Te Kete Ipurangi Navigation:

Te Kete Ipurangi

Te Kete Ipurangi user options:

Symbol key

  • Gather & Interpret dataGather & Interpret data
  • Use evidenceUse evidence
  • Critique evidenceCritique evidence
  • Interpret representationsInterpret representations
  • Engage with scienceEngage with science
  • Understanding about scienceUnderstanding about science
  • Investigating in scienceInvestigating in science
  • Communicating in scienceCommunicating in science
  • Participating and contributingParticipating and contributing
  • Living worldLiving world
  • Material worldMaterial world
  • Physical worldPhysical world
  • Planet Earth and beyondPlanet Earth and beyond

You are here:

Chemical popguns Capability: Use evidence NoS achievement aims: Investigating in science Contextual strands: Material world Level : 1,2,3,4

Chemical Popguns. Making Better Sense of the Material World, page 79.

This resource illustrates how an activity in Making Better Sense of the Material World can be used to provide opportunities for students to strengthen their capability to use evidence to support ideas in the context of science.

Curriculum Aims and AOs

The Nature of Science strand


Achievement objectives relevant to this resource

Investigating in science

Carry out scientific investigations using a variety of approaches: classifying and identifying, pattern seeking, exploring, investigating models, fair testing, making things or developing systems.

L1 & 2:

Extend their experiences and personal explanations of the natural world through exploration, play, asking questions, and discussing simple models.

L3 & 4:

Build on prior experiences, working together to share and examine their own and others’ knowledge. Ask questions, find evidence, explore simple models, and carry out appropriate investigations to develop simple explanations. 

Material World


Achievement objectives relevant to this resource

Properties and changes of matter

Investigate the properties of materials.

L1 & 2:

Observe, describe and compare physical and chemical properties of common materials and changes that occur when materials are mixed, heated, or cooled.

L3 & 4:

Compare physical and chemical changes.

Learning focus

Students use evidence to support their ideas.

Learning activity

Activity 4 on page 79 of Making Better Sense of the Material World provides instructions to make popguns by mixing vinegar and sodium bicarbonate in a bottle. The notes that accompany the activity provide teachers with a brief explanation of the science occurring.

Adapting the resource

At the end of the activity, ask students to explain:

  • why the cork popped out
  • what evidence did they notice that supports their ideas.

If they can give an explanation but cannot back it up with evidence, ask:

  • What evidence would you need to look for?
  • What might you need to do to get that evidence?

What’s important here?

Science is a way of explaining the world. In science, explanations need to be supported by evidence that is based on, or derived from, observations of the natural world.

Developing an appreciation of what counts as evidence in science supports students to become scientifically literate, i.e., to participate as critical, informed, and responsible citizens in a society in which science plays a significant role. (This is the purpose of science in NZC.)

What are we looking for?

Look for clear links between explanations and evidence. 

If students talk about the cork being forced off or if they talk about the pressure in the bottle:

  • Do they link this to how the cork moves? [The cork gets pushed off and it goes a long way.]
  • Can they link the force to the mixture producing gas? [Water doesn’t force the cork off but vinegar and baking soda make an explosion.]

If students talk about a chemical reaction, or the mixture giving off a gas:

  • Can they provide evidence of how they know a gas has been produced? [The vinegar and the baking soda make bubbles. I can hear a fizzing sound. That’s air (gas) coming out.]

If students provide a tentative explanation [I wonder if you put more baking soda in whether it makes a bigger force.]

  • Can they suggest ways to gather more evidence to support their explanation? [We could measure how far the cork goes, then put twice as much baking soda in and measure how far the cork goes again.]

Opportunities to learn at different curriculum levels

For suggestions about adapting tasks in ways that allow students to show progress in using evidence to support ideas see Progressions .

Exploring further

Other activities in the same unit of work (Fizzing and Foaming) in Making Better Sense of the Material World that require building something are suitable contexts for justifying explanations with evidence. They are:

Activity 5: "Hey, Look, the Bubbles Do Push the Boat!”

Activity 7: Make Your Own Fire Extinguisher

Investigation 1: Billowing Balloons

This adaptation could also be applied to any context where students are asked to follow a set of instructions for a science investigation. Engaging in thinking about what happens and providing evidence to support their ideas can greatly enhance a task that is potentially just "hands-on" rather than "minds-on".

Three Assessment Resource Banks resources,  Throwing balloons 2Throwing balloons 3  and  Throwing balloons 4  have a focus on asking students to justify their ideas. They use the Predict, Observe, Explain strategy, which could be left as is or simplified by using the questions described for Chemical Popguns.

Other resources for this capability

Key words

Making Better Sense of the Material World, fizzing and foaming