The anniversary of the Metric Conversion Act passed again recently with little notice from most Americans. We buy two-liter bottles of pop, and can look down to see kilometers marked on our speedometers — but the act passed in 1975 calling for the voluntary conversion to the metric system has had little impact on the U.S. University of Northern Iowa math professor Catherine Miller says there was an initial effort in education to make the change, but she says Americans were unwilling to accept the move. She says it shows how much we come to count on the familiar things in our lives.She says there was a resistance to change the English measuring system that had been with us for generations. She says the metric system is a science-based system, but it illustrates how hard it is sometimes to change. Miller says the metric system hasn’t been shunned entirely in the U.S.Miller says U.S. companies involved in foreign trade use the metric system when dealing with other countries that use it. She says those companies use the traditional English within the states and switch between the two depending on who they’re dealing with at the time. While we still measure home runs in feet and buy gas by the gallon, Miller says the metric movement hasn’t lost all its steam.She says in some economic circles there’s still a push. She says the European Union has tried to pressure Great Britain to change to the metric system, but she says there’s not a day-to-day push in our lives to make the switch. Miller says the textbooks of the late 70s and early 80s give a good indication of how the metric movement started, and then stalled in the U.S.