Here’s a fun science activity for kids of all ages! What happens when you put a sharp pencil through a baggie filled with water?
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Baggie and Pencil Magic Science Activity
Materials for Baggie and Pencil Magic
- plastic baggie
- sharp pencil
- water
Procedure for Baggie and Pencil Magic
- Fill a baggie about 3/4 of the way full with water and seal it shut.
- Make sure your pencil is sharpened. (The sharper the better!)
- Hold up the baggie with one hand and use the other hand to firmly push the pointy end of the pencil through the side of the bag. Continue pushing it until the point is also coming out the other side of the bag.
- Observe what happens!
Question to Spark More Curiosity & Critical Thinking
Is this what you expected to happen? Why or why not? What do you think will happen when the pencil is pulled out of the baggie?
What’s Going On?
No water spills out the holes because ziploc bags are made of a polymer. Polymers have long chains of molecules that are flexible. When you poke a sharp pencil through the baggie, the pencil slides in between the chain of molecules that make up the polymer. The molecule chains make a seal around the pencil that won’t let the water out.
Want to go even further?
Even more activities to inspire creativity and critical thinking for various ages:
- Can you put more than one pencil through your baggie at a time?
- Try this experiment with other materials.
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Kristina @ SchoolTimeSnippets says
April 20, 2013 at 9:28 amSo neat this worked!! We tried something similar a while back with a balloon, but we couldn’t get it!
Tara from The Magnolia Barn says
April 20, 2013 at 11:28 amThis looks fun…I can’t wait to try this with my daughter!
Sue Cahalane says
April 23, 2013 at 9:29 amThat’s a fun science activity! I love your blog!
✿Sue✿
✿Science for Kids Blog✿
Chelsey says
April 30, 2013 at 9:25 pmThank you so much!! I’m so glad you stopped by~ I am your newest fan! Loving your blog!
Katy says
March 27, 2014 at 3:56 pmwhat other materials do you suggest trying?
Chelsey says
March 27, 2014 at 7:30 pmHi, Katy! We’ve tried wooden bamboo skewers and sticks. It was fun to predict which sticks would work and why and then try them out! Here’s another fun related experiment you could try: Balloon Skewer.
Julie says
April 26, 2013 at 1:04 pmCool experiment and you are so brave to do it in the living room. I think my 9 year old son would squeeze it to see what happens next.
Ticia says
April 27, 2013 at 9:10 amThis is such a fun activity, I’ve been meaning to do it with my kids, maybe we’ll do it this summer when we’re between curriculum.
Chelsey says
April 30, 2013 at 9:14 pmThanks, Ticia! The best thing about this science demo is there is such little prep. It would be really fun to do outside on a warm day. When you pull the pencils out, you’d have a little fountain!
Ashley says
April 28, 2013 at 5:36 amSuper fun experiment! We will have to try it for sure, so I am pinning now! Thanks for sharing at Mom’s Library!
Mary Catherine says
April 28, 2013 at 10:18 amSuch a fun experiment! I know my little boy would looove this, especially the mess made once the pencil gets pulled out. 🙂 Thanks for sharing at Stress-Free Sunday!
Melissa says
April 28, 2013 at 4:16 pmVery cool! I’m definitely saving this for the future.
Tracey@We-Made-That says
April 30, 2013 at 10:28 amThis is so cool! I just love all your science experiments! Thanks for sharing this on We Made That!
Ashley says
April 30, 2013 at 7:55 pmFeatured you on Mom’s Library! Can’t wait to see what you share this week!
Jodi says
April 30, 2013 at 8:20 pmSo cool. I wouldn’t have expected that result. Thanks for the fun idea!
brianna says
March 9, 2014 at 4:25 pmthis was so cool
Anonymous says
February 22, 2016 at 6:35 amVery cool!
Lorin Matthews says
May 6, 2014 at 5:17 pmThe polymer bag doesn’t really “seal” the hole around the pencil. Actually, the water doesn’t leak out because of air pressure. A little water leaks out when you poke the hole in the bag. If the top of the bag is sealed, more air can’t get inside it and as the water level falls a bit, it lowers the pressure of the water inside the bag as the air expands into the new space. At some point, the total pressure of the water and air inside the bag equals the air pressure outside the bag (and surface tension of the water).
A similar experiment can be done with a plastic bottle with a lid. Use a pin to poke 6-8 holes all around the side of the bottle. As long as the lid is on, the holes won’t leak. Have an unsuspecting person unscrew the lid, however … watch out!
Anonymous says
January 12, 2015 at 3:14 amThank you for providing scientific explanation to this experiment!
KristieTurner says
July 17, 2014 at 7:03 pmI tried this experiment today with my summer camp friends from age group 6 year old to 12 year olds. They loved it! We put 10 pencils through the one bag and they were totally amazed that it did not leak.
Chelsey says
July 17, 2014 at 9:28 pmI’m so glad they loved it! I always love seeing kids’ reactions to it! 🙂
Pilar Cajas says
January 21, 2015 at 7:00 pmI like it and easy I will try it. thanks.
April says
December 7, 2015 at 8:20 pmJust discovered your site. When we tried the pencil in the baggie, it actually leaked. I followed the directions exactly and used Ziploc baggies. Not sure why?
spencer says
September 5, 2017 at 2:24 pmdid it in class it was fun