Hikes in minimum wage are a source of inflation, just like a hike in gas prices.
Any Minimum Wage sets a floor for prices of goods and services that depend on people receiving wages. Thus, consumer prices must stay the same or increase.
As an exercise in economic cause and effect, have your students plot the # of jobs going to foreign countries vs the price change in the US Minimum Wage by year.
Then have your students try to explain any correlation they see in 1.) the classroom, 2.) to their parents, and 3.) to the local TV station at a school press conference. Tri-Cornered Hats are optional, of course.