PhySci 3

• Protostar:

  • A very young star that is still gathering mass from its parent molecular cloud
  • Protostellar phase is the earliest one in the process of stellar evolution
• Stellar evolution:

  • Process by which a star changes over time
  • Lifetime of a star depends on its mass, ranging from a few million years for the most massive to trillions of years for the least massive
  • Lifetime of the least massive stars is considerably longer than the age of the universe
• Nebulae are made of gases and dusts.
• STELLAR NUCLEOSYNTHESIS process by which elements are formed within the stars as a result of nuclear fusion.
• NUCLEAR FUSION the process by which multiple nuclei joined together to form a heavier nucleus.
• Hydrogen nuclei fuse together at high temperatures (nuclear fusion) to form helium nuclei. This releases energy.
• When a star runs out of hydrogen in its core, it becomes a red giant, unable to generate heat, leading to its contraction and expansion
• The red giant star becomes exhausted of nuclear fuel, and the outer material is blown off into space, leaving the inert Carbon, known as a white dwarf
• A giant cloud of gas and dust is known as a nebula
• A protostar is formed from a nebula due to gravity pulling Hydrogen gas together until it spins faster and faster and becomes ignited
• A main sequence star forms when nuclear fusion occurs at the core, converting Hydrogen into Helium, making the star stable and glow
• A black dwarf is the remains of a white dwarf that cooled down and no longer emits light and heat
• A neutron star is believed to be formed from a supernova explosion and is the smallest star
• A supernova explosion releases a large amount of energy, dispersing elements into space
• A black hole is a region in space where gravity is so strong that no matter can escape from it
• A more massive main sequence star evolves into a red supergiant, the largest known star, where Carbon fusion still occurs and Oxygen is formed
• Plural of nebula is nebulae
• Faster rate of capturing neutron before radioactive decay occurs is known as the r-process
• Nuclear fusion in red supergiant stars that creates heavy elements up to Iron is called the alpha ladder process
• Slow rate of capturing neutrons with a faster rate of radioactive decay is referred to as the s-process
• Formation of light elements like Helium and Hydrogen is part of the big bang nucleosynthesis process
• Conversion of three Helium-4 nuclei into Carbon in a red giant star is known as the tri alpha process
• Formation of elements heavier than Iron occurs in the supernova process
• Nuclear fusion reaction converting Hydrogen into Helium is called the proton-proton chain
• Addition of neutrons to form heavier nuclei is known as neutron capture
• Stellar nucleosynthesis is the process by which elements are created within a star
• Conversion of Hydrogen into Helium in massive stars is part of the CNO cycle
• Formation of stars:

  • Nebula space collapses due to gravity, forming a protostar
  • Nebular fusion occurs at the center, converting hydrogen into helium and forming a main sequence star
  • Main sequence stars can be average or massive
• Life cycle of a massive main sequence star:

  • Runs out of hydrogen fuel, expands, and cools down, becoming a red supergiant
  • Continues to fuse with heavy elements until iron is formed in the core
  • Iron formation leads to the star becoming a supernova after hundreds of years
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• Secretary: 'Leonor Magtolis Briones'
• Undersecretary: 'Diosdado M. San Antonio'
• This Self-Learning Module (SLM) is prepared so that learners can continue their studies and learn while at home. Activities, questions, directions, exercises, and discussions are carefully stated for understanding each lesson.
• Pre-tests are provided to measure prior knowledge on lessons in each SLM. This will indicate if learners need to proceed on completing the module or if they need to ask for assistance for better understanding of the lesson. At the end of each module, learners need to answer the post-test to self-check their learning. Answer keys are provided for each activity and test.
• Notes to the Teacher are provided for strategies and reminders on how they can best help learners on their home-based learning.
• Learners are expected to define collision theory, describe how it affects the chemical reaction, explain the different factors affecting the rate of reaction, and create an experiment video showing the effects of concentration, temperature, and particle size on the rate of reaction.
• Module parts


  • Lesson 1 – Collision Theory
  • Lesson 2 – Factors Affecting the Rate of Chemical Reactions
• The module is divided into two lessons: Lesson 1 – Collision Theory and Lesson 2 – Factors Affecting the Rate of Chemical Reactions
• Chemical reactions have been a part of this world ever since everything began