Why designing experiments is so hard for students & what we can do to help! 9

We’ve all heard all about how inquiry is important in science classrooms.  So why is it so hard to do?  And why are there still so teachers reluctant to do it?  Well, for lots of reasons actually…but this post will just talk about one of them – because it’s really hard to do it AND have students learn science content.

Now before all the comments go flying around contradicting that, just hang on and hear me out.  What I mean is that it’s hard for students to learn about the process of doing science (which includes a lot of things, only one of which is designing experiments) while at the same time learning complex science content.  Not saying you can’t (and shouldn’t) do it.  I do.  I’m just saying we all need to understand WHY it’s so difficult and scaffold students when necessary to get there!

Cognitive Load Theory

John Sweller developed Cognitive Load Theory in the 1980’s and much research has been done on it since then.  If you’re interested, please take the time to look into it what the research can tell you about efficient learning, but I’ll give you a super quick explanation of it.

Stimulus (sight, sound, smell, etc.) must be paid attention to enter our working memory.  People have between 5-9 working memory “slots.”  Once something is in working memory then it activates things related things in our long-term memory (this is where prior knowledge and developing diverse connections to that knowledge come into huge play!)  Once the related long-term memory is activated, it can be used in working memory to process.  Long-term memory is vast…but processing can only occur in the very limited working memory.


There are three types of “load” placed on working memory:

Cognitiveloadtheory2Extraneous load is what we can do without – it’s what we try to limit by writing clear instructions, limiting distractions, and not putting a graph on one page and then having a discussion about it several pages later making the reader flip back and forth (I hate that!).

Intrinsic load is the load placed on our working memory that’s due to the problem or task itself.  You can reduce this by breaking a problem into steps.  This is also reduced as the person develops related long-term schema and chunks together information.  Chunking is taking various pieces of information or tasks become so well practiced and known that it begins to be “chunked” together.

Germane load is the load of learning.  It takes working memory space to learn – to create new schema in long-term memory.

Balancing types of cognitive load

The problem with cognitive load is that it is additive and it must all be taken care of in our limited working memory.  AND, the load of learning (Germane Load), is the last to get taken care of!  So basically, if the total of Extraneous + Intrinsic is equal to or greater than a person’s working memory capacity, then there is no room for Germane load and they won’t learn anything from the experience.  This is when a someone is “cognitively overloaded.”

We’ve all had those moments with our students where we’re working through a problem with them, they’re actively engaged, they’re “with you” every step along the way and you feel like you’re making progress with them – and then you get to the end and they look at you and in all honesty say “I have no idea what we just did and there’s no way I could do it again.”  That’s when they’ve been overloaded and there was no room for them to learn – to develop schema in their long-term memory about what they just did.CognitiveLoadTheory3

So you can help someone that’s been overloaded by lowering Extraneous and/or Intrinsic load.

Lowering Extraneous might mean taking the “story” out of the “story problem” and going back to just plain problems, taking out extraneous information, cutting out that graph and setting it right next to the discussion about it rather than making them flip (with has a technical name called “Split Attention Effect“).

Lowering Intrinsic load might mean breaking the problem into smaller steps, going back and taking time to increase the students’ prior knowledge related to the current goal or scaffolding the student in some way – providing a template, guiding questions, hints, backwards-faded worksheets, reading guides, etc.  Those scaffolds can be “official” – tech tools, worksheets, etc. – or they can be “spur of the moment” guiding questions a teacher asks a student as they struggle with something.

So you’re saying everything has to be simple and striped down?

Nope, not at all!  The world is full of Extraneous Load and students must be able to operate within it.  And the world is full of Intrinsically difficult problems and we need to solve them!  But people can’t learn if they’re cognitively overloaded.  So lower the Extraneous or Intrinsic enough to allow Germane – which leads to them developing schema (“prior knowledge”) – their enhanced schema/prior knowledge now lowers the Intrinsic load of a problem, which means they can tackle something with either higher Extraneous or Intrinsic next time – and this is the “efficient learning loop” that’s the sweet spot of learning!

Of course there’s a catch…

What is good for one students is not necessarily good for all!  What will lower cognitive load for a novice at a specific skill or content might actually INCREASE cognitive load for someone that already has relevant schema developed.  This is called the Expertise-Reversal Effect.  For example, if you have students that struggle with math skills in a chemistry class, Backwards-Faded Worksheets can really help them out and get them to learn the skills much more efficiently.  However, for a student that already has fairly well-developed schema for using those math skills, the scaffolding provided by those worksheets may actually confuse them.  And this is where the fabulous-ness that is differentiation comes into play! :)

So how does this all relate to students designing experiments?

If students do not have well-developed schema for designing an experiment AND they don’t have well-developed schema for the science content involved in the experiment they’re assigned to design, they will most definitely be overloaded!  And this happens much more easily than most of us with these schema developed realize!

Therefore you can either lower the load of the design aspect – by scaffolding or breaking into step-wise pieces – or you can lower the load of the science content.

How much scaffolding a student needs will be a combination of their unique prior knowledge (their schema related to both the design process and the science content involved) and the science content itself.  And it will shift from activity to activity.  A student that feels fairly comfortable with the design process during one activity may be need more scaffolding on that aspect if faced with another activity that really ramps up the science content.

So how can you scaffold students designing their own experiments?

Backwards design! :)

Students are trying to design their experiment in the same order they typically read them in – title, purpose/problem/question, background information and then materials.  But how can they know what materials they need if they haven’t thought about what they’re doing yet (the procedure)?  And how can they design the procedure if they haven’t thought about what data they need?  And how can they know what data they need if they haven’t thought about what format the results will be in to answer/address the purpose/problem/question?

This was the basis of my PhD dissertation (along with the creation of a software tool for students that’s described next) – which if you need to get yourself sleepy you can read it here.  But the short version is that it worked – with an effect size (difference in averages divided by standard deviation) of 1.5 which is a HUGE effect in education! :)

So how can I take this backwards-design scaffolding to the next level?

There’s still a lot extraneous things going on in an experiment design activity even if students are scaffolded in the backwards manner.  That’s why I created the software application during my PhD dissertation.  It combines all sorts of research on how to minimize Split-Attention Effect (like not having a rubric with all the information for the entire lab report on a separate sheet of paper that students have to consult – it’s built into the software and only shows the rubric for the section they’re working on), and lots of research-based tech design about how to design scaffolding tools so that they fade away and guide students through the process itself…maybe I’ll post about all that kind of stuff another time (or you could read about it in my dissertation)

Where can I get this software?

It’s free, and available for Mac and Windows at www.studentdesignedlabs.com

There’s a school named “Test” with a teacher named “Test” with a student named “Test” that all have the password “Test” that you can use to play around with it.  Or you can email me to create your own teacher account and then add whatever student accounts you’d like.

What’s next for this software?

I have a whole list of user-requested upgrades and want to deploy for tablets.  I’d love for you to help out with this project here at my Kickstarter Project.

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9 thoughts on “Why designing experiments is so hard for students & what we can do to help!

  • Reply
    Penny Christensen (@Pen63)

    This is the type of instructional detail which new teachers need in their content area planning meetings. Granted, new teachers must experience a great deal of trial and error on their own, however this should be a consistent ingredient in any common planning sessions through out the academic year for all all educators.

    • Reply
      Kelly Morgan Post author

      Absolutely! I studied a lot of cognition and cognitive load theory in my PhD work and I remembering feeling like it would have been so helpful to have that information when my career began – 8 years earlier! I agree that some things come from trying them and seeing, but if I had at least been shown that you can look at things in this way early on in my training/career, I would have been able to help students learn so much more efficiently and effectively years earlier!

  • Reply
    Gerald Carey

    Hi Kelly and thanks for your website and software.
    Just trying to get my old head around what you are saying.
    I understand (I think) the implications of what you have said up to “So how can you scaffold students designing their own experiments?”
    I have had a go at using your software and from this I can see that each step is broken up into chunks. Before students add information (e.g. the procedure) there is a set of hints and instructions on the right and a marking rubric.
    Your comment about ‘backward design’ has me confused a little. I am a big fan of the Understanding by Design (UbD) approach to curriculum development (amongst other things) which uses a backward design approach.
    Is this the same thing? If so, how would it work in designing a practical?

    • Reply
      Kelly Morgan Post author

      Thanks for your comments! :)

      Yes, the Backwards Design I’m talking about here is similar to that in UbD – the same concept! They start with what the end will look like – what final outcomes and proficiencies do you want – and design instruction to get there. In the Backwards Design I’m talking about (and that’s built into the software), students design their results section (what their final outcome will look like – will it be a calculation, a graph, a comparison, a trend recognition?) and then design a procedure to be able to get to those results.

      Ordinarily, students will try to design a lab in the order they read them in – title, purpose/problem/questions, materials & safety, procedure, data table, results. But they problem they have is that in order to write their own procedure they need to know what data they’re looking for. If the cognitive demand is low (it’s content that they’re very familiar with, such as when a teacher is writing a lab for their students to do), people can hold that information in their head – so it may appear as if a teacher is designing the procedure before the data table & results section – but really they already have those sections planned (at least partially) and they’re holding it in their working memory…they have to…otherwise you’d have NO idea what to put in the procedure if you don’t even know what data or results you’re looking for. Students learning new content can’t hold that information in their working memory – so I have them put it on “paper” (or in the software) so that it then is in “external working memory” – they can refer to it but don’t take up their own working memory slots to keep it there.

      So you’ll see as you go through the software that the first screen asks them to design title, purpose/problem/question, background information and results. Then the second screen removes information they won’t need (the group members and the title) to make room for the new thing they’re designing (the data table). The third screen then removes the background information and makes room for the new section – the procedure. Then the results and data table are removed in the fourth screen and the materials & safety sections are written based on the procedure.
      At that point they can view or print the lab in the “correct” (traditional) order and go perform the experiment. Then they come back to the software to fill in data/observations, complete their results and write a conclusion.

      Hopefully that makes sense…if not, feel free to ask more! :)

  • Reply
    Gerald Carey

    Thanks for your prompt response.
    Despite the timestamp on my post, it’s currently 12:20 pm (on Sunday) here in Australia so I am more used to conducting asynchronous conversations with people in the US and England. Anyway…
    I think what you are saying makes sense but I need to try it with students first (which won’t start for a few weeks yet)
    Have you asked your students why the approached helped to make such an improvement?
    (You are right btw. A 1.5 effect size improvement is really significant!)
    Is there a manual that goes with the software?
    Thanks again for your help. This area of helping students to design and write up practicals has been an interest of mine for years.
    Good to see somebody has taken the time to properly analyse the complexity of what is expected of students.

  • Reply
    Kelly Morgan Post author

    Wow…Australia! :)
    The reasons the students give is that it helps them focus, less clutter (they don’t have the instructions on one sheet, the rubric on another and their work on a third), they know what step to do next, etc.
    There isn’t a manual – I’ll make one after I make the upgrade version as that’s my main push right now…I want to get some upgrades into effect! :) But you can always feel free to ask me any questions.
    Email me with your school name and I’ll create an account for you and then you can create student accounts to use when they return to classes – kellymorganscience@gmail.com

  • Reply
    Alison Maes

    I am very interested in checking out your program. With the advent of NGSS we are working towards more student-designed experiments and I believe your tool could help relieve some anxiety for students and teachers alike. Unfortunately, I am not able to do anything with the program once I have it downloaded. Do I need to have my high school added to the school list?

    • Reply
      Kelly Morgan Post author

      yes, please email me with your high school name and I’ll add your school and create an account for you. Then you add student accounts yourself!


  • Reply

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