Topic 1. Thinking and Working Scientifically

Learning intentions

On completion of this online lesson and this week's lab activities, you will:

Know the definitions of these key science facts:

• Scientific literacy
• Observation
• Inference
• Fair test investigation
• Dependent variable
• Independent variable
• Controlled variables

Be able to perform these key science skills:

• Create testable research questions
• Predict outcomes from a fair test
• Plan a fair test investigation

From lab manual:

• Science is a particular way of looking at the world.
• Scientists use a variety of ways to study the natural (physical and biological) world.
• Science is a body of knowledge, a set of methods/processes and a way of knowing.
• Science inquiry skills include, questioning, predicting, planning, conducting, processing, analysing data and information, evaluating and communicating.
• An essential aspect of communicating scientific understanding is to justify ideas on the basis of evidence, and to evaluate and debate scientific arguments and claims.
• Graphs and tables are a standard means to represent information in science, and a set of conventions is used to enhance communication.
• The information from scientific graphs and tables can be understood at various levels of sophistication.

What is science?

Historian Yuval Harari’s book Sapiens: A Graphic History. The Birth of Humankind, is the graphic adaptation of his bestseller Sapiens: A Brief History of Humankind. In the first couple of pages, he sets the scene for the beginning of human history; the beginning of the universe. The study of the creation of the universe is the study of matter and energy and time, and that is physics. The study of how matter and energy combine to create different structures, like atoms and molecules, is chemistry. On Earth (and perhaps other planets!), particularly complex structures formed and life began. The study of living organisms is biology. We use physics, chemistry and biology to study Earth systems and cycles, and to study other bodies and phenomena in the universe.

In this unit, and in primary schools in Western Australia, students learn physical sciences, chemical sciences, biological sciences, and Earth and space sciences, as well as the nature and development of science, the use and influence of science, and a range of science inquiry skills.

Harari , Y. N. (2020). Sapiens: A Graphic History. The Birth of Humankind. Random House UK, pp. 9-10. Read pages 9-16 here.

What is science?

Science is a body of knowledge and the process for building that knowledge.

Science aims to build increasingly broad and coherent explanations of the natural world.

Science works only with testable ideas.

Scientists test their ideas with evidence from the natural world.

Scientific knowledge is open to questions and revision as new ideas emerge and new evidence is discovered.

Scientists use many different research methods (e.g.. fair test investigations, observational research, comparative research, modelling) to collect data, then they look for patterns in their observations and data.

Scientists are creative, collaborative, and communicate their ideas and findings.

Go to the Western Australian Curriculum for Science and read the first paragraph of the Rationale:

“Science provides an empirical way of answering interesting and important questions about the biological, physical and technological world. The knowledge it produces has proved to be a reliable basis for action in our personal, social and economic lives. Science is a dynamic, collaborative and creative human endeavour arising from our desire to make sense of our world through exploring the unknown, investigating universal mysteries, making predictions and solving problems. Science aims to understand a large number of observations in terms of a much smaller number of broad principles. Science knowledge is contestable and is revised, refined and extended as new evidence arises.”

What is not science?

Science is not a set of established facts and theories to be memorised, so let’s avoid too much ‘ready-made’ science in our classrooms. Focusing on the end products of scientific research, viewed with the benefit of hindsight, misleads students. As science teachers, it is our responsibility to provide children with opportunities to participate in science inquiry, rather than solely its outcomes, and to develop scientific literacy.

Many issues and decisions in today’s world require scientific literacy

To understand a range of issues and make decisions that affect us, we need to be able to critically evaluate which particular scientific knowledge is relevant, the degree to which the knowledge is reliable, and the limitation of this knowledge. In other words, we need to be scientifically literate. Being scientifically literate helps us make informed decisions at a personal, national and global level.

Here are some examples at a personal level:

• Understanding the causes and effects of climate change helps us make decisions about energy use, transportation, and consumption to reduce our carbon footprint.
• Understanding nutritional information and dietary guidelines helps us make choices about diet.
• Understanding how our data are collected, used, and protected online helps us make decisions about which personal information we share, and how we share it.

Skamp, K. & Preston, C. (Eds.) (2021). Teaching Primary Science Constructively (7th ed.), Cengage Australia, p. 9.

Western Australia’s School Curriculum and Standards Authority (SCSA) defines scientific literacy as “an ability to use scientific knowledge, understanding, and inquiry skills to identify questions, acquire new knowledge, explain science phenomena, solve problems and draw evidence-based conclusions in making sense of the world, and to recognise how understandings of the nature, development, use and influence of science help us make responsible decisions and shape our interpretations of information.”

Western Australian Science Curriculum – rationale

Go back to the Western Australian Curriculum for Science and read the next two paragraphs of the rationale, in which SCSA explains how the curriculum helps develop students’ scientific literacy.

“The Western Australian Curriculum: Science provides opportunities for students to develop an understanding of important science concepts and processes, the practices used to develop scientific knowledge, of science's contribution to our culture and society, and its applications in our lives. The curriculum supports students to develop the scientific knowledge, understandings and skills to make informed decisions about local, national and global issues and to participate, if they so wish, in science-related careers.

In addition to its practical applications, learning science is a valuable pursuit in its own right. Students can experience the joy of scientific discovery and nurture their natural curiosity about the world around them. In doing this, they develop critical and creative thinking skills and challenge themselves to identify questions and draw evidence-based conclusions using scientific methods. The wider benefits of this "scientific literacy" are well established, including giving students the capability to investigate the natural world and changes made to it through human activity.” (Emphasis added.)

Western Australian Science Curriculum – aims

There are seven aims of the science curriculum with three (in bold) that relate directly to thinking scientifically. The curriculum aims to ensure that students to develop:

• an interest in science as a means of expanding their curiosity and willingness to explore, ask questions about and speculate on the changing world in which they live
• an understanding of the vision that science provides of the nature of living things, of the Earth and its place in the cosmos, and of the physical and chemical processes that explain the behaviour of all material things
• an understanding of the nature of scientific inquiry and the ability to use a range of scientific inquiry methods, including questioning; planning and conducting experiments and investigations based on ethical principles; collecting and analysing data; evaluating results; and drawing critical, evidence-based conclusions
• an ability to communicate scientific understanding and findings to a range of audiences, to justify ideas on the basis of evidence, and to evaluate and debate scientific arguments and claims
• an ability to solve problems and make informed, evidence-based decisions about current and future applications of science while taking into account ethical and social implications of decisions
• an understanding of historical and cultural contributions to science as well as contemporary science issues and activities and an understanding of the diversity of careers related to science
• a solid foundation of knowledge of the biological, chemical, physical, Earth and space sciences, including being able to select and integrate the scientific knowledge and methods needed to explain and predict phenomena, to apply that understanding to new situations and events, and to appreciate the dynamic nature of science knowledge.

All of these aspects are important, and will be developed in this unit. It is important to specifically highlight the aspect of communicating scientific understanding because this skill is, at times underdeveloped. Furthermore, you will be responsible for helping your students learn to justify ideas on the basis of evidence, and to evaluate and debate scientific arguments and claims. Lab sessions in this unit have been structured to assist you in developing your scientific communication skills through scientific explanation tasks.

What is scientific literacy?

Describe scientific literacy in your own words.

Which of the following is an explanation as to why science is important to us?

(multiple choice question)

Western Australian Science Curriculum – structure

There are three integrated strands in the Western Australian Curriculum: Science: Science Understanding, Science as a Human Endeavour and Science Inquiry Skills. Each strand has its substrands.

Western Australian Science Curriculum – science inquiry skills

In this week's topic, we are focussing on thinking and working scientifically, which relates to the Science Inquiry Skills in the curriculum.

Below is an extract from Western Australian Science Curriculum Scope and Sequence. Briefly scan the Science Inquiry Skills for years pre-primary to 6 now and refer back to the Scope and Sequence document regularly throughout the semester. We will be practising these skills in lab activities and in your fair test investigation assignment.

Scientific inquiry

If you haven't already, please read Sections 3-5, pp. 3, 5-7, in Chapter 1. About Science.

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Other processes that advance science:

• trial and error
• experimenting without guessing
• accidental discovery

"More important than a particular method, the success of science has to do with an attitude common to scientists. This attitude is one of inquiry, experimentation, and humility before the facts" (Hewitt et al, p. 5).

Access the following website for a collection of useful resources that are useful for your learning and perhaps your future teaching:

University of California Museum of Paleontology. (2024). Understanding Science.

One of these resources is the Science Flowchart, which explains the process of scientific inquiry. Move your cursor over each stage in the flowchart on that website to see more detail.

The How Science Works interactive is a journalling tool based on this flowchart that can be used to document and reflect on the scientific inquiry process in our lab activities and in your fair test investigations. You can download the app or use the online version.

Watch this video which explores the process of how science works, using an example from an expedition of the International Ocean Discovery Program.

Fair test investigations

Scientific inquiry takes many different forms. For example, geologists and astronomers conduct observational studies and collect data to answer questions about earthquakes and the composition and lifespan of stars. These observational studies may be the only way to answer research questions in these fields of study because it is impossible to manipulate variables in geology or astronomy.

In other fields, especially in physics and chemistry, we can often investigate by changing variables. Variables are all the factors in an experiment that can change (vary) and which could affect other variables or the results of the experiment.

A fair test investigation is a scientific experiment designed to test a prediction in a way that ensures all variables except the one that is being tested are kept constant or controlled.

These are the three types of variables to consider in a fair test investigation:

Independent variable: This is the variable being tested by the investigator. This is the variable that is deliberately changed. There is only one independent variable in a fair test.

Dependent variable: This is the variable that is affected by the changes in the independent variable. Its value is dependent on the independent variable. There is only one dependent variable in a fair test.

Controlled variables: These are all the variables other than the independent variable that could influence or affect the experiment and as such need to be kept constant.

When gathering data for a fair test, it is important to be confident that we are actually measuring what we want to measure. If we deliberately change more than one variable, we won't know what caused any effects on the dependent variable.

Example

Let’s say we wanted to know how the drop height of a ball affects its rebound height.

The drop height is the independent variable.

The rebound height is the dependent variable.

What if we tested using a tennis ball and a golf ball at different drop heights? We wouldn’t be able to identify what caused the differences in the rebound heights – the drop height or the type of ball. This is why it is important to keep all variables constant except the one independent variable. So, for example, the same type of ball needs to be used if we change the drop height.

Part 2

WA Science Curriculum - Science Inquiry Skills

Review the diagram of the structure of the WA Science Curriculum, and pay particular attention to the Science Inquiry Skills strand and its five substrands:

Judging Standards in Year 6

A year 6 student has demonstrated excellent achievement in Science Inquiry Skills if the student...

"Develops investigable questions and designs well-structured investigations into relationships between variables, specifying in detail how variables will be changed and measured.

Describes safety risks and suggests ways to improve their procedures to minimise risk.

Collects, organises, represents and analyses data to identify relationships, and explains how improvements to their methods would increase the quality and reliability of the data.

Uses a variety of ways to clearly represent and communicate complex ideas, scientific knowledge, methods and findings."

(The judging standards can only be accessed by logging in to the SCSA extranet. If you don't already have extranet access, register now using your Murdoch University email address.)

The laboratory activities and the fair test investigation assessment in this unit have been designed to teach you the science inquiry skills that you will need to know and to teach to primary students.

Fair test investigations

A fair test investigation is a scientific experiment designed to test a prediction in a way that ensures all variables except the one that is being tested are kept constant or controlled.

These are the three types of variables to consider in a fair test investigation:

Independent variable: This is the variable being tested by the investigator. This is the variable that is deliberately changed. There is only one independent variable in a fair test.

Dependent variable: This is the variable that is affected by the changes in the independent variable. Its value is dependent on the independent variable. There is only one dependent variable in a fair test.

Controlled variables: These are all the variables other than the independent variable that could influence or affect the experiment and as such need to be kept constant.

Observations vs inferences

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

We use one or more of the five senses or we use measuring instruments to make observations of objects or phenomena. Observations involve direct interaction with the object or phenomenon. They are objective descriptions of the object or phenomenon and do not include any interpretation or guesses as to causes or meanings.

We often use observations to make inferences. An inference is subjective. It is a conclusion that is based partly on observations, and partly on prior experience or theoretical understanding. It is an 'educated guess'. We make inferences to attempt to explain our observations. Inferences may or may not be the correct explanation.

Example

We can make some observations and inferences about two tennis balls.

Observations: bright green feels smooth and dry easier to squeeze smells fresh and rubbery, with a slight aerosol smell this sound* measures 65 mm in diameter weighs 56 grams	Observations: dull brown-green feels a little fluffy and damp harder to squeeze smells earthy and musty measures 65 mm in diameter weighs 58 grams
Inferences: This ball is new. It is from a can of balls that has just been opened.	Inferences: This ball is old. It is no longer used for playing tennis. It was lost in the wet grass. It has been chewed on by a dog.

*Sound source

Formulating testable questions

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

A fair test investigation question

• is testable, so it can be answered through observation and experimentation.
• asks about a specific relationship between the independent variable and the dependent variable.
• is an open question, not a closed question.

You are advised to use one of the following question structures:

What effect does (the independent variable) have on the (the dependent variable) ?

How does increasing/decreasing/changing (the independent variable) affect (the dependent variable) ?

Examples

These are well-written fair test investigation questions because they are open questions asking about the relationship between the independent variable and the dependent variable:

1. What effect does the drop height of a tennis ball have on its bounce height?
2. How does changing the ground surface affect the bounce height of a dropped tennis ball?

The following examples are not well-written fair test investigation questions:

1. Does the drop height of a tennis ball affect its bounce height? (This is a yes/no, closed question.)
2. What's the best ground surface type to drop a tennis ball onto? (This is a closed, 'best-of' question. The answer would be a one-word answer, e.g., concrete.)

Make a prediction

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Fair test investigation predictions

What do you think the relationship between the independent and dependent variables is? Use your scientific knowledge and your experiences to write the prediction.

It is helpful to use this structure:

If the independent variable increases/decreases/changes then the dependent variable increases/decreases/changes because (brief scientific explanation) .

Example

If the drop height of the ball increases, then the bounce height of the ball will increase. This is because the higher ball starts with more gravitational potential energy (GPE). Because of the law of conservation of energy, the ball starting with more GPE will finish with more GPE, i.e., it bounces higher.

Design and conduct the experiment

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Designing fair test investigations

Recall that there are three types of variables to consider in a fair test investigation:

Independent variable: This is the variable being tested by the investigator. This is the variable that is deliberately changed. There is only one independent variable in a fair test.

Sometimes the independent variable is described, sometimes it is counted and sometimes it is measured.

• If the independent variable is described, then we are working with categorical data, e.g., type of ground surface (carpet, rubber mat, tiles, concrete).
• If the independent variable is counted, then we are working with discrete data, e.g., number of seeds (1, 2, 3, etc).
• If the independent variable is measured, then we are working with continuous data, e.g., volume of vinegar (in millilitres).

Dependent variable: This is the variable that is affected by the changes in the independent variable. Its value is dependent on the independent variable. There is only one dependent variable in a fair test.

The dependent variable is always measured. If not, it is not a fair test.

Controlled variables: These are all the variables other than the independent variable that could influence or affect the experiment and as such need to be kept constant.

There are always many controlled variables in a fair test. Ensure you identify at least five controlled variables when you design a fair test.

In primary schools, some teachers use the mnemonic Cows Moo Softly to help children remember that independent variables Change, dependent variables are always Measured, and everything else is kept the Same.

Example

Some researchers are investigating this question: What effect does the drop height of a ball have on its rebound height?

The researchers are going to deliberately change the drop height of the ball and measure the rebound height each time.

The drop height is the independent variable. The rebound height is the dependent variable.

The following variables will be kept the same. These are the controlled variables.

• the same ball, with the same amount of inflation
• test inside (no wind)
• drop on the same surface
• measure the drop height and the bounce height from the ground to the top of the ball (not centre or bottom)
• the same person will drop the ball (no throwing)
• the same person will measure the drop and bounce heights using the same equipment
• view/record the bounce height from the same position

Reliability and validity of a fair test investigation

The reliability (also called consistency, repeatability, or reproducibility) of the results of an investigation refers to the extent to which the same results can be reproduced in another identical investigation, i.e., asking the same research question, using the same equipment in the same conditions. The results of a fair test investigation are more likely to be reliable if all variables, except the independent variable, that can affect the dependent variable have successfully been controlled and if the data collected are both "accurate" and "precise". (See next page for accuracy and precision.)

The validity of an investigation refers to the appropriateness of the design and execution of the investigation and the data analysis by the researcher in answering the research question.

Example

A researcher asked, “How does increasing the mass of an object affect the time it takes to fall from a constant height?” The researcher dropped a cricket ball (162 g), a beach ball (87 g), and a flat piece of paper (5 g) from a 2 m height. The measurements of drop times were accurate and precise. The results showed the cricket ball hit the ground first, the beach ball hit the ground second and the paper took the longest time. The researcher concluded that objects with more mass fall faster than objects with less mass. However, this was an invalid investigation. The design was flawed – the three objects are different shapes and sizes which means they are affected differently by air resistance when falling. Because the design was invalid, the conclusions were also invalid.

Data collection and analysis

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Before data collection

Primary school students are taught to use the following table format for their fair test investigations. Before conducting the fair test, prepare a blank table in this format.

For example, the researcher has the following blank table written out before collecting any measurements of ball rebound heights.

Data analysis - table

Calculate the average (i.e., the mean) of the 3 trials. Do not imply that your measuring instrument was more precise than it actually was by giving the average more decimal places than your trial measurements.

In this example, the researcher only measured to whole centimetres, so the averages are rounded to whole centimetres.

Data analysis - graph

There are many types of graphs. In this unit, you will learn how to construct and interpret line and column graphs (also referred to as bar graphs).

Read How to construct and use a graph included in the appendices of some Primary Connections booklets, by the Australian Academy of Science (2020). For example, see Appendix 5 of Change Detectives. Refer to it when necessary as you learn to construct and interpret graphs.

Follow the conventions below to create graphs that are correct and appropriate for primary science:

Create the graph by hand. (Don't use Excel or other software.)

If the independent variable is categorical or discrete data, the graph must be a column graph (bar graph).

Only the average trial results are plotted, not the trial results.

The vertical axis starts at zero.

Give the graph a name that links the IV and the DV.

Include arrows on both axes.

The width of each bar is the same.

The width of each gap is the same.

The width of the bars doesn’t have to be the same as the width of the gaps.

The bars may be but don’t have to be coloured.

Make the graph BIG. Use up the whole A4 page. The scale of the horizontal axis doesn’t have to be the same as the scale of the vertical axis.

The independent variable goes on the horizontal axis. Label the axis with the name of the variable. Categorical data don’t have a unit. Don’t also call this axis the -axis.

The dependent variable goes on the vertical axis. Label the axis and write the unit next to the variable name in brackets. Don’t also call this axis the -axis.

If the independent variable is continuous data, then the graph must be a line graph.

Only the average trial results are plotted, not the trial results.

Both axes start at zero.

Give the graph a name that links the IV and the DV.

Include arrows on both axes.

Plot the points and join the points with a line.

Do not extend the line to (0,0).

Do not include a line of best fit.

Make the graph BIG. Use up the whole A4 page. The scale of the horizontal axis doesn’t have to be the same as the scale of the vertical axis.

The independent variable goes on the horizontal axis. Label the axis and next to the the name of the variable, write the unit in brackets. Don’t also call this axis the -axis.

The dependent variable goes on the vertical axis. Label the axis and write the unit next to the variable name in brackets. Don’t also call this axis the -axis.

Measurement error

There is always some error associated with measurements. The sources of error can be the measuring instruments (e.g., a ruler may give a length that is always 5% longer than the actual length); human error (e.g., there is always a reaction time tapping a stopwatch and this varies between individuals); and natural variability in physical and biological processes (e.g., a ball doesn’t follow the same path each time it’s rolled down a ramp.)

Whether it’s a fair test investigation or another type of scientific study, we typically repeat trials to collect at least three measurements for each value or category of independent variable, then we calculate the average result (i.e., the mean).

This average result of several trial measurements is more accurate than one single measurement. Accuracy refers to how close a measurement is to the true value. When collecting real world data, we try to achieve the highest accuracy possible by repeating trials, keeping in mind the time and cost involved in repeating trials too many times.

We also try to achieve the highest precision possible. The precision of a set of measurements refers to how close each measurement is to the other measurements. If we have a poorly made or poorly calibrated measuring instrument, it is possible to be very precise but not very accurate. For example, using scales that always give a mass 5% more than the actual mass, a researcher measured the mass of three different 20c coins. The results were 5.93 g, 5.92 g, and 5.94 g. The true mass of a 20c coin is 5.65 g. The results were precise but inaccurate.  

The target diagrams below help to explain the difference between accuracy and precision. At the centre or ‘bull’s-eye’ of each target is the true value. The ‘hits’ on the target represent measurements taken by a researcher.

accurate and precise	inaccurate but precise	accurate but imprecise	inaccurate and imprecise

Sources of error

Some students are conducting a fair test investigation to answer this question: How does the height from which a ball is dropped affect its maximum bounce height?

Consider the different scenarios A, B, C and D shown in the images below. Each image shows a student measuring the bounce height of the ball in one trial. Each image includes the student, the ball and the instrument used to measure the ball’s height. The dotted line represents the student’s line of sight.

Comment on the following:

1. possible sources of error
2. accuracy of the measurements
3. precision of the measurements

Describe what you would do to improve accuracy and precision when measuring the ball’s bounce height.

A	Factors kept constant in each trial:	Trial 1
B	Factors kept constant in each trial:	Trial 1	Trial 2	Trial 3
	same ball measurement taken as distance between ground and top of ball same horizontal distance between student and ball same horizontal distance between ball and tape measure
C	Factors kept constant in each trial:	Trial 1	Trial 2	Trial 3
	same ball same student same tape measure measurement taken as the distance between ground and centre of ball same horizontal distance between student and ball same horizontal distance between ball and tape measure
D	Factors kept constant in each trial:	Trial 1	Trial 2	Trial 3
	same ball same student same tape measure measurement taken as distance between ground and top of ball same horizontal distance between student and ball same horizontal distance between ball and tape measure

Data collection and analysis

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Scientific explanations

Writing scientific explanations involves following a procedure that requires you to use scientific theory and evidence and to develop scientific inferences. This has been dubbed the Premise – Reasoning – Outcome (PRO) strategy. (See Tang, K. (2015). The PRO instructional strategy in the construction of scientific explanations. Teaching Science, 61(4), 14-21.)

1. Premise: State the relevant scientific theories and concepts.
2. Reasoning: State the observations, data, evidence and reasons.
3. Outcome: State the scientific inference, i.e., the conclusion.

Scientific explanation, example 1

This example is based on the example given by Tang, K. (2015), p. 17.

Why does a solid have both a fixed shape and a fixed volume?

Scientific concept: There are attractive and repulsive forces that hold the molecules in the solid in fixed positions.

Reasons: The strong attractive forces pull the particles towards one another. The repulsive forces push the particles apart when they get too close to one another. Thus, the molecules can only vibrate around their fixed positions, and they are held together in a regular pattern.

Conclusion: Therefore, a solid has a fixed shape and volume.

Image source

Scientific explanation, example 2

A bar magnet was attached to a toy car. Using a second bar magnet, the toy car could be moved forwards and backwards without physically touching the car. How?

Scientific concepts: Magnets have a north pole and a south pole. In a bar magnet, the poles are at the ends. Magnets exert forces on each other. Whether the force is attractive or repulsive depends on the orientation of the magnets’ poles. Like poles repel. Opposite poles attract.

Observations: When the north pole of a bar magnet is placed close to the south pole of the bar magnet attached to the toy car (or south to north), the car moved towards the magnet held close to it. When the north pole of a bar magnet is placed close to the north pole of the bar magnet attached to the toy car (or south to south), the car moves away from the magnet held close to it.

Reasons: The north pole of one magnet is attracted to the south pole of the other magnet, because opposite poles attract. The north pole of one magnet is repelled from the north pole of the other magnet, and the south pole of one magnet is repelled from the south pole of the other magnet because like poles repel.

Outcome: Therefore, the strong attractive and repulsive magnetic forces of the two bar magnets enabled the toy car to be moved without physically touching it.

What are scientific explanations?

Describe scientific explanations in your own words.

Communicate the results

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

When communicating the results of scientific research, we include tables of data and graphs (from step 5), scientific explanations (from step 6), and sometimes scientific models.

(If you haven't already, please read Integrated Science (IS) Section B, Physical and Conceptual Models, pp. 240-243, in Chapter 9. Atoms and the Periodic Table.)

A scientific model is a simplified representation or abstraction of a complex real-world phenomenon or system. It can be a useful tool for understanding and communicating scientific concepts, and sometimes for testing hypotheses.

A physical model replicates an object at a more convenient scale (large or small), e.g., a cut-away model of the Earth to show the layers of the Earth. A conceptual model describes a system and the behaviour of the system, e.g., a weather map showing high and low pressure systems.

image source

image source

When reading the results that other researchers have communicated, keep in mind that graphs, tables and other information highlight what the author chooses to present. Therefore, it can be biased so it is important to think critically to uncover any biases. Critical numeracy in science includes knowing how to locate and understanding the important information in context. For example, when looking at the data in a table, what is the range of the data, i.e., what are the highest and lowest measurements? On a graph, where are the peaks and troughs? Are there any trends in the table or graph and if so, what can you infer about the relationship between the independent and dependent variables?

Which of the following is not part of a graph?

(multiple choice question)

Which of the following statements about graphs and tables is not true?

(multiple choice question)

What are the benefits of using a table to communicate information?

When is a graph useful in communicating information?

Interpret a graph from a practice LANTITE numeracy test

Go to LANTITE Numeracy Test Practise Questions, Complete Test 1.

Question 1 of Complete Test 1 asks you to consider the graph below (sourced from the Australian Bureau of Statistics), which shows the number of jobs and the median income for each job, separated by age and gender.

True or false? The median income for a 45 year old female is between $45 000 and $60 000.

Interpret a graph from a practice LANTITE numeracy test

Describe the trends shown in the graph Number of Jobs and Median Employment Income.

Repeat the experiment and replicate the results

The scientific method:

1. Observe: Make observations directly using the five senses and/or measuring instruments.
2. Question: Formulate the question based on the observations. The question must be specific and testable.
3. Make a prediction (hypothesis): Propose a tentative answer to the question, with an explanation and predicted consequences.
4. Test predictions: Design and conduct experiments to see if the predicted consequences are present.
5. Data collection and analysis: Record data from the experiments and analyse the data.
6. Conclude: Draw conclusions based on the data analysis. If the data support the prediction, it is accepted. If not, reject or modify the prediction.
7. Communicate: Share the results with other scientists and non-scientists.
8. Replicate: The experiment is repeated by the same or other scientists to verify the results.

Our experimental results and conclusions are not valid if they cannot be replicated. When writing about the results of scientific research, we ensure enough detail is included that would allow someone else to conduct exactly the same experiment. They should observe the same phenomena and collect similar data as our own.

Download the document Example of a completed investigation planner. Use this document to become more familiar with how to use the scientific method in a fair test investigation.

Scientific method

Match the action to the step in the scientific method.