This fun activity is a great addition to any science themed birthday party. The birthday party guests will be amazed with this leak proof bag experiment. The materials for this activity are inexpensive and readily available. Your birthday party guests will see the magic of science right before their eyes as a bag full of water is pierced with sharp pencils yet doesn’t leak!

Magically pierce a bag of water with pencils at your next magic science themed birthday party.



Gallon size Ziplock freezer bag for each guest – You may choose just to have the birthday boy or girl perform the activity for the party guests as this would require just one freezer bag.

About ten sharpened pencils for each guests. You could purchase pencils that match your science birthday party theme and allow the guests to take them home as goody bag items. For instance, if you are having a magic science themed birthday party, you could purchase pencils with wizards, wands, or any magic related decorations.


Pencil sharpener – You could also get each guest a little pencil sharpener as another goody bag item they can take home.

The amazing leak proof bag is a fun science themed birthday activity.


Make sure the pencils have been sharpened into a nice sharp point.

Find an outside area that can get wet without causing too many problems.

Fill each Ziplock bag with water.

Now have each guest hold the bag securely with one hand and push a pencil through the bag with their other hand.

Instruct the birthday party guests to push the pencil all the way through the other side of the bag so it protrudes from the opposite side.

You can make this a fun science themed birthday party game by challenging the guests to see who can push the most pencils through their bag. You may want to have a small gift that matches the science birthday party theme to award the winner. For example, a small magic gag or trick would be cute for a magic themed science birthday party.

Be sure to remind your guests to perform the amazing leak proof bag trick for their friends and family!