NANO AT HOME: An Experiment That You Can Try

 PLEASE NOTE: The Center for Nano- and Molecular Science and Technology (CNM) at The University of Texas at Austin (UT-Austin) cannot guarantee the accuracy or the safety of these activities.  Some of these activities might pose safety hazards for young children, and all activities should be performed under the supervision of a responsible parent, teacher or adult. The CNM and UT-Austin do not assume any responsibility for these activities or their results.  If you have questions, corrections, or comments please do not hesitate to contact the CNM.

download a pdf for this experiment here 

PB & J Lithography

Many electronic circuits are constructed by depositing or removing material one layer at a time in a carefully controlled sequence. You can replicate this technique, called lithography, by making a peanut butter and jelly sandwich.

Supplies Needed:

slice of bread
peanut butter
jelly
four popsicle sticks

1	Lay down the slice of bread. The bread is the foundation of the structure, called the “substrate.”
2	Lay popsicle stick #1 flat over the bread. This stick acts as a “resist” to keep material from reaching parts of the substrate
3	Use stick #2 to spread peanut butter over the bread with stick #1 on it.
4		Lift stick #1 up off the bread. Notice that there is no peanut butter in the place where stick #1 was located.
5	Lay stick #3 gently over the bread and peanut butter in a different direction than stick #1.
6	Use stick #4 to gently spread jelly over stick #3, the peanut butter and the bread.
7	Lift stick #3 up off the bread. Notice that there is no jelly in the place where stick #3 was located.
8		Now you have created a lithographically patterned piece of bread that has four unique layers: (1) bare bread, (2) peanut butter + bread, (3) jelly + bread, and (4) jelly+ peanut butter + bread.

It took a few steps to generate your patterned PB&J sandwich. In real lithography, hundreds of steps are required to generate complex patterns of layered materials!

 You could make an even more complex lithographic pattern on bread by using more layers, such as colored sugar sprinkles or frosting, or by using more complicated patterns for resists, such as a fork.