Chemical and Physical Properties in Baking Chocolate-Chip Cookies

#1: Mix the flour with the sugar in a big bowl.

    

#2: Add brown sugar.

#3: Add vanilla extract.

#4: Crack two large eggs into the bowl.

Step 1-4: Physical Changes

Because the different substances are mixed together, but not chemically combined, steps 1-4 are physical changes.

#5: Mix all the ingredients together with a wooden spoon.

Step 5: Physical Change

Although the ingredients are mixed together and hard to tell apart from one another, a chemical change that alters the chemical makeup of the ingredients has not occurred.

#6: Add two sticks of butter.

#7: Mix the butter in with the other ingredients.

#8: Once the butter has been completely blended in with the original mixture, add chocolate chips.

Steps 6-8: Physical Changes (Still, Madison?  Really?  Is this even a project?)

Again, since the ingredients are merely mixed together, not combined chemically, they go through a physical change.

#9:  Place the cookies on a tray and put them in the oven at 375 degrees.

#10: Let them bake for 7-8 mins.  When they're brown around the edges, take them out and let them cool.

Step 10: CHEMICAL CHANGE (FINALLY)

Baking the cookies is a chemical change because the CO2 causes the dough to rise, and creates the porous texture on the underside of the cookies.