Preschool STEM Activities: Magnets

Children have a natural fascination with magnets. That’s just one reason that we find them in Early Childhood Education (ECE) settings. This activity easily peaks children’s interests, introduces the mysterious world of naturally occurring iron filings, and launches an open-ended investigation! The following can be used as a teaching resource that details several STEM ideas for preschool activities.

Open-Ended Activity/Investigation: Using Cow Magnets and Iron Filings

Recommended Tools:

  • several cow magnets
  • collecting jars or trays
  • Sand or dirt collected from outdoors. (Note: Some areas in the US dont have iron in the soil or sand, please check to make sure before you introduce this project to your kids! If  you dont have iron, give us a call at 720-340-2704 and we can send you some iron-rich Colorado sand!)

Starting your Investigation:

Iron filings have incredibly interesting properties that take on unique shapes as they react with magnets. Iron filings can look like crystals, hair, or even fuzzy bugs to children.  Cow magnets are just the right size and shape to make collecting iron filings easy for young children. Invite them to explore your outdoor space, sandbox, or different trays of natural materials that you've provided in the classroom with their cow magnets. As they collect the filings, combine them with your existing collection of magnets for future play and investigation of magnetism.

Cow Magnets and Iron Filings: STEM Activities for Preschool

"I wonder what would happen if we took these magnets out in the sandbox?" is how one of our teachers introduced this activity to the children. It was quickly obvious that the magnets collected something!

"What is that and I wonder why it sticks to the magnet?!" was the statement that peaked the children's curiosity and focus on the iron fillings.

"I bet we can get rid of some of this sand. you think we can sort the filling out of the sand somehow?" This question launched an experimentation phase of pulling the iron fillings out of the collected sand/iron mix (shown in the photo on the right).

"Let's use these for something curious!" the teacher exclaimed, which led to all sorts of craziness with jars, clear acrylic boards and little sculptures of iron!

Fun Fact: Why is it called a cow magnet? Cow magnets are fed to cows and reside in the cow’s first stomach for the life of the cow. There they trap “tramp iron” which cows naturally ingest as they graze. Sounds crazy, but it’s absolutely true! Just ask a farmer or rancher!

Children can have a hard time identifying what is metal and what is not. Metal can look like plastic and vise versa, which can be confusing. Invite them to explore the properties of magnetism in the following ways:

  • Show them unpainted metal objects (such as a spoon) and painted metal objects (perhaps a table leg).
  • Help children identify the similarities between the painted and unpainted objects, weight, hardness, sound.  Compare the similarities you find in metal to plastic and wood and note the differences.

Exploring ferrous versus non-ferrous materials:

  • Once children know what is metal and what is not, they can test which objects are ferrous using their magnets. Also note the difference between ferrous metal (sticks to a magnet) and non-ferrous metal (like aluminum which does not stick to a magnet).
  • Of course, magnetism is a big concept and can take several weeks to grasp. So if the kids just move about your space testing everything, encourage it! They are experimenting, hypothesizing, reasoning, and analyzing. In other words, they are enjoying fun STEM activities and learning through open-ended investigative play!

What other ways can you encourage exploration of magnetism with your children? Let us know in the comments below!


Questions children (and grown ups!) commonly ask:

Playing with Cow MagnetsWhat are iron filings?

Iron filings are very small pieces of metal. They occur naturally in rock and can be found in sand and dirt. Filings also come off of machinery like dump trucks, car brakes, and grinding wheels.


Why do iron filings stick to cow magnets?

Iron is a ferrous metal, meaning it is attracted or pulled to magnets. You can find filings in many play sands and dirt, depending where you are in the country. The sand needs to be dry and soft so the magnet and filings move freely. Grab your magnet and slide it through the sand back and forth.Take a close look, anything stuck to the magnet? What sticks is ferrous and is most likely an iron filing! Once the magnet is filled with filings, use your hand to slide the filings toward the end of the magnet and pull them off into a container.


If you provide a few Discovery Boards or clear acrylic trays, plastic jars and a little classroom space, then your children might explore and...

  • Sculpt with the iron filings. Pour them onto a magnet from several inches above to sculpt a creation.
  • Pour filings on top of a Discovery Boardor clear acrylic tray. Place a magnet under the board and see how they move around!
  • Grab 2 magnets and pull filings between them.
  • Run the filings up the inside wall of a jar with the magnet on the outside.  

Further the sensory experience with a bit of early childhood chemistry….  

  • Scatter the filings out on a table and let the children collect them all. Add water and then later, add cornstarch - wow!  What a great way to extend this open-ended inquiry!  
  • Remember those little Fuzzy Face novelty toys; plastic cases featuring a bald-headed drawing of a man’s face? The case was filled with bits of iron and came with a magnetic wand so you could add hair, a moustache, or a beard to the face. How about making some of those toys homemade? Ask the children to brainstorm ways to build one or more for your classroom science center. Yes, we said ask the children, and no, we’re not going to give you instructions because we know with just a little guidance from you, your children will design/invent/build something great! Share your young engineers’ designs with us! You can comment on this blog or share with us on Facebook, Instagram, and Twitter!


When assessing, planning, and extending investigations of magnets and magnetism, look to the following:

DAP Guidelines

1B, 2E1, 2E3, 2E4, 2F1, 2F2, 2F3, 2F5, 2G, 3D1, 3D2, 3D3, 4D

NGSS Crosscutting Concepts

  • Patterns

  • Cause and Effect

  • Energy and Matter
    Scale

  • Stability and Change