Your kids will be amazed when they fill a plastic zip-lock bag with water and poke sharp skewers through, only to find that the bag doesn’t leak!  All you need is a ziplock bag, water and wooden skewers.  (I found this project on the Dragonflytv website! )

Have your child fill a quart-sized ziplock bag with water and seal it.  Let them poke several wooden skewers completely through the bag, from one side to the other, avoiding the part with air in it.  See how many they can push through!  (Remind kids to be careful with the sharp points.)

Ask them why they think it doesn’t leak.  Have them write their hypothesis (theory) down.  You can tell them that the plastic makes a seal around the spot where the skewer is poking through.  The bag is sealed and contains very little air, so there isn’t much air pressure pushing on the water. Now, let your child take the bag to a sink or bathtub and either push a stick through the part of the bag holding air, or remove the stick and they will find that the bag leaks like crazy!   

If they want to, let them draw a picture of what they did or record their results in their science notebook.  Have fun!