Beyond the Museum: Tinkering with Scribbling Machines


Lately in the Tinkering Studio we've been thinking about how to translate the work we do in the museum to settings like after school programs and community centers.  Scribbling Machines, which started as a PIE project activity and we've continued to tinker with over the years, seems like a perfect activity to try in these situations.  Building a scribbling machine uses everyday objects in unusual ways to create a tool that draws out the path of vibrations created by an offset motor.  It’s a fun way of playing with a phenomenon we experience every time our cellphones ring (there’s an offset motor in there to make it vibrate, too).   There are tons of variables, such as the placement of the motor on the machine or the length of the weight, which you can experiment with as you build to create infinite combinations and unique drawings.


Setting Up the Space for Building Scribbling Machines

There are a few key things to keep in mind when preparing to do this activity with a group.  You’ll want to set up spaces for materials, building, and testing.  As you set these areas up, consider how they flow and how you can move within the space to go back and forth between trying new materials, building, and testing your changes.

  • Materials: this area is where kids can choose supplies they find inspiring for building their scribbling machines.  Common objects like strawberry baskets, yogurt tubs, and cardboard tubes transform into animated drawing creatures.  Having containers like cardboard boxes or buckets to keep these materials separated helps keep the choices clear.  Smaller containers or cups are helpful for holding materials like batteries, googly eyes, motors, and hot glue sticks.  Restaurant supply stores are a great resource for finding containers that are just the right size for materials like pipe cleaners that work best in tall, skinny containers.  We pay a lot of attention to the materials we select and have found that choice is important, but there is such a thing as too many options.  Try the activity to discover what works well for you.  Once you’ve found a good set of materials, remember that the materials area won’t stay perfectly clean and organized, so having a system with labels for where things go shows that we value the materials we choose and empowers kids to be responsible for the spaces we share.
  • Building: once they’ve chosen an initial set of materials to work with (and they may go back to change these many times as they build) they can bring them a work area to create their scribbling machines.  This area can have tools like tape, scissors, and small screwdrivers for poking holes in glue sticks to experiment with changing the vibration of the motor.  It can be helpful to set up a table or station nearby the main work area for using hot glue or cutting tools like box cutters (these are great tools and can be used by kids of many ages, and it’s important to teach how to use them safely).
  • Testing: scribbling machines move erratically and can jump off a table or work surface before you know it!  We’ve tried testing them many different ways and have found that having some sort of corral can be really helpful.  A hula-hoop placed over a piece of butcher paper on a table makes a great testing area for making a communal drawing.  Placing sheets of paper in the bottom of cardboard boxes (like a cereal box with the front removed) work well for making personal testing areas.  Rolling out large pieces of butcher paper on the floor can also work for testing and making beautiful group drawings.
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Tips for Facilitating Scribbling Machines

Every child you work with will be different, and will have different needs and challenges when you try any activity.  As you facilitate this activity these are things you can ask to encourage testing and deeper exploration.  Each learner will have his or her own path to discovery with scribbling machines and you can choose which of these are most appropriate to the individual’s exploration.  Here are some ideas for ways you can complexify your scribbling machines as you build and some tips for working through tough spots.

Get Stuck

  • Try it out first!  Once you’ve tried a few things, asking questions like these can help you to facilitate exploration.
  • Play with offsetting the weight: Notice what happens when you poke several holes in one glue stick and move it on the motor.  What happens when you change the length of the weight?  What about using different materials to offset the motor?  What happens if you use two offset motors?
  • Experiment with different body configurations: Do markers attached to a strawberry basket draw in the same way as markers attached to a cardboard tube?  How does a motor on the top draw differently than a motor attached to the side?
  • Try making different patterns: Can you make a spiral?  A zig-zag? Dots?  Circles?  Lines?
  • Use many combinations of markers: How many different patterns can you make with one marker?  Can you make two markers make the same pattern?  Experiment with attaching markers directly to the body versus attaching them with a pipe cleaner or steel wire away from the body.
  • Notice movement: does your scribbling machine move quickly or slowly?  Does it make big patterns or small patterns?  Is it balanced or wobbly?  Does it jump or glide?  Try changing how it moves.
  • Play with polarity: The motor will spin in different directions depending on how you connect it to the battery.  What happens when you switch the polarity?



Get Un-Stuck

  • Getting the battery to stay attached to the motor can be a challenge because scribbling machines are wiggly.  We’ve experimented with tape, rubber bands, and even magnets to hold them on.  Thick rubber bands (like the ones you find on broccoli at the grocery store) are one of our favorite methods because they fit perfectly around a AA battery.  It’s easy to slide the wire in when you’re ready to test and pull it out when you’re building.  Magnetic clasps for necklaces twisted onto the ends of the motor wires can also work, but can be expensive.
  • Make sure there is room for the weight to spin without getting caught on your scribbling machine.
  • Check your connections.  The motor may not spin if the wires are not touching the battery on each end.  It’s a good place to start troubleshooting if the motor doesn’t seem to work.  Other things to try are switching to a fresh battery or making sure the wires are still attached to the motor as they can sometimes break.
  • Remember, there’s no one right way to build a scribbling machine.

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Expanding This Activity

You may wish to do variations on this activity over several days or weeks.  Here are some ideas on how you could approach doing this activity over time.

  • Start with a bouncing bug: Before you add markers to your scribbling machines, play with the idea of making a creature that moves or bounces.  It’s a great introduction to making circuits with motors and batteries and creates a foundation for playing with offset motors.  You can experiment with motor placement and different weights to give your bug personality and affect how it moves.
  • Delve into scribbles: Pick an element of the scribbling action and play with variables to change it.
  • Make a light painting machine: Try attaching LEDs illuminated with watch batteries to your scribbling machine and take a photo over a long exposure to trace the path your scribbling machine takes.  This expands on the initial exploration by using new tools and materials to create a different form of art.  You can find more information on light painting here.


Tell us what you’ve tried!  We’re constantly experimenting with these activities and want you to try new things too.  Let us know the discoveries you’ve made, innovations you’ve developed, puzzles you’ve encountered, and more!

For more information, here are links to the PIE Project PDF and the Tinkering Studio website’s Scribbling Machines Activity Page.

Hey Lianna, this is a great post! The AVAM education folks are now doing workshops outside the museum, at a local public library in Baltimore: this post will really help them consider Scribbling machines for one of the workshops. Thanks!

This is a wonderful activity. I plan to use it with my class later this year. Thank you for posting it.

Nice write-up Lianna.

Hi. We love this. Can you tell me the scientific phenomenon (for lack of a better word)at play that makes offsetting an object on the motor make it go rather than piercing an object in the middle of the part of the motor that sticks out? We are using this project for my son's science fair project. Thank you!

Hi Devorah! Great question, and one that proved tricky to answer. We couldn't come to an agreement internally within the Tinkering team, so we turned to our physicist extraordinaire and explainer of all things, Paul Doherty. I'm going to try and paraphrase his explanation without mangling it too badly…

Essentially it comes down to center of mass. When the weight is balanced on the axle of the motor, the center of mass remains stable as the motor spins, because the top and bottom of the weight balance each other out. But with an offset weight the top is heavier, so as the motor spins the center of mass also moves around. In order to lift the weight up, there must be an equal force in the opposite direction, and so the basket is pushed down into the ground, deforming itself and/or the legs, which then spring back and make the whole contraption jump up.

But why does the scribbling machine travel instead of just jumping up and down? Apparently that has to do with a phenomenon called stick-slip effect or phenomenon, where two materials alternately stick to each other and slip (in this case the legs and the surface). This is the same phenomenon that is responsible for the sound of stringed instruments that are bowed, like a violin, or the sound that chalk makes on a blackboard, but at much lower frequency, so it doesn't really make an audible sound.

Hope this helps!

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