German researchers conducted clinical interviews designed to confirm students’ difficulties with energy. It determined that a new teaching approach to heat, temperature, and energy is necessary based on the second law of thermodynamics.

Evidence-based suggestions

• Differentiating between heat and temperature needs addressing in the curriculum.
• A conceptual framework to support thermal interaction as an exchange of extensive quantity heat (energy) that runs spontaneously as long as there is a temperature difference needs to be developed.
• Students have a vague concept of energy. Ideas of energy transformation, conservation and degradation need emphasis, not learning a list of energy forms.
• Degradation is an important concept to develop because everyday experiences do not support the idea of energy conservation.

Learners’ ideas

• A small majority of students believed that temperature is a direct measurement of heat.
• Students believe that temperature is a variable that can be measured/quantified while heat was not.
• Students viewed heat as an extensive property and temperature as the amount of heat contained in a body.
• Some viewed temperature as something that passes from one body to another, the degrees indicating the amount of temperature transported.
• Some students argued that the sum of temperatures of two interacting bodies had to be the same before and after the interaction.
• When discussing particle behaviour, students could state that in solid bodies particles move at low speed, or do not move, that particles in gases and liquids are easier to set into motion and that the particles will eventually slow down and stop on their own.
• Students describe the heating of a body as being explained by particles rubbing against each other.
• Some students thought of energy as being like a force which comes in various forms. They thought it is contained within bodies and does not get lost.
• Energy is not lost but exhausted by bringing about an effect or action or energy is used up in processes.
• Students may describe temperature differences in materials as being due to different qualities of the materials or the ease with which heat enters or leaves. For example, they may think different materials attract or retain heat to differing extents or that particles that are not equally close to each other will retain different heat.
• Students are unaware that every cooling process requires an interaction partner.
• Half of the students asked believed that when at the same temperature a cup of coffee and the room it is in have the same heat.
• The idea of a reduction in kinetic energy by heating was not well developed by many students.

Study Structure

Aims

To investigate students' conceptions of the second law, focussing on irreversibility. It examined energy degradation and the tendency towards disorder.

Evidence collection

Evidence was collected via a set of clinical interviews based on a set of thermodynamics problems for students to solve during the interview. The authors conducted the interviews which were recorded and transcribed.

Pilot data and the data discussed in the article were used to create a coding scheme to classify pupil responses. The authors then tried to describe the conceptions pupils used in their explanations.

Details of the sample

The sample consists of 34 students from 9 classes in 7 top-level grammar schools with students aged 16-18.