Power: watts and energy per second
CONCEPTUALDefine power as the rate of energy transfer (power = energy ÷ time, measured in watts), and compare energy transfer rates in different everyday contexts
Mastery Evidence
- States the definition of power and gives its unit (watt)
- Uses P = E/t to calculate power, energy, or time given the other two quantities
- Compares the power ratings of common appliances and explains what the rating means
- Explains why a higher-powered device does the same job faster but uses more energy
Assessment Prompt
“If [child] was comparing a 100 W light bulb with a 10 W LED, could they explain what those numbers mean and calculate how much energy each uses in an hour?”
Curriculum Standards1 alignment
KS3.Sci.Phys.Energy.4The national curriculum in Englandpower as the rate of transfer of energy; comparing energy transfers in different contexts
Prerequisites1
- Energy can't be created or destroyedhardAges 11—12
Show full prerequisite tree
- Energy can't be created or destroyed hard
Power is the rate of energy transfer — the concept of energy stores and conservation must be understood before rates can be discussed
- Naming types of energy hard
Explaining conservation of energy and dissipation requires energy store and transfer vocabulary
- Energy stores and transfers hard
Conservation of energy is a property of energy stores and transfers — the stores and pathways model must be established first
- Speed and energy hard
KS3 kinetic energy store extends KS2 US understanding that faster-moving objects have more energy
- Naming types of energy hard
Relating an object's speed to its energy requires 'kinetic energy' vocabulary
- Drawing Force Diagrams soft
Understanding pushes and pulls as forces is supported by the arrow representation of magnitude and direction
- Naming types of energy hard
Identifying energy stores and transfer pathways is a formalisation of the energy type vocabulary introduced earlier
- Greenhouse Gas Science soft
KS3 energy stores and radiation transfer provides the physics vocabulary for explaining how greenhouse gases re-emit infrared
- Global Wind Patterns hard
Greenhouse radiation physics provides the energy imbalance context that drives differential heating and global circulation
- Seasons & Weather Patterns soft
Climate as long-term patterns benefits from knowing seasonal patterns
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Geography & Local Weather hard
Climate concept requires knowing that different places have different typical weather
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Geography & Local Weather hard
Climate zones formalize the concept of different weather around the world
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Seasons & Weather Patterns soft
Climate as long-term patterns benefits from knowing seasonal patterns
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Geography & Local Weather hard
Climate concept requires knowing that different places have different typical weather
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Shapes of land and water hard
Must know land and water features before learning where water is found on Earth
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Heating & Cooling Changes soft
Understanding state changes supports knowing water as solid (ice) and liquid
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Heating & Cooling Changes soft
Water cycle benefits from curriculum states of matter (heating/cooling changes state)
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Temperature & Thermometers soft
Water cycle evaporation relates to temperature (heat drives evaporation)
- Sunlight warms things up soft
Sun drives weather builds on curriculum sunlight warms Earth's surface
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- What Causes Wind hard
Sun-driven weather systems extend the basic wind-cause concept to global scale
- Seasons & Weather Patterns soft
Climate as long-term patterns benefits from knowing seasonal patterns
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Geography & Local Weather hard
Climate concept requires knowing that different places have different typical weather
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Shapes of land and water hard
Must know land and water features before learning where water is found on Earth
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- Heating & Cooling Changes soft
Understanding state changes supports knowing water as solid (ice) and liquid
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Heating & Cooling Changes soft
Water cycle benefits from curriculum states of matter (heating/cooling changes state)
- States of Matter Vocabulary hard
Describing and measuring changes of state requires solid/liquid/gas vocabulary and the term 'change of state'
- Drawing Particle Diagrams hard
Observing and describing change of state requires reading particle diagrams showing how arrangement changes on heating or cooling
- Temperature & Thermometers soft
Water cycle evaporation relates to temperature (heat drives evaporation)
- Sunlight warms things up soft
Sun drives weather builds on curriculum sunlight warms Earth's surface
- Days, Weeks, Months & Years soft
Observing and describing seasonal changes requires basic date and time vocabulary (months, seasons, year)
- Ordering Events in Time hard
Understanding days/months/years builds on sequencing events chronologically
- What Causes Wind hard
Sun-driven weather systems extend the basic wind-cause concept to global scale
- How energy travels around hard
KS3 energy stores model extends KS2 US observation that energy is transferred by sound, light, heat and electric currents
- Light & Sound Vocabulary hard
Observing that objects need illumination to be seen requires the 'light source' vocabulary
- Naming types of energy hard
Describing energy transfer by sound, light, heat, and electric current requires energy type vocabulary
- Building a simple circuit hard
Must know circuits before understanding energy transfer by electric current
- Light & Sound Vocabulary hard
Understanding vibrating materials and sound requires 'vibration' vocabulary
- Communication with Light & Sound hard
Must understand how sound works before designing a communication device using it
- Light & Seeing in the Dark hard
Must understand how light works before designing a communication device using it
- Light & Sound Vocabulary hard
Observing that objects need illumination to be seen requires the 'light source' vocabulary
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