## What is a scientific experiment?

A scientific experiment is a special way that scientists try to learn new things about the world around us. It’s like doing an interesting activity that helps us answer our questions.

For example, let’s say we want to know if plants grow better when watered with different liquids. We could set up an experiment where we water one plant with water, another with milk, and another with soda.

We would keep everything else the same between the plants, like the amount of light they get and the type of soil they’re planted in. Then we would see which plant grows the best and compare our results.

By doing this experiment, we can learn about what liquids are best for plants to grow and share our findings with others interested in this topic.

Below is a mindmap of terms associated with experiments and their definitions.

## How to conduct a fair and reliable scientific experiment?

To conduct a fair and reliable scientific experiment, you must ensure that you are testing only one variable at a time and control all the other factors that could affect the results. This way, you can be confident that any differences you observe are due to the variable you are testing.

Here are the steps to conduct a fair and reliable scientific experiment:

• Ask a question: Identify what you want to investigate and develop a question you can answer with an experiment.
• Form a hypothesis: Make an educated guess about what you think the answer to the question might be.
• Design the experiment: Decide what you will test, what you will measure, and how you will measure it. Make sure only to change one variable at a time.
• Analyse the results: Look for patterns or trends in your data and draw conclusions based on your observations.
• Communicate the findings: Share your results with others interested in your topic, and explain how you conducted the experiment and what you learned from it.

## Case Study – Is the following experiment fair?

Peter wanted to conduct an experiment to find out which ball would roll the furthest from the point it touched the foot of the ramp.

Discuss if it is a fair test. If “Yes”, give reasons why you say so. If “No”, discuss how you could change the experiment to make it a fair test.

No, it is not a fair test. This is because there is more than one manipulated variable. All four set-ups have ramps of different heights and balls of different materials. Only one variable should be manipulated. Only one ball of the same material and size should be used with ramps of different heights. Balls of different materials can be used with only one ramp of the same height must be used.