The Scientific Method or the Engineering Design Process: How do we know which one to choose?
We will offer some general guidelines at the end of this video, but first we’ll use a
real-world example to compare both.
Let's imagine that we want to watch birds in our backyard to learn more about them.
There are already a few that come to our yard, but we would like to attract more by feeding
them.
How should we approach this project?
Should we use the scientific method or the engineering design process?
Let's go step by step and compare how we could use these two approaches for our project about
feeding birds.
As we go through the steps, you will notice that there are similarities and differences
between the scientific method and the engineering design process.
When using the scientific method, the goal is to understand something about the natural
world and gaining knowledge by asking a question and experimenting to find the answer.
In our bird watching example, the question might be: Which food will attract the most
birds to my yard?
When using the engineering design process, the goal is to solve a problem by building
or improving a product or process.
It starts by defining the problem.
For our bird watching example, the problem statement might be: I need a bird feeder that
attracts more birds to my yard because I want to watch them and learn more about them.
The second step for both the scientific method and the engineering design process is to do
background research.
In our scientific method example, we might research what different types of food birds
eat or what other scientists have found out about birds' food preferences.
In our engineering design process example, our research might focus on finding out how
other engineers have approached building a bird feeder, what challenges they have encountered,
or what types of bird feeders already exist and what types of birds use them.
The next step when using the scientific method is to make a hypothesis or educated guess
about how we think our question will be answered by our experiment.
In our bird watching project, maybe our background research revealed that birds enjoy sweet foods.
We might hypothesize that if we put blueberries, sunflower seeds, a seed mix, and walnuts outside,
then more birds will come to the blueberries than the other foods because they are sweet
and juicy.
When using the engineering design process, we won't make a hypothesis.
Instead, the next step is to specify the criteria or requirements for our product or solution.
When building a bird feeder, for example, we would need to make it big enough and sturdy
enough to hold a certain amount of bird food.
It should be weatherproof, safe for the birds, keep away squirrels, and be relatively inexpensive
and easy to build.
When following the scientific method, we will test our hypothesis by designing and carrying
out an experiment.
To do this we first need to identify the variables of the experiment.
Then, we come up with an experimental procedure that will allow us to collect data about the
birds' food preferences.
For example, we could put out several identical containers that each contain a different type
of food and then collect data about the number of birds that visit each container or record
how quickly the food in each container empties.
When following the engineering design process, we won't do the same kind of experiment.
Instead, we continue brainstorming solutions to our problem, evaluating the different solutions,
and choosing the best one to try first.
For our project, this means we would brainstorm different bird feeder designs and decide which
one we will build first.
In the scientific method, we need to actively ask “is the procedure working” as we experiment
and collect data.
If the experiment is not working, we will need to troubleshoot the procedure and restart
the experiment.
For example, we might find that other animals besides birds eat the food we put out, which
means that we have to re-think our procedure, and then re-do the experiment.
The goal of conducting the experiment is to collect enough data to confidently determine
if our hypothesis is being supported or not.
In the engineering design process, after deciding which bird feeder design we want to try first,
the next step is developing and building a prototype.
This means we use our previous sketches or drawings of the bird feeder we want to build,
choose the materials for each part of the design, and then build our first bird feeder
prototype.
We know we might need to make changes later.
Our prototype is just an initial build that will let us begin testing our product.
In the scientific method, after we finish our procedure and have collected our data,
we review and analyze the data.
This includes making graphs and evaluating if the collected data is complete, of good
enough quality, and is valid.
If our data is sufficient, we can then draw conclusions about whether or not our data
supports our hypothesis.
Sometimes the data leads to more questions and the process starts again with a slightly
different question and a new hypothesis.
The next step in the engineering design process is testing our prototype, which involves measuring
the prototype's performance as well as evaluating it against our design criteria.
For our bird feeder, this means we could observe how well birds interact with our prototype
and keep track of metrics like how many birds visit the feeder, how many eat from the feeder,
whether squirrels get to the food, and whether any parts of the bird feeder get damaged.
If we find that our prototype does not fulfill all of the criteria, we start a new cycle
of brainstorming, improving on our bird feeder design, building, and testing our new prototype.
This type of iteration continues until the design solution meets all requirements.
Iteration is common in engineering.
The last step, for both processes, is communicating our findings.
Sharing our results allows others to use the information we uncovered to continue to discover
more about feeding backyard birds and building the best bird feeder.
Now that we have completed our bird project, we find that we ended up with two different
outcomes based on how we approached the project.
By using the scientific method, we understand which food is best to attract the most birds
and by using the engineering design process, we designed a good bird feeder for our yard.
You might notice that in our example project, the engineering design process and the scientific
method are complementary.
Although the outcomes are different for each process, together they lead to more birds
that we can observe and enjoy.
There are many other problems or projects where science and engineering can be combined.
When you are not sure which process to use for a project, follow these general guidelines:
if you ask: "Why does this happen?" or "What would happen if?" you need to follow the scientific
method.
If you ask "Can I build something that…?" or "Can I build a better something?" you need
to follow the engineering design process.
Thanks for watching and happy creating and experimenting!