Secret Codes Presented by the MathScience Innovation Center written by Theresa Meade

What is a barcode?

Today’s goals Use math and engineering to: Find out how barcodes work Look at how technology is becoming smaller Propose solutions to a growing problem

Let’s take a look What do you notice about your barcodes? Barcodes

How do they work? How does a scanner “know” that it has read a code correctly? What do all of those numbers mean?

Unlocking the code check digit

Unlocking the code Add the digits in the odd positions =

Unlocking the code = 16 Now multiply your answer by 3. What is 16 X 3?

Unlocking the code Next add all of the even digits except for the last one =

Unlocking the code Now add the results from the odd and even digits: =

Unlocking the code When you add the check digit, your result must be a multiple of 10, otherwise the scanner “knows” there is something wrong with the UPC. So, does give us a multiple of ten?

Your turn! I will hand out student sheets for you to work on. The first two are the same for everyone. You get to choose the next two! Think about ways to make your addition and your multiplication easier. Are there groups that you can put together? Are there facts that you already know?

Let’s talk about your results What strategies did you use to help you check your first barcode?

Let’s talk about your results What strategies did you use to help you check your first barcode? 19 X 3

Let’s talk about your results What strategies did you use to help you check your first barcode?

Were there any other strategies you came up with that were really helpful?

Engineers are still working! This very special device transmits data over radio frequencies. It is more sophisticated and much smaller than today’s barcodes. Why?

PENI-tag

RFID or barcode There are some important differences: RFIDs can be processed hundreds of items at a time, but a barcode scanner can only read one item at a time. RFIDs are much, much smaller than barcodes.

How small is small? Scientists use the metric system. What do you know about this system? Let’s measure some items and put them in order from largest to smallest. I will give you a data sheet and a ruler. Measure each item, and then write its measurement, in order, on your data sheet.

Let’s look at your results What was the length of the longest item you measured? What was the length of the shortest item? Why do you think there were differences in your results? How many centimeters difference between 2 items?

How small is really small? We were just working with centimeters, but our engineers are now working at the “nanoscale”. How many centimeters in a meter? There are one billion nanometers in a meter! How small is that? 100, 0,000,000

Time to investigate! Can you reach the nanoscale? I will give you a 10 centimeter long strip of paper and a pair of scissors. Can you cut your paper into a strip that is 1000 nanometers wide? How many cuts do you think that would be? Keep track of your cuts and let’s see how close you can get to a nanosized piece!

And the point? What did you learn about nanoscale? How difficult do you think it is for our engineers and scientists to work at this level? What benefit do you see for radio frequency identification?

Some examples…

Some examples

RFID

Can you solve this problem? Engineers use math and science to solve problems and design new technologies. How could you improve on barcodes?

Questions?