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Children's Chemistry Reasoning

What is the project?

This inter-disciplinary project, combining cognitive psychology paradigms with education and chemistry approaches, aims to explore children's knowledge of how substances mix prior to systematic chemistry instruction. More specifically, the project aims to study children’s earliest understandings of chemistry, with experiments on how 4- to 11-year-olds understand what happens when substances / materials mix. When a solid is mixed with a liquid, it might dissolve forming a solution, with the solid disappearing in the liquid, or it might suspend in the liquid, with particles diffused throughout, or it may do nothing, just floating/sinking, or the two might be involved in a chemical reaction, forming new substance(s). The outcome depends on various chemical properties of the different substances, including substance-kind (roughly, different molecular structure and bonding within molecules) and form (roughly, depending on bonding between molecules.

We focus on mixing, because it is one of the earliest chemistry concept children are deemed capable of grasping. Very little work – either in cognition or education – concerns such young children. Most existing studies of chemical understanding used interviews, suggesting little or no conception of the particulate nature of matter, with primary school students attending to macroscopic properties of substances instead (i.e., what they can see). Briefly, by particulate nature of matter we mean the idea that substances are made up of invisible, sub-microscopic particles, with molecules being the smallest particles of most substances. Some knowledge of the particulate nature of matter is necessary to understand substances and how they interact with each other. Therefore, investigating the emergence of this level of understanding is important for effective science teaching.

Children’s chemistry understanding is usually studied in a qualitative manner, leading to an impression of fairly late emerging knowledge. Instead, this project will use quantitative and largely non-verbal cognitive psychology methods because of their effectiveness at uncovering early understanding in other areas.  For example, research from intuitive biology, psychology and biology indicate that limits on children’s explanations reflect limitations of their vocabulary, not limits of their understanding. We know this because more sensitive, less verbal, experimental psychology paradigms unearthed substantially earlier understanding from pre-school age. We focus on everyday materials rather than strictly chemical substances (sand, stone, wood, plastic, metal, spices, flour, vitamins, sugars, salts, baking soda/powder, instant coffee, cocoa, soap, dye, etc.), because children may reason better about familiar content (and also for safety).

The aim is to learn about children’s natural approach to chemical phenomena before instruction. The value of our approach is three-fold. First, we focus on children younger than typically studied. Second, this is possible because of sensitive experimental paradigms. Third, our interdisciplinary approach involving researchers in cognitive psychology, education and chemistry will allow us to apply insights from the behavioural sciences to a technically distant topic. Hopefully, the results of this project will shed light on how very early chemical understanding relates to understanding in other domains, with implications for science and chemistry education.

Why this research?

Young children show sophisticated reasoning about the physical world. This reasoning ability is used to support later learning of more complex scientific concepts. However, the abilities of young children to reason about the chemical world have not been well explored. Teaching methods are influenced by the knowledge children bring to the classroom before instruction begins. In learning to read, for example, kids make use of their existing language knowledge. By investigating what young children know about the chemical processes in their everyday lives this project hopes to inform science education. These chemical events may be sugar dissolving in water, soap making bubbles, oil floating in water or even food changing by the process of cooking. By allowing teachers to make use of children’s existing knowledge about the physical world more appropriate age-specific lesson content can be devised. The research also has potential to inform psychology by shedding light on how young children learn about the physical world around them.

What does it involve?

All of our tasks are designed to be engaging and fun for all ages in the study. In this enjoyable study children get to observe and comment on how every day substances react with each other when mixed. They will have a chance to discuss what happens during mixing processes and why these processes happen. All sessions are short, generally lasting about 20 minutes. Of course, participation will depend on both the parents and the child's willingness to take part. All personal information will remain confidential and will be used for research purposes only. 

Get Involved

If you or your children would like to get involved in this research please contact Michelle Ellefson ( to find out more and to arrange a session. The project involves children from reception class up to year 6 (ages 4 – 11) as well as adults. If you are a teacher, a science coordinator or head teacher and would like to get involved as part of a school science programme then please contact Connor Quinn. We have worked with several schools to great success. The individual sessions are designed in such a way so that we might conduct the research with a minimum of disruption to students and classes. Our study requires only quiet space to work and can provide an enjoyable complement to the science learned in the classroom. We appreciate the various constraints on classes across the school year and are happy to discuss individual arrangements with schools.


Want to know more?

You can download results and grant reports from: More Chemistry!


This research is funded by the Leverhulme Trust (Grant no. RPB-115). They featured our project in the Leverhulme Trust April 2011 newsletter ( The project involves a collaboration between the University of Cambridge (Dr Michelle EllefsonDr Keith Taber, Connor Quinn, and Fran Riga) and UCL (Dr Anne Schlottmann,  Julia Hill, and Fahreen Walji ).  The team at UCL have also created an excellent website describing the study ( The research has received ethical approval from the Psychology Ethics Committee (No. 2011.48).