1 What are investigations?
Investigations in science are diverse in nature and purpose. Some are closed with a ‘correct’ answer, while others are open-ended and explorative. Some can be completed in one lesson, whereas others need to be conducted over an extended period of time. They differ in the range of skills required to complete them. Some can be led by the teacher and others can be led by the students themselves.
Common to all investigations is that they start with a period of exploration and subsequently concern a problem or question that needs to be solved or answered. Investigations also involve collecting and analysing evidence in order to answer the question that is being investigated.
Wellington and Ireson (2012) set out a typology of questions for investigations, which is summarised in Table 1.
| Types of question | Examples |
|---|---|
| ‘Which’ | Which bag is strongest? Which fabric is the best insulator? |
| ‘What’ | What happens to the boiling point of water if salt is added? What happens to a compost heap over time? |
| ‘How’ | How does paper change when it is burned? How is solubility affected by temperature? How much fat is in my diet? How does the quality of water in the river change? |
Different types of scientific investigations have been described by Turner (2012). These are summarised in Table 2.
| Types of investigation | Examples |
|---|---|
| Long-term monitoring/observation | How will our compost heap change over time? |
| Identifying and classifying (includes surveys) | How do people vary in height? |
| Pattern seeking | Do taller plants grow from bigger seeds? Why do some objects float? |
| Research (using secondary sources) | How can we tell the time without clocks? |
| Fair testing (controlling variables) | Which is the strongest bag? |
 Pause for thought
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Case Study 1 focuses on how young students can investigate change.
Case Study 1: Experiencing change
Mrs Kama explains how she encouraged her young students to investigate change through the topic of cooking.
I teach 65 Class III students. I was teaching the chapter on cooking. As part of that, I got my students to make roti.
After they had washed their hands, I gave them some flour, salt and oil to mix up. They worked in groups of four to share the mixing. When they all had some dough, I asked them to describe it and whether they would eat it like that. They thought this was very funny.
I asked them what we needed to do to make it into food that they would eat. ‘Cook it!’ they shouted. So later that day, I cooked them. In the next lesson we looked at how the dough had changed, and we tasted them.
This case study shows how change is found in many science topics, and how young students can carry out simple exploratory investigations in a more informal way than would be expected of older students.
Pause for thought
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Although younger students would not be expected to use the terms ‘reversible’ and ‘irreversible’, they will have come across many examples of such changes, including burning, sieving and separating oil from water.
These experiences can be used when students are introduced to reversible and irreversible changes. By building a repertoire of experiences within their minds, the students can more easily move onto learning about the more abstract concepts.
It is important to provide your students with opportunities to investigate reversible and irreversible change more closely. Through investigations, your students will make links to the everyday experiences they have had already and will be more engaged in their learning. If you ask your students to just read about these changes and the new substances that are formed, the ideas will not be as tangible and the learning will not be as meaningful.
Why this approach is important