1.1 Asking scientific questions
Summary: Is the temperature of the world rising? Why are the polar ice caps melting see Figure 1? We can ask lots of different questions about the world around us. Some are questions that science can answer. Tags: science oxford-science student-book-7 Created: 2026-05-19 Last Updated: 2026-05-19
After this topic, you will be able to:
- develop an idea into a question that can be investigated
- identify independent, dependent, and control variables
- make a scientific prediction.
Think back
- What name is given to observations and measurements made during an investigation?
- What is a fair test?
- Name some sources of data.
Key idea Scientists ask questions based on their observations (what they see). They make a prediction before carrying out a scientific investigation. In all investigations, there are an independent and a dependent variable, and control variables.
Key words observation, investigation, data, variable, independent variable, dependent variable, control variable, prediction
Is the temperature of the world rising? Why are the polar ice caps melting (see Figure 1**)? We can ask lots of different questions about the world around us. Some are questions that science can answer.**
Figure 1What is causing the polar ice caps to melt?
What is a scientific question?
Scientists make observations of the world around them. They ask questions such as ‘Why is the sky blue?’ or ‘Why do some animals become extinct?’. These are examples of scientific questions because they can be answered through scientific investigations.
Scientific investigations are experiments where you collect data (observations or measurements) to answer your question.
Suggesting ideas
Katie and Rahim are watching a tennis match. Rahim observes (notices) that new tennis balls are taken from a refrigerator during the match. Observations like this can give you ideas that you can scientifically investigate.
Developing ideas into questions
In Figure 2, Katie and Rahim discuss why the new balls are kept in a fridge.
Figure 2Why are the new balls kept in a fridge?
What is a variable?
In science, anything that can change during an investigation is called a variable. There are three types of variable:
- Independent variable: a variable you change in an investigation.
- Dependent variable: a variable that changes when you change the independent variable.
- Control variables: variables you need to keep the same in an investigation.
Katie and Rahim decide they want to investigate if the temperature affects how high a ball bounces. In their experiment, temperature is the independent variable. How high the ball bounces is the dependent variable.
A A scientist investigates how the brightness of a torch affects how far you can see at night. Identify the independent variable.
Working scientifically Imagine that Katie and Rahim decide to investigate whether the size of a ball affects how high it bounces. a) State the dependent and independent variables. b) List all the variables that Katie and Rahim would need to control.
Control variables
The temperature of the ball is not the only thing that might affect how high the ball bounces. Katie and Rahim think about other variables that might affect how high tennis balls bounce:
- the height you drop the ball from
- the surface that you drop it onto
- the size of the ball.
Katie and Rahim need to keep these variables the same during their investigation. This is to make sure that they do not affect how high the ball bounces. These are their control variables.
B Suggest one other control variable in Katie and Rahim’s investigation.
Making a prediction
Scientists often have an idea about what they might expect to happen in an investigation. This is called their prediction. Predictions are not always true, though!
Katie predicts that the higher the temperature of the ball, the higher it will bounce. She can then test these ideas out when she completes her experiment.
Stretch zone
- Copy and complete the sentences. The blank variable is the variable you change. A blank variable should be kept the same during an investigation. The blank variable is the variable which changes when the independent variable changes.
- A student is looking at an ice cube melting. Suggest a scientific question that could be investigated.Explain why this is a question that science can answer.
Stretch zone
- A student investigates how the length of a leaf affects how long it takes to fall from a tree to the ground. Identify the independent variable.Identify the dependent variable.Name three control variables for this investigation.