Don’t you love when science seems like combination of a magic trick and a riddle? Today’s STEM challenge will answer the question, “can you step through an index card?” SPOILER ALERT: the answer is a resounding YES!!! The big question though is HOW can you fit inside of an index card? If your kids get excited by necklaces, another spin on this STEM challenge is to ask, “how do you cut an index card into a necklace?”
Science Virtual Camp
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- How to Make a Lava Lamp (5 different ways!)
- Free Coding Programs for Kids
- Make Your Drawings FLOAT (and the amazing science behind it!)
- FUN Chemistry for Kids

STEM Challenge: Can you step through an index card?
You don’t need too many things for this STEM challenge. The main item is a 3″ by 5″ index card, however, you can even cut out a 3″ x 5″ piece of paper in a pinch. Just keep in mind that thicker paper (like construction paper or cardstock) is less likely to rip when your child steps into it!
STEM Challenge Materials
Gather the following items!
- a 3″ x 5″ index card
- kid-friendly scissors (these are my FAVORITE because they work for both right and left handed children!)

STEM Challenge Directions
Hand your children one index card (or 3″ x 5″ piece of paper) and ask if they think they can step through the card. Or in other words, can they fit their entire body through the card?
If they look at you with a blank stare, offer up a pair of scissors! Ask them if they can cut the index card in a way to make it possible?
My son (who is in Kindergarten) took on the challenge by cutting a big hole in the center. He tried hard to squeeze himself through the hole, but clearly that didn’t work.

He even tried to “just” put his forehead through to no avail.

How to fold the index card
After a few more minutes of struggling to figure out a solution, my kids were convinced that it is impossible. At that point, I pulled out a fresh index card, and showed them how it is done! First, fold one long side of your index card to the other long side, as shown in the picture below.

How to cut the index card
Then cut small slits from the folded side of the paper to about 1-2 cm from the other side. Do NOT cut through completely, or you will have to start over again.

Make the next slices in-between the other cuts on the index card
Next, cut small slits from the non-folded side of the paper to about 1-2 cm from the folded side. Make each of these cuts in between the cuts that you already made in the previous step. Again, make sure not to cut through to the other side, or you will have to start over. You will end up with a paper that looks like the photo below.

Cut the center fold (but NOT the section on either end)
Now, carefully open up the index card and cut the MIDDLE portion of the center fold. Make sure NOT to cut through on either end, because you will break the loop if you do that. You should end up with a paper that looks like the following picture.

Get ready for the science & math magic!
Finally, open up the index card and reveal how it has turned into a huge loop that your children can step through!

How do you cut an index card into a necklace?
My oldest daughter is eight years old, and she had no problems stepping through the index card. However, if you have an older or larger child who cannot fit through the loop, do not despair! Even an adult can fit the index card around their head to wear it as a necklace. So you can do the exact same steps as above, but ask your child “how do you cut an index card into a necklace,” instead of “can you step through an index card?”

How can you fit in an index card? – Science Explained
Why does this STEM challenge work? Even though an index card is only 3″ by 5″, it has a surface area of 15 square inches! You calculate the area of a rectangle by multiplying the length of one side by the length of the other side, which in this case would by 5 x 3 = 15 square inches. By cutting the index card in the special method above, we are redistributing the surface area into a long ring, rather than a solid rectangle. The more cuts you make, the longer the loop will be, which leads us to some fun extensions to do next!

STEM Challenge Extensions
Now that your kids are amazed by how cool math can be, let’s ask some more questions, form some hypotheses, and then run more experiments to get answers!
- What can you do to make your ring longer?
- Measure the widest part of your body and try to figure out the size of the smallest piece of paper that you can cut and step through.
- Does the length of the paper ring change if you fold the short ends of the index card together before cutting it, rather than the long ends? If so, how much longer or shorter is the resulting ring?
- How does making the cuts in the card closer or further away from each other impact the resulting paper ring’s length?
- What about if you make the cuts only half way through, rather than until you get to 1-2 cm from the other side?
Can you step through an index card? Results!!!
Don’t forget to join our Facebook Group and follow us on Pinterest, so you that you won’t miss any of our fun kids activities! We would LOVE to see photos and videos of your index card STEM challenge projects too! Please post your photos and videos in our Facebook Group to show off your amazing work.

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