Find a suitable mold to create a brain cap. Blow up a latex balloon until it is approximately the same size as your head. This will make a perfect mold for your brain cap.
Make your papier-mache paste in a large bowl. Mix two parts white glue to one part water. Allow the paste to sit for five minutes to thicken.
Tear 1-inch strips of newspaper while the papier-mache paste is thickening. You need enough strips to cover the area of your mold with at least three layers.
Dip a newspaper strip into the papier-mache paste. Cover the strip in paste before removing it. Hold the strip over the bowl to allow excess paste to drip back into the bowl.
Apply the paste-soaked strip to the balloon mold. Continue to apply soaked newspaper strips to the top portion of the balloon. Cover the balloon with three layers of strips. When you are finished, the strips should form a concave oval shape over the balloon.
Place the balloon mold in a safe place. Allow the balloon mold to sit for three days to dry. During this time, do not disturb the mold.
Inspect the mold after three days to see if the papier-mache has dried. Pop the balloon if the papier-mache has completely hardened. Trim the bottom of the mold using scissors. Cut the mold to better form around your head.
Decorate the mold into the brain design that suits your needs. Use paint to color the four lobes of the brain. There is the frontal lobe, located at the front of the brain; temporal lobe, located on the sides; parietal lobe, located at the top; and occipital lobe, located at the rear of the brain. You can also design your mold by the separate cortexes of the brain, which are responsible for the functions of the brain.