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methods & strategies

Don’t Forget the Demo!

How to choose quality demonstrations and maximize their use

Science and Children—November/December 2022 (Volume 60, Issue 2)

By Christopher Roemmele, Steven Smith, Sarah Nern, Brett Criswell, and Missy Holzer

Learning occurs through the interactions of students and teachers. These interactions help students achieve learning targets, such as those designed to support attainment of the Next Generation Science Standards (NGSS). Appropriately constructed, NGSS-aligned learning targets emphasize three-dimensional thinking through applying crosscutting concepts (CCCs), science and engineering practices (SEPs), and disciplinary core ideas (DCIs) to explore relevant phenomena. The very word education means a drawing out and bringing forth of critical characteristics, and as such, learning science should involve teachers seeking to draw out and refine student understandings. This can be accomplished through a multimodal, active process that scaffolds knowledge and skills over time. Demonstrations (hereafter “demos”) can serve this purpose, particularly those that challenge and support students as they make sense of a core idea. This article identifies key principles of quality demos and illustrates how to maximize those principles in specific lessons and units.

Why Do Demos?

Performing demos, which we define as the manipulation of materials and equipment for learners to observe one or more aspects of scientific principles or phenomena, provides students with the opportunity for engagement with SEPs and CCCs. While we often hear the phrase “children are natural (or naturally) scientists,” they still need their teachers to provide structure and guide their natural curiosity into something more scientifically meaningful (Worth 2010). The infusion of demos harnesses the curiosity of students and provides opportunities for a range of scientific activities and thinking, including recognizing patterns, identifying cause-effect relationships, constructing explanations, arguing from evidence, and demonstrating positive skepticism (NGSS Lead States 2013). Because science demos are multimodal instructional routines and entail speaking, writing (such as students writing predictions), numerous actions and visual stimulation, they can enhance your delivery and promote deeper conceptual understanding.

Demos support the vision of the NGSS because they evoke excitement and relate scientific processes to real-world experiences, both of which help support students as they “transition from their naive conceptions of the world to more scientifically based conceptions” (NGSS Lead States 2013). Demos serve many roles in the science learning process, including fostering student engagement, modeling concepts that may be difficult or impossible to observe in the classroom, providing assessment opportunities, and supporting storylines.

Due to time restrictions or uncertainty, teachers often shy away from using demos in the elementary classroom. However, the use of demos can positively impact students’ attitudes toward science as well as their achievement (Gurel 2016). We encourage teachers to widen their repertoire of science demos, especially ones when it is just you, the teacher, the materials, and your audience. We also advocate for implementing demos in various stages of a lesson—from the initial engagement through exploration in the heart of the lesson to applying understandings, as part of closure, or in an assessment (both formative and summative). The balance of this article provides examples of using demos in various stages of a lesson to support student learning.


Demos as Engagement (Anticipatory Sets) and Discrepant Events

Performing a demo which is a “discrepant event” can captivate and baffle young learners and often touch upon their sense of wonder. A discrepant event is a surprising and paradoxical phenomenon that is not what an observer (of any age) would normally expect. Ask young learners to predict and discuss what will happen, even convince them they may be correct, such as with a melting ice demo. A melting ice demo can entail adding ice cubes to a glass of fresh and salt water to compare and contrast how rapidly ice melts in either. By adding food coloring to both glasses, students can observe how melting ice diffuses evenly through the freshwater but pools at the top of the salt water for a distinct temperature and salinity difference. Their responses will identify prior-conceptions or misconceptions to target during teaching and learning the associated science concepts. This type of demo can not only engage students but also activates, assesses, and emphasizes the practices that scientists use to ask questions and investigate the natural world, exactly what NGSS would like teachers to do.

Demos as Models and Analogies

Many scientific ideas or concepts cannot be observed in the classroom. For example, local examples of erosion may not be accessible near a school community. However, a classroom demo could provide an effective model of the phenomena. This could be done by setting up a simple stream table in the classroom to help students understand how running water causes erosion (see Figure 1). Here, demos are used as a model (a two- or three-dimensional representation of the feature or phenomenon that has explanatory and predictive power), but they could also be used as an analogy (comparison) for the actual phenomenon. Models, modeling, and the use of analogies are used extensively by scientists as they answer their research questions, and by using them in the science classroom we are developing an understanding of the nature of science along with enhancing thinking skills (Coll, France, and Taylor 2005). In addition, by incorporating models and analogies into lessons, students develop proficiency in key SEPs (Developing and using Models, Asking Questions and Defining Problems), and key CCCs (Patterns, Cause and Effect, Systems and System Models).

Figure 1
A stream table can be used as a model and a demonstration.

A stream table can be used as a model and a demonstration.

When using a demo as a model or an analogy, teachers should assist students with mapping the models and analogies to the real entity. To help students correlate with the real phenomenon, use guiding questions and have students use a table or labeled drawings. An example is seen with the classic “Delicious Differentiated Weathering” demo (Francek 2002). In the demo students are presented (actual or photo) with a candy bar with nuts, nougat, caramel enrobed in chocolate. Each of these food items represents a mineral found in the rock granite, each of which weathers at a different rate to ultimately create soil or sand. By listing the minerals and the candy bar contents on the board in front of the class, visual connections can be made as the demo unfolds, and in this case, between how fast each of the food items disintegrate and how fast each of the minerals weather. Students reflect on this model when presented with another rock that is partially weathered and accurately relate the results of the demo showing that some minerals weather faster than others. Depending on the grade-band in which this demo is used, the mechanisms for weathering could be included. To extend the effects of a demo as a model or analogy, (1) consider leaving it in student view for the duration of the lesson; and (2) ensure the deficiencies of the model or analogy are touched upon by contrasting it with the “real world.” 

Demos as Assessment 

There are several ways a classroom demo could be used as an assessment tool. However, for students to appropriately construct explanations of the demo taking place, the assessment must include a way to gather feedback on the students’ perceptions of the demo (NGSS Lead States 2013). During a teacher-led demo, you might choose to either repeat a previously taught concept or model a different way to understand a concept. In both cases, student assessment might take the form of observations and explanations, either written or oral, over what has occurred during the demo. Another method of using a demo for assessment would be to have the student perform a demo to illustrate their understanding of previously investigated topics. For example, students might physically show that the slope of a ramp can impact the speed and the momentum of a ball at the end of the ramp (see Figure 2). Teachers can take advantage of digital note booking to have students document and explain their understanding of the demos they perform. Digital note booking might involve instructing students (individually, small group, in-person, or remotely) to perform a demo and include photos or short videos documenting the important parts or moments of that demo. Students complete their digital notebook entries with written explanations of the “what” and “why” for the demo performed. Providing opportunities for students to reflect on what has happened during a demo is not only an effective method of assessment but has also been shown to improve student learning of the science content that is being demonstrated (Crouch et al. 2004).     

Figure 2
A student conducts a demonstration of how the slope of a ramp can influence the speed and momentum of a ball.

A student conducts a demonstration of how the slope of a ramp can influence the speed and momentum of a ball.

Demos as Supporting Storylines  

Demonstrations can be integral to building a coherent conceptual storyline around the exploration of a phenomenon. For example, a demo related to the storyline “What is living?” can be used to address the standard about what plants and animals need to survive (K-LS1-1) and set the stage for exploring the standard related to the life cycles of organisms (3-LS1-1).

The learning sequence begins with a modified version of the formative assessment probe “Is It Living?” (see Online Resources). The items found on the justified list of this probe are written on chart paper. After framing the lesson around what it means to be “living,” the teacher asks whether students think each item on the list is living or not. Following this preassessment, the teacher engages the students in reading Zoehfeld and Westcott’s What’s Alive (1995). Appropriate literacy skill development is woven into the use of this book. Further, students are supported in using the book’s ideas to revisit their description of “what is living” and revise it.

The stage is set for the demo. It is described on the Dr. STEM Mom: Living-Nonliving Lab Part 2 page and in more detail in the Glue Monsters - Are They Alive? document (see Online Resources). The demo is framed by a fictional story about a sample from outer space that is being tested for evidence of life. That “sample” is actually Duco cement (ideally kept hidden from students by a cardboard box) that is then released into water in a dish (with the content of the dish ideally projected onto a screen from an overhead projector). Students observe what happens. The sample is then fed some “nutrients” (pepper flakes from a shaker). Again, students observe what happens. After students’ observations have been exhausted, they are asked to make a claim based on evidence as to whether the sample is of a living thing or not. The teacher facilitates a conversation, including having students in reexamine their initial ideas about “what is living.”

To bring closure to this lesson, and to generate formative assessment data, the teacher should encourage students to use what they have learned from the book and the demo to revisit their description of “what is living.” Students should be asked anew whether they think the things on the list are living or not and what changes in their reasoning have happened because of the learning sequence.

Demos Live or Virtual

In times of virtual learning, a demo can always be done live or recorded. There are a variety of free platforms (e.g., Flipgrid) available to use to record yourself performing a demo. Whichever way you choose to deliver your demo and incorporate it into your lesson, we share some basic suggestions to enhance the quality and meaningfulness of your work in Figure 3.  

Figure 3

Questions to reflect on when teaching with a demo.

• Is this an effective method to use to teach the topic/concept?

• Is equipment/material available and ready to use?

• Can I ensure visibility and focus attention?

• Can everyone clearly see what is happening and what I am doing? (Think of the background or what you are wearing so students can see a reaction or color change.)

• Did I practice and rehearse this demo, and am I aware of places in the demo to troubleshoot potential issues?

• Do I have a backup or explanation ready in case it does not work?

• Am I asking questions throughout the demo and explaining what I am doing? Am I summarizing at the end of the demo?

• Can I get a student or two or three involved in helping? Can I ensure good class behavior during the demo?

• Is my workspace clear of everything except what I need to do the demo?

• Am I practicing good safety procedures? (goggles, gloves, apron, etc.)


While young learners are engaged in a teacher demo, they learn more from the step-by-step process of actively observing your actions, attempting to figure out what happened, listening to your thinking, describing the procedure, and explaining the process (Milne and Otieno 2007).  Children may be learning intrinsically while engaging in a demo, not realizing it in the moment, but the impression of the phenomenon occurring before them can be lasting, and as such, an increase in their scientific curiosity may result (Gurel 2016), thereby giving them the efficacy to pursue concepts and investigations further.

We strongly encourage you to strategically embed science demos into your lesson planning. Not just once a quarter, and not just once a unit. Demos should and can become a part of your regular science teaching routine. That may mean every day. By familiarizing yourself with the content you teach, you can identify demos that support your instruction, first allowing activation of your students’ prior knowledge, and then the opportunity to scaffold more. 

Online Resources

Defining Life: Science with Tom:

Delicious Differential Weathering: 

Dr. STEM Mom: Living-Nonliving Lab Part 2:

DUCO 2 Final:

Glue Monsters—Are They Alive?

Information about Duco cement:

Is It Living? formative assessment probe:

Traits of Life from the Exploratorium: 

Christopher Roemmele is an associate professor of Earth and space sciences teaching geology and science education at West Chester University in West Chester, Pennsylvania. Steven Smith is the K–12 outreach coordinator for Purdue University Department of Earth, Atmospheric, and Planetary Sciences in West Lafayette, Indiana. Sarah Nern is the K–12 outreach coordinator for Purdue University Department of Chemistry in West Lafayette, Indiana. Brett Criswell is an assistant professor in the Department of Secondary Education at West Chester University in West Chester, Pennsylvania. Missy Holzer is a science standards specialist at Great Minds PBC in Richmond, Virginia.


Coll, R.K., B. France, and I. Taylor. 2005. The role of models/and analogies in science education: implications from research. International Journal of Science Education 27 (2): 183–198.

Crouch, C., A.P. Fagen, J.P. Callan, and E. Mazur. 2004. Classroom demonstrations: Learning tools or entertainment? American Journal of Physics 72 (6): 835–838.

Francek, M. 2002. Differential weathering. Journal of College Science Teaching 32 (2): 144.

Gurel, D.K. 2016, March. The effect of hands-on science demonstrations on elementary students’ curiosity. In AIP Conference Proceedings (Vol. 1722, No. 1, p. 310005). AIP Publishing LLC.

Milne, C., and T. Otieno. 2007. Understanding engagement: Science demonstrations and emotional energy. Science Education 91 (4): 523–553.

NGSS Lead States. 2013. Next Generation Science Standards: For states, by states. Washington, DC: National Academies Press.

Worth, K. 2010. Science in early childhood classrooms: Content and process. Early Childhood Research & Practice 12: (2).

Zoehfeld, K.W., and N.B. Westcott. 1995. What’s alive? New York: HarperCollins.

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