Chocolate Chip Meringue Cookies

Yes, This Really Is Science!

• Tell your parents this is a very important learning tool.  These are not just cookies, they are an experiment in density, volume, and states of matter!

Adult Supervision Required:

• HOT!

What You Need:

• 2 egg whites
• 1/2 teaspoon vanilla
• 1/2 teaspoon vinegar
• 1/4 cup sugar
• 1/2 cup chocolate chips

Ask Yourself:

• You are about to use an electric beater to mix up those egg whites really, really fast.  What do you think will happen to the egg whites?  Will they look and feel any different when you are done whipping them?

What You Do:

• Warm up the eggs to room temperature
• Preheat the oven to 250 degrees F.
• Cover the cookie sheets with foil, dull side up
• Place the egg whites, vanilla and vinegar in a bowl
• Using a mixer, whip the mixture until it is white and frothy
• Beat in the sugar a little at a time until you have added it all
• Keep whipping until the mixture is stiff and glossy
• Lightly and gently stir in the chocolate chips
• Drop the batter by spoonfuls onto the cookie sheets and bade for about one hour until cookies are lightly browned
• Let them cool before removing from cookie sheets

The Big Science Words:

• By making these cookies you are learning about density and volume, and also about states of matter!
• Density and volume: by whipping, you have changed the egg whites from a liquid to a foam.  You have also expanded them to three times their original size!  This happens because egg whites are mostly protein, which traps air very well.  When you whip them, those protein molecules grab onto the air and trap it, making and holding onto the bubbles.  You have also changed their size, or volume.  They are much bigger now because of all that air.  But, the air bubbles do not make them more dense, or heavy.  That's why these cookies feel so light; they are mostly air!
• States of matter: by cooking the egg whites (or any eggs for that matter) you have changed the liquid egg into a solid.  That's because of the cool properties of the proteins in egg.  Cooking causes those protein molecules to change shape.  They bunch up instead of being loose and stretched out.  That makes them solid!