Lesson Plan: P2.5.06


LESSON PLAN
Teacher Subject Period Date Year Ability LSA/Other Support
Science

Context and
Landmark
Assessment		 P2.5.06
Landmark Assessment: Progress Observation Opportunity
Remember to have high expectations
Lesson Title: Today we are learning about
How do step-up and step-down transformers work?
Remember to check for PROGRESS
Focus on Knowledge, Skills and Understanding
Success Criteria: You will show your learning by...
  1. (Physics only) Students should be able to apply the equation linking the pds and number of turns in the two coils of a transformer to the currents and the power transfer involved, and relate these to the advantages of power transmission at high potential differences.
  2. (Physics only) A basic transformer consists of a primary coil and a secondary coil wound on an iron core.
  3. (Physics only) Iron is used [for a core] as it is easily magnetised. Knowledge of laminations and eddy currents in the core is not required.
  4. (Physics only) The ratio of the potential differences across the primary and secondary coils of a transformer Vp and Vs depends on the ratio of the number of turns on each coil, np and ns . EQUATION
  5. (Physics only) In a step-up transformer Vs > Vp
  6. (Physics only) In a step-down transformer Vs < Vp
  7. (Physics only) If transformers were 100 % efficient, the electrical power output would equal the electrical power input.
  8. (Physics only) Vs ? Is = Vp ? Ip Where Vs ? Is is the power output (secondary coil) and Vp ? Ip is the power input (primary coil). power input and output, in watts, W
  9. (Physics only) Students should be able to explain how the effect of an alternating current in one coil in inducing a current in another is used in transformers
  10. (Physics only) Students should be able to explain how the ratio of the potential differences across the two coils depends on the ratio of the number of turns on each
Think about how you can match the needs of ALL students
Keywords:
  • Transformer: A transformer is an electrical device that changes the voltage of an AC supply. (2)
  • primary coil (1)
  • Step down transformers: Step down current, step down voltage. (1)
  • Current: An electric current is a flow of electric charge. (1)
  • Power: Power is a measure of how quickly energy is transferred. The unit of power is the watt (W). (1)
  • Step Up transformers: Step up voltage, step down current. (1)
Links: Literacy, Numeracy, SMSC, British values
Memory Anchor:

AFL/Key Questions:
  1. (Physics only) How does the equation linking the pds and number of turns in the two coils of a transformer link to the to the currents and the power transfer involved. Relate these to the advantages of power transmission at high potential difference.
    At the end of the power station there is a step up transformer which increases the voltage but decreases the current therefore less energy is lost by heat. Before the current reaches homes and industry a step down transformer steps up the current and steps down the voltage.
  2. (Physics only) What is the basic structure of a transformer?
    (Physics only) A basic transformer consists of a primary coil and a secondary coil wound on an iron core.
  3. (Physics only) Which metal is used for the core in transformers?
    (Physics only) Iron is used [for a core] as it is easily magnetised.
  4. (Physics only) The ratio of the potential differences across the primary and secondary coils of a transformer (Vp and Vs) depends upon the ratio of what?
    The potential differences across primary and secondary coils of a transformer depend upon the ratio of number of turns on each primary and secondary coil (np and ns)
  5. (Physics only) In a step-up transformer which has the greatest potential difference, primary (Vp) or secondary (Vs) coils?
    In a step-up transformer Vs > Vp (Primary potential difference = Vp; Secondary potential difference = Vs)
  6. (Physics only) In a step-down transformer which has the greatest potential difference, primary (Vp) or secondary (Vs) coils?
    In a step-down transformer Vp > Vs (Primary potential difference = Vp; Secondary potential difference = Vs)
  7. (Physics only) What would the relationship be between total power input and output in a transformer if it were 100% efficient?
    If transformers were 100 % efficient, the electrical power output would BE EQUAL to the electrical power input.
  8. (Physics only) Vp x Ip = the ______ _______ (primary coil). power input Vs x Is = the _______ ______ (secondary coil)power output
    Vp x Ip = the POWER INPUT(primary coil). Vs x Is = the POWER OUTPUT (secondary coil) (Ip = Current through primary coils Is = Current through secondary coils)
  9. (Physics only)Explain how the effect of an alternating current induces a current in another transformer.
    An alternating current in a transformer creates a changing magnetic field. A changing magnetic field also induces a changing voltage in a coil. This is the basis of how a transformer works: The primary coil is connected to an AC supply An alternating current passes through a primary coil wrapped around a soft iron core The changing current produces a changing magnetic field This induces an alternating voltage in the secondary coil This induces an alternating current (AC) in the circuit connected to the secondary coil
  10. (Physics only) How does the ratio of the potential differences across the two coils depends on the ratio of the number of turns on each?
    The ratio of the potential differences across the two coils depends on the ratio of the number of turns on each
Identify questions for high, middle, low and identify questioning techniques- Challenge questions

Learning Phases/Episodes
Think about how you can match the needs of ALL students
Differentiation: AGT, SEND, LLL, Disadvantaged
Remember to check for PROGRESS
Starter Activity Differentiation and Challenge question/task
  • Students to copy and complete the keywords.
  • Teacher reveals missing letters; Students correct mistakes;
  • Discuss the scientific meanings of the words.
  • Students to write down the definitions of the most important / new keywords.
  • Discuss the 'Memory Anchor'.
    • What does it show?
    • How does it relate to the what we are learning about today (title)?
Think about PACE – Develop, consolidate and deepen knowledge, skills and understanding
Teacher or Student lead? Differentiation and Challenge question/task
Progress Check Extension
Remember to give time to apply knowledge, skills and understanding
Teacher or Student lead? Differentiation and Challenge question/task
Progress Check Extension

Teacher or Student lead? Differentiation and Challenge question/task
Progress Check Extension

Teacher or Student lead? Differentiation and Challenge question/task
Progress Check Extension


Plenary Differentiation and Challenge question/task
  • Students to answer the 'Key Questions' with learning partners.
Progress Check
  • Teacher to reveal and discuss the answers to the questions.
 Extension
  • What have learnt about the 'Big Ideas' today?

Homework Differentiation and Challenge question/task