Introduction: The Scientific Method
This Instructable will walk you through the scientific method.
So what is the scientific method? It is a systematic way of investigating events, gathering new knowledge, and testing if theories are true. It's quite simple. Here it is in steps:
- Make an observation.
- Ask a question.
- Formulate a hypothesis.
- Make a prediction.
- Test your prediction (experiment).
- Repeat your experiment. Revise your hypothesis if needed.
- Share your findings.
Step 1: Make an Observation
Start by making an observation. Look around you. Is there anything that intrigues you or boggles your mind? We live in a complex world with many things happening all around us, and even though we live in a time of information and technology, there are still a myriad of unanswered riddles and unsolved mysteries. You just need to notice them first.
For the purposes of guiding you through the scientific method, we will have an example. Let's say we visited a garden and noticed the gardener watering some plants. There's an observation.
Step 2: Ask a Question
Think about your observation. There's bound to be at least one question from it. Now from our example, you might roll your eyes and think, "Of course plants need water to grow. Everyone already knows that." Forget about what you know for a moment and think. Question everything related to your observation, even the obvious stuff.
Why do plants need water? Does it have to be water? Will other liquids work? What if the water was mixed with something? What if a plant's roots were frozen in ice? Will the plant still grow?
Once you have your questions, do some research before you grab your lab coat. As I've mentioned, we live in a time of information. It is likely that someone else before have asked the same questions and perhaps have answered them for you. Go to the library, ask your teacher, or run some quick searches on the Internet. But even if you find that your question is no longer a mystery, don't let that stop you from finding out the answer on your own. You never know; you might discover something that could debunk centuries-old theories.
Choose just one question from your list. Going back to our example, let's say we wanted to know if plants will still grow if they were watered with other kinds of liquids.
Step 3: Formulate a Hypothesis
Now formulate a hypothesis. A hypothesis is a possible explanation for something. Keep in mind that a hypothesis is not just a random guess.They're often created based on bits of what you already know.
In our example, we were wondering if plants will grow if watered with other kinds of liquids. Maybe we've only ever seen people water plants with just water before, or we noticed that the phrase is "water the plants" and never something else like "milk the plants" or "soda the plants." With our preexisting knowledge, our hypothesis might be something like:
Plants only grow with water.
Or we might think that since water is a liquid, perhaps plants simply need liquids to grow. So our hypothesis could be:
Plants can grow with any liquid.
Don't start worrying about if whether your hypothesis is right or wrong. Your hypothesis is simply a possible explanation and is meant to be tested and proven. At this point, there is no right or wrong.
Step 4: Create a Prediction
Take your hypothesis and make a prediction. Let's suppose your hypothesis is true. What will happen?
In our example, we wanted to know if plants will grow if watered with other kinds of liquids and we hypothesized that plants only grow when watered with water. If that's true, then that means other kinds of liquids will not work. Therefore our prediction is:
If plants only grow when watered with water, then plants will not grow when watered with other kinds of liquids.
Now we need to see if our prediction is correct. To do that, we need to test our hypothesis.
Step 5: Experiment
An experiment is a procedure or a way of testing a hypothesis.
Let's talk about variables. A variable is an element or a quantity that may vary or change. In an experiment, there are two types of variables:
- An independent variable is the variable that is changed by the experimenter. This is to see if it has any effect on the dependent variable.
- A dependent variable is the variable that is to be measured.
In our example, we wanted to know if the kind of liquid used to water a plant has any effect on the plant's growth. The independent variable would then be the kind of liquid used to water the plant. The dependent variable would be the height of the plant. Our hypothesis suggests that plants will not grow if watered with any liquid other than water. In order to check if this is correct, we need to have a set of x plants and water them with x different kinds of liquids.
Let's say we decided to use milk, soda, and fruit juice. So now you have 3 different types of liquids. Each of these will be used to water 3 separate plants to see their effects on the plants' growth. But we will also need a control - this will be our benchmark or standard to which our 3 test plants will be compared to. In this case, our control will be a plant watered with regular water. Our experiment will go like this:
- Get 4 containers and label them "water," "milk," "soda," and "fruit juice."
- Fill each container with the same amount of soil.
- Plant seeds in each container.
- Set the containers in a sunny spot.
- Water the plants with 1/2 cup of their respective liquids every day for the next 7 days.
- Water the plant in the container labelled "water" with 1/2 cup of water.
- Water the plant in the container labelled "milk" with 1/2 cup of milk.
- Water the plant in the container labelled "soda" with 1/2 cup of soda.
- Water the plant in the container labelled "fruit juice" with 1/2 cup of fruit juice.
Make sure you write down every step in detail when you're designing your experiment. You shouldn't have room for mistakes during the experiment as this can affect your results.
Be consistent. You should only change the independent variable and nothing else in the experiment. In our example, the independent variable is the type of liquid and so that's the only thing you should be changing. This means you shouldn't use different types of soil for each seed, place them under varied amounts of sunlight, or use different amounts of liquid used to water them. Everything must be consistent.
Do not perform harmful experiments on animals or people. Don't be evil, please.
Step 6: Revise And/or Repeat
At the end of your experiment, you would have had collected enough data to draw a conclusion from. Do your results satisfy your hypothesis? Was your hypothesis correct or incorrect?
Now if your experiment proves your hypothesis, don't celebrate just yet. You still need to go back and repeat your experiment. Why? You need to make sure that your results are absolute. Your results shouldn't be products of luck or accidents. The more you test, the more solid the confirmation of your hypothesis will be.
Don't be frustrated if you end up having a wrong hypothesis. If that's the case, you need to go back and rethink and revise your hypothesis. With your revised hypothesis, come up with another prediction and test your hypothesis again.
In either scenario, you may have new observations or new questions at the end of your experiment. You know what you have to do now. :)
Step 7: Share Your Discovery
Congratulations! You've learned something new. Perhaps you've discovered something that not many people know about. Perhaps you've rewritten the history of science as we know it. Be sure to share your newfound knowledge with the world. Tell someone about it. Write about it. Make a video about it. Share it with us here on Instructables.
In the words of Margaret Fuller:
If you have knowledge, let others light their candles in it.
And that's a basic walkthrough of the scientific method. I hope that helped you out in some way. I'm certainly looking forward to seeing your experiments here on Instructables.
Good luck and stay curious.