Why can a pressurised hot-water system become so dangerous when pressure is suddenly released? In this episode of The Copper Connection Podcast, Chris Bailey explains the scientific principles behind temperature, heat and change of state for plumbing and heating apprentices.

Covering Unit 303, Phase 2, Session 2, this episode supports the 9289 Plumbing and Domestic Heating Technician apprenticeship and helps learners prepare for the Scientific Principles assessment criteria:

• AC 3.1: The relationship between Celsius and Kelvin temperature scales

• AC 3.2: The principles associated with changes of state

• AC 3.3: Sensible heat and latent heat in liquids and gases

You will learn:

• How to convert between Celsius and Kelvin

• What ΔT means in heating and heat-loss calculations

• How solids, liquids and gases change state through melting, evaporation, condensation and freezing

• Why water expands when heated, freezes, and turns to steam

• Why frozen water can split pipework

• How pressure changes the boiling point of water

• Why unvented cylinders, sealed systems, pressure-relief valves and safety cut-outs must be treated with respect

• The crucial difference between sensible heat and latent heat

• Why superheated water can flash rapidly into steam when pressure is released

This is not abstract science for the sake of an exam. It is the knowledge behind the safety procedures, system design and commissioning decisions you will encounter throughout your plumbing and heating career.

Follow The Copper Connection Podcast for practical, exam-focused support for plumbing, heating and building-services learners.

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EPA reforms are generating plenty of confusion across plumbing and building services education, but what has actually changed for current learners?

In this episode, Chris Bailey breaks down the move from End-Point Assessment (EPA) to Apprenticeship Assessment and explains what it means in practice for:

• City & Guilds 9289 Level 3 Plumbing and Domestic Heating Technician apprentices
• City & Guilds Level 2 Plumbing learners
• T-Level Building Services Engineering students
• Tutors, assessors and employers supporting apprentices

You will learn why the current ST0303 assessment model remains unchanged for existing plumbing apprentices, what the January 2026 9289 v1.2 update really means, and why T-Level BSE assessments are not affected by apprenticeship EPA reforms.

Chris also tackles five common misconceptions, including whether assessments are moving earlier, whether colleges will now mark EPA work, and whether learners need to revise different content.

For the free tutor resource pack and the EPA Change Navigator chatbot, visit:

https://thecopperconnectionpodcast.co.uk/epa-changes

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Struggling to connect Unit 303 "Electrical and Scientific Principles – Units of Measurement" with what you actually do on site? In this Phase 1 Unit 303 episode of The Copper Connection Podcast, Chris Bailey turns SI units and derived units into practical tools for UK plumbing and building services students.

You'll start with the seven base SI units – metre, kilogram, second, ampere, kelvin, candela and mole – and see which ones matter most in everyday plumbing tasks. Then we dive into temperature (Celsius vs Kelvin), pressure and head (pascal, kilopascals, bar and static head), and capacity in litres and cubic metres. From there, we break down key derived units: area in m², volume in m³, velocity in m/s, and density in kg/m³, including water's expansion and why pipes can burst when it freezes.

We'll also tackle the non-SI units you still meet on UK sites: imperial length and weight, old gas meters in cubic feet per hour, and BSP pipe thread sizes that mix inches with metric diameters.

Ideal for T-Level BSE, Level 2 and Level 3 plumbing learners and apprentices revising Unit 303, this episode helps you use units confidently in drawings, calculations and commissioning – and turns "science" into something that feels site-ready.

🔗 Handouts, worksheets and revision resources at thecopperconnectionpodcast.co.uk

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electrical and scientific principles, unit 303 9289, 9289 phase 1 science, SI units plumbing, plumbing apprentice science revision, t level bse revision, city and guilds level 3 plumbing, ST0303 apprenticeship, T-Level building services engineering, copper connection podcast, Chris Bailey plumbing podcast

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