Nature of Science · 5 min read
Scientific Inquiry and Investigation
What Is Science?
Science is a way of learning about the natural world. Scientists ask questions, make observations, and conduct experiments to find answers. Science is based on evidence, which means scientists use facts and data to support their ideas.
The natural world includes everything around us that is not made by humans. This includes plants, animals, rocks, water, weather, and outer space. Scientists study all parts of the natural world to understand how things work.
Asking Scientific Questions
Every scientific investigation begins with a question. A good scientific question can be answered through observation or experimentation. Scientific questions are about the natural world and can be tested.
Examples of good scientific questions:
How does the amount of sunlight affect plant growth?
What happens to ice when it is heated?
How does the shape of a bird's beak help it find food?
Making Observations
Observations are information gathered using the five senses: sight, hearing, touch, smell, and taste. Scientists use observations to learn about the world around them.
There are two types of observations:
Quantitative observations use numbers and measurements. Examples include length, mass, temperature, and volume. "The plant is 15 centimeters tall" is a quantitative observation.
Scientists often use tools to make better observations. Microscopes help scientists see very small things. Thermometers measure temperature. Rulers and meter sticks measure length.
Making Inferences
An inference is a conclusion based on observations and prior knowledge. Inferences are not the same as observations. An observation is what you directly see, hear, or measure. An inference is what you think based on your observations.
Forming Hypotheses
A hypothesis is a testable prediction that answers a scientific question. A hypothesis is often written as an "if-then" statement.
A hypothesis is not a guess. It is based on observations and prior knowledge. Scientists test hypotheses through experiments.
Variables in Experiments
A variable is anything that can change in an experiment. There are three types of variables:
Designing a Fair Test
A fair test is an experiment where only one variable is changed at a time. This allows scientists to determine cause and effect. If multiple variables change, scientists cannot know which variable caused the results.
Example of a fair test: A student wants to know if temperature affects how fast sugar dissolves in water. The student uses three cups of water at different temperatures (cold, room temperature, hot). The student adds the same amount of sugar to each cup and stirs the same way. The student times how long it takes for the sugar to dissolve.
In this experiment:
Experimental and Control Groups
In many experiments, scientists use two groups:
By comparing the two groups, the scientist can determine if the plant food made a difference.
Steps of the Scientific Method
The scientific method is a process scientists use to investigate questions. While scientists may not always follow these steps in exact order, the general process includes:
Repeating Experiments
Scientists repeat experiments multiple times to make sure their results are reliable. If an experiment produces the same results each time, scientists have more confidence in their conclusions.
Other scientists also try to replicate experiments. Replication means doing the same experiment to see if the same results occur. If different scientists get the same results, the findings are considered more trustworthy.
Safety in Science
Scientists follow safety rules to protect themselves and others. Important safety practices include:
- Wear safety goggles to protect your eyes
- Wear gloves when handling chemicals or specimens
- Wash hands before and after investigations
- Never taste or directly smell chemicals
- Follow all instructions and report accidents or spills immediately
- Keep the work area clean and handle sharp objects and heat sources carefully
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