  H

• 1. H
  2. Be
  3. H
  4. He
  5. He
  6. H

• 1. He
  2. N
  3. Li
  4. Li
  5. Be
  6. H

Multiple Choice

Which element fuses in a main sequence star?

• Hydrogen

• Helium

• Carbon

• Oxygen

Multiple Choice

Why does helium sink to the middle of the core?

• Helium has more mass

• Helium has less mass

• It doesn't

Go here

https://public.nrao.edu/gallery/animation-of-stellar-nucleosynthesis-inside-a-red-giant/

Multiple Choice

The fusion of ____ in the core indicates the start of a red giant.

• hydrogen

• helium

Multiple Choice

What is the heaviest element a supergiant can produce?

• hydrogen

• carbon

• silicon

• iron

Multiple Choice

Gold is heavier than iron. How does gold exist?

• planetary nebula

• supernova

• main sequence fusion

• supergiant fusion

Go here

https://public.nrao.edu/explore/milky-way-explorer/?location=astrochemistry

Multiple Choice

What type of electromagnetic wave allows astronomers to see dark clouds?

• infrared

• ultraviolet

• radio

• gamma

Atom: Nuclear Reactions

How are these 3 types of decay similar different from one another?

alpha decay / beta-minus / beta-plus

Multiple Select

Which subatomic particle/s is/are directly involved in nuclear reactions?

• protons

• neutrons

• the electrons outside the nucleus

Nuclear reactions can be:

natural or artificial

The next question can somehow tell if you've worked on part 3 of the playlist, and how much you have understood the concept of nuclear reactions so far...

Open Ended

Why would an element spontaneously undergo decay?

Why would an element spontaneously undergo decay?

The goal is to have a more stable nucleus.

NUCLEAR EQUATIONS

For a better analysis of nuclear reactions, EQUATIONS are used. So let's study/review how to write them!

Get ready for the next review question...

Multiple Select

By how much does the atomic number and mass number of an element decrease after going through alpha decay? Choose the two correct answers.

• Atomic number decreases by 2.

• Atomic number decreases by 4.

• Mass number decreases by 2.

• Mass number decreases by 4.

Multiple Select

Which of the following is TRUE about beta-minus decay?

• A beta-minus is ejected by the reactant.

• A beta-minus is taken in by the reactant.

• The number of protons is increased.

• The number of protons is decreased.

Multiple Choice

How do you compare the original element and the new element formed through beta-minus decay?

• The new element has an atomic number that is one MORE than the original.

• The new element has an atomic number that is one LESS than the original.

• The new element has a mass number that is one MORE than the original.

• The new element has a mass number that is one LESS than the original.

Open Ended

Briefly describe what happens in a beta-plus decay.

Beta-plus Decay

A proton transforms into a neutron (by ejecting a positron) decreasing the atomic number of the original element by one.