Milk The Cow STEM Challenge: Can You Mimic Nature?

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At our house it has been all about farm animals latey. So I was happily surprised when I got some materials out for her and it evolved into learning how to milk a cow! She was just 3 at the time so was not overly involved in the design process. However, she did observe how I kept making mistakes as I tried to create the most efficient milking device aka cow udder. She was the one in charge of testing the device and we talked about how good/bad it was. I perfected the design and when I explain it to you you will see just how easy it is!!! But it did take me a couple tries to get the water flowing properly so it’s a great engineering experience for older kids! For younger ones, just being involved in the process and then playing with it will be enough. So keep reading to find out how you can create your own milking device.

milk the cow

STEM Challenge: Can You Mimic Nature?

Mother Nature is the number one designer. With years of evolution behind her she carefully selects what works and what doesn’t. Engineers and scientists often try to replicate nature’s designs to be used in everyday items and processes. This is called Biomimetics and it is so interesting! The most obvious example is flight. Birds inspired inventors to find a way so that we could also cruise the skies. Here you can find some other cool examples. With this in mind, I created a fun activity that can introduce older kids to this concept and that can also be used for play with younger kids. 

Introduction to the Activity

In my case it was easy to get my kid involved. I put a bucket full of water out and told her we were going to learn how to milk a cow. As she is loving farm animals, this was enough to get her curious enough to do the activity. As I worked on the design, she helped me try it out each time and she was happily playing with the water in-between tries. If your kids are older you can challenge them: can you make a device that will replicate “milking a cow” so you can fill up a cup in less than a minute. You can later time them and see who’s design is most efficient and who can “milk” the fastest! At the end of the post you will find more fun ideas to play with your new creation.

Preparation And Design Suggestions

Lay out all the materials and place a bucket full of water for testing out your design. There are different levels of design:

  1. Your kids do all the designing, creating, testing and improvements. This is perfect to give kids a feeling for the engineering design process
  2. You give some tips/suggestions to help with the designing, they create, test and improve by themselves
  3. You give tips and help with the creation, let them test by themselves and suggest improvements

I will now explain materials and preparation starting from level 1. If you want to give it a go without suggestions just check out the materials and then skip to the follow-up games and activities!


  • Balloons
  • Rubber bands
  • Toothpicks
  • Masking tape
  • Funnel
  • Bucket for water

For toddlers you will basically be making the device yourself but can involve them in little tasks like putting the scotch tape on or wrapping the rubber band around. Talk to them about the process and then you can test your device together and redesign if necessary. 


  • You will need to make sure that the connection between balloon and funnel is a sealed as possible to prevent water from leaking
  • The placement of the holes is important! Don’t make random holes in the balloon
  • Learn where to hold the balloon before squeezing to get as much water out as possible

Step-by-Step Milking Device:

Step 1: Using the toothpick, make holes in the balloon. Make the holes at the bottom at the balloon so the water squirts out well enough to keep the flow of water. Make enough holes to keep the water flowing properly. 

Step 2: Insert the funnel into the balloon and make sure to seal it with scotch tape or/and a rubber band. The deeper you insert the funnel into the balloon the better.

Step 3: Fill the funnel with water and learn how to “milk”. Place your hand on the funnel-balloon connection and squeeze down. Is it better to squeeze fast or slow? 

color mixing milk the cow

Follow-up Games and Activities

Here are some fun suggestions of how you can play with your new milking device! These are definitely activities you can do outside when it’s hot and you don’t mind getting a bit wet. It wouldn’t be fun to stay dry anyway 🙂 

  • Milking Race: set up a race to see who can fill up a container faster
  • Timed Milking: can you fill up a cup before the timer runs up?
  • Who can squirt water the farthest: make a line on the floor and see who can reach it
  • Color Mixing: Prepare a color mixing station and experiment
  • Animal Cleaning Station: give all your animals a shower and wash them off (make a competition out of it?)

To finish up you can talk with your kids about their new creation. What could you use your new design for in real-life? From washing the car/dishes with it, giving the dog a bath, painting with it… it could have many applications! Let your kids think of some fun uses that their new invention could have!

milk the cow

So there you go! A fun activity for the whole family that encourages children to think like an engineer. Create and explore through play and most important of all… have fun with it!

Happy STEM learning!

stem challenge milk the cow

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