Content Areas: Mathematics (Measurement, Estimation, Number Sense), U.S. History, Science

Context: The proscope can be used to examine daily objects to explore their microscopic properties. US currency is fairly interesting to look at and contains a lot of information. Some of this information is clearly visible but some is indeed difficult to detect with the naked eye. The proscope facilitates discovering these micro objects.

Introduction: U.S. Currency is designed with many subtle "microprinted" objects to deter counterfeiting. These "micro print" patterns are shown here for the One, Five, Ten, and Twenty denominations. Some magnified coins are also included, as well.

Research Questions: When was microprinting developed?___________________________________________

How does it reduce counterfeiting?_______________________________________________________________

Newer Ten Dollar bills have several interesting aspects:

First, look at the bottom left corner on the front of your ten dollar bill. At first glance the "10" appears as if it has lines across it. In reality theses "lines" are rows of the word "ten" up and down the 1 and Zero.

Next, the "tens" also have a unique color and loop pattern on the front of the bill in the bottom right corner.

In addition, the tens also have a string of "micro text" just above the name: Hamilton, printed on the front of the bill.

Proscope Activity: Using your proscope, see if you can find each of these, and search for additional hidden print or objects.

The Five Dollar bill also has some interesting hidden items:

First, examine the left and right borders on the front of the bill. Do you notice anything odd? Try examining these side borders with your ProScope to expose the following repeated pattern.

Next, much like the Ten Dollar bill, the Five also has "micro text" printed near Lincoln's name.

Finally, take a look at the roof of the Lincoln Memorial on the back of the Five Dollar bill.

Several state names are printed there.

Can you find all of them? How many are shown?_________________________________________

Why do you think these are the states listed?_____________________________________________

There are two states listed with names that are different from their current names. List them

___________________________________ & ___________________________________________

Measurment activities: The columns on the Lincoln Memorial are 13 meters tall. Using a \$5 bill determine the following information.

How tall are the columns on the actual bill?_________________________________________________

How tall is the entire Memorial (on the bill)?________________________________________________

Convert this value and determine the height of the entire Memorial in reality?_______________________

This value is in meters, convert it to feet:____________________________________________________

We should look briefly at the One Dollar bill. There are not as extensive measures to prevent counterfeiting these bills but there are still some interesting things to look at.

Number Sense Activity: The base on the pyramid on the reverse has an inscription of Roman numerals on it. What is this number and what does it represent?

________________________________________________________________

The eagle on the back is holding arrows and an olive branch with a symbol above it's head.

Each of these are related; the arrows, the olive branch, and the symbol.
What is the relationship?
________________________________________________________________________
What does the number of items in each set mean?

________________________________________________________________________

Finally, try to examine the Pyramid. Don't examine the eye but rather, how many levels are shown in the base?

__________________________________________________

The Twenty Dollar bill has some interesting embedded objects as well, several are visible to the unaided eye.

First, the back of the 20 has numerous little 20s (watermarks) scattered around the bill. Here are a few.

Also, interesting is the Blueish watermark band that runs along the front of the bill. At first glance, it appears that it is a blue band with "Twenty USA, Twenty USA" running across the right side of the bill. The first sequence appears as though it is a "3-D Block" pattern. Upon further inspection a bit more is revealed (shown here):

Finally, the Twenty Dollar bill also holds a "micro text" imprint similar to the Ten and Five.

Try and find it (it's in a bit different location than the other bills). Where is it located? ________________________

Here is what it looks like.

Other intersting money revelations:

Notice Lincoln sitting at the Lincoln Memorial on a penny.

Measurement Activity: It's kind of difficult to measure the penny effectively. However, we can use the following and the image above to estimate about how tall Lincoln's statue is. Recall that the columns are 13 meters tall. Use this to estimate just how many meters tall the statue of Lincoln sitting at the Memorial really is: (Realize that in the real memorial Lincoln is set further back "inside" the building.

Research: Find out how tall the statue really is once you have estimated it:_________________________

Just for fun: The odd depiction of an eagle landing on Earth's Moon with the Earth in the background on the back of the Susan B. Anthony Dollar coin. I find this odd because the Susan B was issued in 1979, ten years after the first moon landing.

Interesting historical facts associated with bills & coins:

Susan B. Anthony Coin: United States coins are manufactured by the United States Mint, a federal agency of the Department of the Treasury. The mint makes five coins for general circulation-the penny, nickel, dime, quarter, and half-dollar-and each one is engraved with the profile of a president. Between 1979 and 1981, the mint also made a one-dollar coin for general circulation, designed with the profile of women's rights activist Susan B. Anthony, who worked hard to establish Women suffrage.

The Lincoln Memorial: The outside of the building features a series of 36 columns that represent the states in the Union when Lincoln died in 1865. Each column is 13 m high and inscribed with the name of a state. Above these 36 columns are the names of the 48 states of the Union when the memorial was built. The Five Dollar bill represents the front view of the memorial hence the limited number of state names.

Other interesting historical facts can be discovered by researching U.S. Currency (Internet, your money, other sources). Complete the following table with those facts and compare your results to what other people found. An excel table is located [here] to help with space constraints. (MP?) = "does it include microprinting?" The Quarter Dollar is done for you. Hint: Some answers are on this page.

Currency Date Introduced Revisions and Improvements Special Features (MP?) Important Features on the Front Important Features on the Back

Penny

Nickel

Dime

Quarter Dollar

in 1976 celebrated the US Bicentennial. Recent changes are listed to the right No MP, but newer coins showcase the states Remained virtually unchanged since introduction with Washington's Head and the Eagle Newer Quarter Dollar Coins depict each of the United States

Half Dollar

Full Dollar Coin

Susan B. Anthony Dollar Coin

Sacajawea Gold Dollar Coin

\$1 Bill

\$2 Bill

\$5 Bill

\$10 Bill

\$20 Bill

\$50 Bill

\$100 Bill

Suggestions for other explorations:

1. Examine paper currency for additional security measures (interwoven fibers, magnetic strips, etc...)
2. If possible, examine currency from other countries to see if they also incoporate micro objects. Or, it my be helpful to explore how U.S. Currency is evolving with ideas from currency in other nations. These revisions are the offset portraits of faces on the bills, the use of color, watermarking, magnetic strips, etc...