Scientific Investigation in Chemistry

1.2 Scientific Investigation in Chemistry
CHEMISTRY • Form 4 • Chapter 1: Introduction to Chemistry

1.2Scientific Investigation in Chemistry

A scientific investigation is a systematic method used by scientists and researchers to solve problems related to science. In chemistry, investigations usually begin with the observation of a phenomenon or problem. Through structured steps—ranging from making observations and forming hypotheses to conducting controlled experiments, interpreting data, and drawing conclusions—scientific methods allow learners to find valid answers to chemical questions, such as how water temperature affects the solubility of salt.

Learning Objectives

  • Design an experiment to test a hypothesis.
  • Investigate through experiment the effect of temperature on the solubility of salt in water using a scientific method.

Steps in a Scientific Method & Experiment 1.1 Setup

Follow the 11-step scientific investigation flow and see how the solubility of salt is tested at different water temperatures.

11 Steps in the Scientific Method

  1. Making observations
  2. Making an inference
  3. Identifying the problem
  4. Making a hypothesis
  5. Identifying the variables
  6. Controlling the variables
  7. Planning an experiment
  8. Collecting data
  9. Interpreting data
  10. Making a conclusion
  11. Preparing a report

Experiment 1.1 Setup

Aim: To study the effect of temperature on the solubility of salt in water.
Manipulated variable: Temperature of water
Responding variable: Solubility of salt in water
Fixed variables: Volume of water, mass of salt, time
Temperatures tested: \(10\text{ }^\circ\text{C}\), \(30\text{ }^\circ\text{C}\), \(80\text{ }^\circ\text{C}\)

Brief Explanation

Understand the scientific method and how it is applied in Experiment 1.1.

A scientific method is a systematic method used by scientists or researchers to solve problems related to science. It involves a sequence of general steps to solve a problem using correct methods.

1. Making Observations

Using senses of sight, hearing, touch, taste, or smell to gather information about an object or a phenomenon taking place.

2. Making an Inference

Using data collection and past experience to make a conclusion and explanation about an event.

3. Identifying the Problem

Asking questions based on the inference made.

4. Making a Hypothesis

Making a general statement about the relationship between a manipulated variable and a responding variable to explain an event or observation. This statement can be tested to prove its validity.

5. Identifying the Variables

Identifying the manipulated variable, responding variable, and fixed variable(s) in an experiment to test the hypothesis that is formed.

6. Controlling the Variables

In an investigation, a variable is manipulated to observe its relationship with the responding variable. Simultaneously, other variables are fixed.

7. Planning an Experiment

Determining the materials and apparatus to be used, procedure of the experiment, method of collecting data, and the ways to analyse and interpret the data.

8. Collecting Data

Making observations or measurements and recording the data systematically.

9. Interpreting Data

Organising and interpreting the data collected. Data can be interpreted through calculations, graphs, or charts to find and determine the relationship between the variables.

10. Making a Conclusion

Making a statement on the results of the experiment on whether the hypothesis made is accepted or rejected.

11. Preparing a Report

Communicating in detail on all aspects of the experiment so that the outcome of the experiment can be shared for the development of chemistry knowledge.

Experiment 1.1 Details
Aim To study the effect of temperature on the solubility of salt in water.
Problem statement Does the temperature of water affect the solubility of salt in water?
Hypothesis The increase in temperature of water will increase the solubility of salt in water.
Manipulated variable Temperature of water
Responding variable Solubility of salt in water
Fixed variables Volume of water, mass of salt, time
Materials Distilled water and salt.
Apparatus \(150\text{ cm}^3\) beaker, \(100\text{ cm}^3\) measuring cylinder, thermometer, electronic scale, glass rod, Bunsen burner, stopwatch, wire gauze, and tripod stand.
Procedure:
  1. Measure \(50\text{ cm}^3\) of distilled water at temperature \(10\text{ }^\circ\text{C}\) with a measuring cylinder and pour it into a beaker.
  2. Add \(40\text{ g}\) of salt into the beaker and stir the solution with a glass rod for 2 minutes.
  3. Observe the solubility of salt in the beaker.
  4. Repeat steps 1 to 3 with distilled water heated at \(30\text{ }^\circ\text{C}\) and \(80\text{ }^\circ\text{C}\).
  5. Record your observations in Table 1.1 (Temperatures: \(10\text{ }^\circ\text{C}\), \(30\text{ }^\circ\text{C}\), \(80\text{ }^\circ\text{C}\)).
Brain Teaser: How can you obtain distilled water at \(10\text{ }^\circ\text{C}\)?

Try to Answer First

Answer mentally, then check the explanation.

1

What is the definition of a hypothesis in a scientific investigation?

Answer: A general statement about the relationship between a manipulated variable and a responding variable to explain an event or observation, which can be tested to prove its validity.
2

In Experiment 1.1, what are the fixed variables kept constant throughout the investigation?

Answer: Volume of water, mass of salt, and stirring time.
3

What is the main purpose of the "Making a conclusion" step in the scientific method?

Answer: To make a statement on the results of the experiment on whether the hypothesis made is accepted or rejected.

Common Mistakes

Avoid these errors when planning and interpreting a scientific investigation.

!
Confusing an inference with a hypothesis: An inference uses past experience and collected data to make an explanation about an event, whereas a hypothesis specifically links a manipulated variable directly to a responding variable so it can be tested experimentally.
!
Swapping manipulated and responding variables: Students often identify the responding variable as the one changed deliberately; the manipulated variable is the condition altered (e.g., temperature of water), while the responding variable is the outcome observed or measured (e.g., solubility of salt).
!
Omitting units or values when detailing fixed variables: In Experiment 1.1, failing to state that the volume of water (\(50\text{ cm}^3\)), mass of salt (\(40\text{ g}\)), and stirring time (\(2\text{ minutes}\)) must remain strictly constant across all temperature trials.

Concept Misunderstandings

Compare each misconception with the correct fact.

Misconception

An experiment is a failure if the results reject the hypothesis.

Correct Fact

In the scientific method, the goal of an experiment is to test the validity of the hypothesis. Making a conclusion involves stating whether the hypothesis is accepted or rejected; rejecting a hypothesis provides valid scientific knowledge and leads to new inquiries.

Misconception

"Controlling the variables" means changing all variables one after another in a single trial.

Correct Fact

Controlling variables means only one variable is manipulated while all other identified variables are kept fixed (constant) simultaneously.

Summary

Key facts to remember.

  • The scientific method is a systematic approach comprising 11 sequential steps: making observations, making an inference, identifying the problem, making a hypothesis, identifying variables, controlling variables, planning an experiment, collecting data, interpreting data, making a conclusion, and preparing a report.
  • In Experiment 1.1, this method is applied to study how water temperature (manipulated variable) influences the solubility of salt (responding variable).
  • The fixed variables are water volume, salt mass, and stirring time.
  • A conclusion states whether the hypothesis is accepted or rejected.

Short Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which of the following is the manipulated variable in Experiment 1.1?

2

What step in the scientific method involves stating whether the hypothesis is accepted or rejected based on experimental results?

B. Fill in the Blanks

3

Making a ________ is formulating a general statement about the relationship between a manipulated variable and a responding variable that can be tested to prove its validity.

4

In Experiment 1.1, the mass of salt added into each beaker of distilled water is ________ g.

C. Match the Scientific Method Step with Its Description

Drag each step on desktop. On mobile, tap a step and then tap the matching box.

Step in Scientific Method

Making observations Making an inference Interpreting data Preparing a report

Description

1Using senses of sight, hearing, touch, taste or smell to gather information
2Using data collection and past experience to make a conclusion and explanation about an event
3Organising data through calculations, graphs or charts to determine relationships
4Communicating in detail on all aspects of the experiment to share findings
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Scientific method Observation Inference Hypothesis Manipulated variable Responding variable Fixed variable Solubility

Scientific Investigation in Chemistry

1.2 Scientific Investigation in Chemistry
CHEMISTRY • Form 4 • Chapter 1: Introduction to Chemistry

1.2Scientific Investigation in Chemistry

A scientific investigation is a systematic method used by scientists and researchers to solve problems related to science. In chemistry, investigations usually begin with the observation of a phenomenon or problem. Through structured steps—ranging from making observations and forming hypotheses to conducting controlled experiments, interpreting data, and drawing conclusions—scientific methods allow learners to find valid answers to chemical questions, such as how water temperature affects the solubility of salt.

Learning Objectives

  • Design an experiment to test a hypothesis.
  • Investigate through experiment the effect of temperature on the solubility of salt in water using a scientific method.

Steps in a Scientific Method & Experiment 1.1 Setup

Follow the 11-step scientific investigation flow and see how the solubility of salt is tested at different water temperatures.

11 Steps in the Scientific Method

  1. Making observations
  2. Making an inference
  3. Identifying the problem
  4. Making a hypothesis
  5. Identifying the variables
  6. Controlling the variables
  7. Planning an experiment
  8. Collecting data
  9. Interpreting data
  10. Making a conclusion
  11. Preparing a report

Experiment 1.1 Setup

Aim: To study the effect of temperature on the solubility of salt in water.
Manipulated variable: Temperature of water
Responding variable: Solubility of salt in water
Fixed variables: Volume of water, mass of salt, time
Temperatures tested: \(10\text{ }^\circ\text{C}\), \(30\text{ }^\circ\text{C}\), \(80\text{ }^\circ\text{C}\)

Brief Explanation

Understand the scientific method and how it is applied in Experiment 1.1.

A scientific method is a systematic method used by scientists or researchers to solve problems related to science. It involves a sequence of general steps to solve a problem using correct methods.

1. Making Observations

Using senses of sight, hearing, touch, taste, or smell to gather information about an object or a phenomenon taking place.

2. Making an Inference

Using data collection and past experience to make a conclusion and explanation about an event.

3. Identifying the Problem

Asking questions based on the inference made.

4. Making a Hypothesis

Making a general statement about the relationship between a manipulated variable and a responding variable to explain an event or observation. This statement can be tested to prove its validity.

5. Identifying the Variables

Identifying the manipulated variable, responding variable, and fixed variable(s) in an experiment to test the hypothesis that is formed.

6. Controlling the Variables

In an investigation, a variable is manipulated to observe its relationship with the responding variable. Simultaneously, other variables are fixed.

7. Planning an Experiment

Determining the materials and apparatus to be used, procedure of the experiment, method of collecting data, and the ways to analyse and interpret the data.

8. Collecting Data

Making observations or measurements and recording the data systematically.

9. Interpreting Data

Organising and interpreting the data collected. Data can be interpreted through calculations, graphs, or charts to find and determine the relationship between the variables.

10. Making a Conclusion

Making a statement on the results of the experiment on whether the hypothesis made is accepted or rejected.

11. Preparing a Report

Communicating in detail on all aspects of the experiment so that the outcome of the experiment can be shared for the development of chemistry knowledge.

Experiment 1.1 Details
Aim To study the effect of temperature on the solubility of salt in water.
Problem statement Does the temperature of water affect the solubility of salt in water?
Hypothesis The increase in temperature of water will increase the solubility of salt in water.
Manipulated variable Temperature of water
Responding variable Solubility of salt in water
Fixed variables Volume of water, mass of salt, time
Materials Distilled water and salt.
Apparatus \(150\text{ cm}^3\) beaker, \(100\text{ cm}^3\) measuring cylinder, thermometer, electronic scale, glass rod, Bunsen burner, stopwatch, wire gauze, and tripod stand.
Procedure:
  1. Measure \(50\text{ cm}^3\) of distilled water at temperature \(10\text{ }^\circ\text{C}\) with a measuring cylinder and pour it into a beaker.
  2. Add \(40\text{ g}\) of salt into the beaker and stir the solution with a glass rod for 2 minutes.
  3. Observe the solubility of salt in the beaker.
  4. Repeat steps 1 to 3 with distilled water heated at \(30\text{ }^\circ\text{C}\) and \(80\text{ }^\circ\text{C}\).
  5. Record your observations in Table 1.1 (Temperatures: \(10\text{ }^\circ\text{C}\), \(30\text{ }^\circ\text{C}\), \(80\text{ }^\circ\text{C}\)).
Brain Teaser: How can you obtain distilled water at \(10\text{ }^\circ\text{C}\)?

Try to Answer First

Answer mentally, then check the explanation.

1

What is the definition of a hypothesis in a scientific investigation?

Answer: A general statement about the relationship between a manipulated variable and a responding variable to explain an event or observation, which can be tested to prove its validity.
2

In Experiment 1.1, what are the fixed variables kept constant throughout the investigation?

Answer: Volume of water, mass of salt, and stirring time.
3

What is the main purpose of the "Making a conclusion" step in the scientific method?

Answer: To make a statement on the results of the experiment on whether the hypothesis made is accepted or rejected.

Common Mistakes

Avoid these errors when planning and interpreting a scientific investigation.

!
Confusing an inference with a hypothesis: An inference uses past experience and collected data to make an explanation about an event, whereas a hypothesis specifically links a manipulated variable directly to a responding variable so it can be tested experimentally.
!
Swapping manipulated and responding variables: Students often identify the responding variable as the one changed deliberately; the manipulated variable is the condition altered (e.g., temperature of water), while the responding variable is the outcome observed or measured (e.g., solubility of salt).
!
Omitting units or values when detailing fixed variables: In Experiment 1.1, failing to state that the volume of water (\(50\text{ cm}^3\)), mass of salt (\(40\text{ g}\)), and stirring time (\(2\text{ minutes}\)) must remain strictly constant across all temperature trials.

Concept Misunderstandings

Compare each misconception with the correct fact.

Misconception

An experiment is a failure if the results reject the hypothesis.

Correct Fact

In the scientific method, the goal of an experiment is to test the validity of the hypothesis. Making a conclusion involves stating whether the hypothesis is accepted or rejected; rejecting a hypothesis provides valid scientific knowledge and leads to new inquiries.

Misconception

"Controlling the variables" means changing all variables one after another in a single trial.

Correct Fact

Controlling variables means only one variable is manipulated while all other identified variables are kept fixed (constant) simultaneously.

Summary

Key facts to remember.

  • The scientific method is a systematic approach comprising 11 sequential steps: making observations, making an inference, identifying the problem, making a hypothesis, identifying variables, controlling variables, planning an experiment, collecting data, interpreting data, making a conclusion, and preparing a report.
  • In Experiment 1.1, this method is applied to study how water temperature (manipulated variable) influences the solubility of salt (responding variable).
  • The fixed variables are water volume, salt mass, and stirring time.
  • A conclusion states whether the hypothesis is accepted or rejected.

Short Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which of the following is the manipulated variable in Experiment 1.1?

2

What step in the scientific method involves stating whether the hypothesis is accepted or rejected based on experimental results?

B. Fill in the Blanks

3

Making a ________ is formulating a general statement about the relationship between a manipulated variable and a responding variable that can be tested to prove its validity.

4

In Experiment 1.1, the mass of salt added into each beaker of distilled water is ________ g.

C. Match the Scientific Method Step with Its Description

Drag each step on desktop. On mobile, tap a step and then tap the matching box.

Step in Scientific Method

Making observations Making an inference Interpreting data Preparing a report

Description

1Using senses of sight, hearing, touch, taste or smell to gather information
2Using data collection and past experience to make a conclusion and explanation about an event
3Organising data through calculations, graphs or charts to determine relationships
4Communicating in detail on all aspects of the experiment to share findings
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Scientific method Observation Inference Hypothesis Manipulated variable Responding variable Fixed variable Solubility