The Nature of Science strand

Living world

Students explore how evidence can be built by making inferences based on close observations.

Food Webs was developed by the University of Canterbury Science Outreach initiative. It includes a set of vivid photographs selected to illustrate various feeding relationships on Rangatira Island. The supporting notes for NZC Level 5 focus on building conceptual understandings of food webs.

Adapting the resource

The photographs provide opportunities for students to differentiate between observation and inference in scientists’ investigations.

1. Show the students the photograph of several weta on the carcass of a dead bird. In small groups, ask the students to describe what they can see.

In this initial activity discourage students from making inferences – just get them to describe what they can see.

1. Now ask the students what they think is happening in this photograph, and why they think that. Prompt the students to elaborate on their answers, backing up their ideas with evidence. [This could be what they can see in the photo or prior knowledge.]

When answering this question, students are making meaning based on their observations. [They are making inferences based on what they see, in combination with what they already know.]

1. Ask the students how they could check if their inferences are correct. Then discuss how scientists confirm their ideas about feeding relationships, when these are based on their initial observations in an ecosystem.
2. Now select one of the other photographs and display this. [Skink, snipe, black robin, or kakariki could be used for this purpose.] Give the students the information summary for the animal displayed. Ask them to confirm:
   • Which parts of the information, if any, can be confirmed by observing the photograph.
   • Which parts might be supported by further observation and what sort of data would need to be gathered. [For example, watching animal in the act of feeding.]
   • What indirect observations could be used to make inferences about what has been eaten. [For example, analysis of faeces.]

Evidence in science is carefully constructed from observations (direct and indirect) of the natural physical world. Scientists put effort into ensuring they have robust data (i.e., that their observations are accurate). This effort is not usually described when the focus is on the products of scientists’ thinking: students need encouragement and support to pay attention to the meaning-making behind knowledge claims.   

Developing an appreciation of the many ways that data might be gathered and interpreted 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.)

When you ask, “What do you see?” do students limit their answers to things that are observable?

Can they differentiate between what is directly observable and what they already know?

Can they differentiate between the observations they make and the inferences they draw from these?

Can they describe specific investigative processes that might be used to check if inferences are supported by evidence?

For suggestions about adapting tasks in ways that allow students to show progress in gathering and interpreting data see Progressions .

This activity could be a prelude to the construction of a food web as suggested in the resource. Students could follow this up by using any other example of a food web to unpack the nature of the investigative activity (observations and inferences) on which it would be based. The aim is to have them understand that scientific models such as food webs are always careful, evidence-based constructions. They never arrive “ready-made” although that is how students typically encounter them in books and on websites.    

Any clear detailed photographs of interactions in the living world could be used to encourage and practise the skills of close observation and to differentiate between observation and inference.

The Science Learning Hub has a student activity about the Maud Island frog called  Observation: Learning to see .

The capability 4 resource, Bioaccumulation interactive, has a related focus on other types of models as evidence-based constructions.

Counting Kōura (L1 & 2) Connected 1, 2007

Slimes and Oozes (L1 & 2) Making Better Sense of the Material World

Making Puddles(L1 & 2) Connected 1, 2000

The Land Changes: Keeping Earth’s Systems in Balance to Sustain Life (L1 & 2) Building Science Concepts, Booklet 52

“Eureka!”: Accidental Breakthroughs in Science (L3 & 4) Connected 3, 1999

Soil Animals: Diversity beneath Our Feet (L3 & 4) Building Science Concepts, Booklet 6

Weather (L3 & 4) Making Better Sense of Planet Earth and Beyond

Rolling marbles II  (L3 & 4) Assessment Resource Banks

The Noisy Reef: Studying sound under water (L5) Science Learning Hub

Watch This Space (L5) Applications, 2007

Biowaste (L5) QTV archives, Digistore on TKI