Every fact in the three heat and temperature lessons is listed here with where it comes from. The numbers in [brackets] on the lesson pages link to this list.
How we rate sources
High: space agencies (NASA), peer-reviewed open textbooks (OpenStax, Rice University) and professional scientific societies (American Physical Society).
Medium-high: reputable science news reporting directly on a primary document.
Medium: single-author essays and popular history sites. We only use these for history details, and never on their own: each one is paired with a second source.
Wikipedia was not used as a source. Numbers are rounded (for example 9.8 m/s² for Earth's gravity). The text was drafted with help from AI (Claude) and then checked against these sources. Corrections: hello@echoesof.science.
Where the lessons simplify: the specific heat values (OpenStax) are rounded table values; real materials vary a little with temperature and composition. In everyday language 'heat' and 'temperature' are mixed up; the lessons for 10–11 and 15–16 keep them apart (heat is energy that moves because of a temperature difference). The insulation experiments use warm tap water rather than hot water for safety, so the temperature differences are small and results may be close; repeat readings help. The youngest lesson says that trapped air keeps things warm; air is a poor conductor of heat, but in a real coat other effects also play a part.
All sources
[1] Physics, 11.1 Temperature and Thermal Energy
OpenStax, Rice University · Reliability: High
Type: Peer-reviewed open textbook
Temperature is defined as what we measure on a thermometer; faster-moving molecules have greater kinetic energy; thermal energy is linked to the kinetic energy of the particles (molecules or atoms) of a substance; water boils at 100 °C (212 °F, 373.15 K) and freezes at 32 °F (273.15 K); zero on the Kelvin scale is absolute zero; T(K) = T(°C) + 273.15; in an alcohol thermometer the liquid expands as it warms.
[2] Physics, 11.2 Heat, Specific Heat, and Heat Transfer
OpenStax, Rice University · Reliability: High
Type: Peer-reviewed open textbook
Energy is transferred from the hotter object to the colder one until they are in thermal equilibrium (same temperature); Q = m·c·ΔT, where c is the specific heat, the heat needed to raise 1.00 kg by 1.00 °C, in J/(kg·°C); a change of 1 °C equals a change of 1 K. Values (J/(kg·°C)): water 4186, human body 3500, ice 2090, wood 1700, air 1015, aluminium 900, glass and concrete 840, iron/steel 452, copper 387, gold 129, lead 128. Example: heating a 0.500 kg aluminium pan with 0.250 kg of water from 20.0 °C to 80.0 °C takes 89.8 kJ (water 62.8 kJ, pan 27.0 kJ). Conduction is heat transfer through direct physical contact (a burner heating a pan); convection is heat transfer by the movement of a fluid (boiling water, hot air rising in thunderstorms); radiation is heat transfer by emitted or absorbed electromagnetic radiation (a fire, sunlight warming Earth) and needs no medium.
NOAA National Weather Service, JetStream · Reliability: High
Type: Government weather service education page
Radiation is the transfer of heat energy through space by electromagnetic radiation, felt when standing near a fireplace or campfire; the Sun's radiation strikes the Earth's surface and warms it; conduction is the transfer of heat energy from one substance to another or within a substance: the handle of a metal spoon in hot soup soon becomes hot; conduction is very effective in metals, but air conducts heat poorly; convection is the transfer of heat in a fluid, seen in boiling liquid; rising warm air is replaced by cooler, denser air, which we feel as wind.
Thermal conduction is the transfer of energy (heat) arising from temperature differences between adjacent parts of a body; heat always flows from higher to lower temperature; the rate of flow is proportional to the cross-sectional area and the temperature difference and inversely proportional to the length (thickness): H = −k·A·(T₂ − T₁)/l; copper is a good thermal conductor and wood a poor one (its conductivity is about 3,000 times smaller); a material with a small thermal conductivity is a good thermal insulator.
Science Learning Hub – Pokapū Akoranga Pūtaiao, University of Waikato (New Zealand) · Reliability: High
Type: University science education site (government funded)
Heat always moves from a hotter object to a colder one; keeping warm means slowing this transfer by insulating; trapping air in layers is a very effective way to insulate; penguins trap air in their feathers and cats fluff up their fur; more or thicker layers of clothing insulate better; polystyrene and plastic foam insulate because they contain small trapped air bubbles; double glazing traps air between two sheets of glass; metals are good conductors.