The walkouts are the latest in a nationwide uproar over teacher pay and resources. Backed by labor unions and often with widespread public support, teachers in West Virginia, Oklahoma and Kentucky also have pressed state lawmakers for more resources. Many have told of working two or even three jobs to make ends meet.
In Arizona, protesters promised to hold a walkout after Republican Gov. Doug Ducey earlier this month revealed his plan to give teachers a 20% pay increase by 2020. Educators and supporters objected, saying that plan does not address raising salaries yearly for teachers. They called on Ducey to stop tax cuts until the state's per-pupil spending meets the national average.
The National Center for Education Statistics lists Arizona's average teacher salary for the 2016-2017 academic year at $47,403 — significantly below the national average of $58,950.
Arizona spends about $3,300 less per pupil than the national average, according to the Arizona Office of the Auditor General.
Lynne McKernan, a seventh-grade writing teacher at Mountain Trail Middle School in Phoenix, said Arizona lawmakers walked out of the Capitol on Friday without speaking to teachers.
"In the middle of a crisis, they chose to adjourn rather than sit down with our representatives who have asked to speak with them for weeks," McKernan said in a telephone interview.
State Supt. of Public Instruction Diane Douglas threatened teachers with censorship and stripping of their certifications. While Douglas threatens to silence them, McKernan said, "We've been out in the streets doing her job."
McKernan has three academic degrees and is paid around $36,000 annually. With little funding for resources, she has worked in classrooms with duct tape on outdated books and peeling mouse pads.
"Other schools have the roof caving in," McKernan said. "We used to catch mice at our school. It was like a hobby: 'How many mice did you catch in your classroom today?'"
Without the proper tools, McKernan buys pens and notebooks for her students. "Teachers in Arizona are the only people who steal supplies from home and take them to work."
Students showed solidarity with the teachers, saying the crumbling infrastructure at some schools distracts them from their studies.
"People call this #RedForEd movement a disruption? Oh really, what's really disruptive is the water from the leaking [ceiling] that's dripping on your desk," tweeted Luis Payan, a freshman at Valley Vista High School in the city of Surprise, outside Phoenix.
Ducey remains focused on getting the state Legislature to pass the 20% raise. Protesters have threatened to continue their walkout until all their demands are met.
"If you get a 20% pay increase and you continue to strike, how do you make sense of that to parents?" Ducey said Thursday in an interview with KTAR 92.3.
The walkout by Arizona teachers, which began Thursday, led hundreds of thousands of students — from Flagstaff to Nogales — to stay home and out of classrooms.
Thousands of educators and supporters marched through downtown Phoenix, from Chase Field to the state Capitol, wearing red T-shirts reading "Arizona educators united."
Protesters carried signs that read, "An investment in education is an investment in our future," "Fund our future" and "The future of AZ is in my classroom."
Meanwhile, in Colorado, an upcoming ballot measure in November could tip the scales in the students' favor.
The "Great Schools, Thriving Communities" measure would increase tax rates for corporations and for people who make more than $150,000 annually.
The money would be used to increase base funding for all students, provide full-day kindergarten and increase funding from the state to local districts for English language classes and special education.
"Colorado schools are severely underfunded right now, and this initiative is a way we can ensure that every student has access to the supports they need for success," Susan Meek, a spokeswoman for Great Education Colorado, said in a statement.
Thousands of teachers and supporters descended on the state Capitol in Denver, where they are protesting the lack of funding for student resources and low teacher salaries. Teachers' average salary in Colorado — $46,506 — is even less than Arizona's, according to the National Center for Education Statistics.
Due to the walkouts, the two largest school districts in the state, in Denver and Jefferson Counties, were closed Thursday and Friday.
In an attempt to curb the teachers' walkout, two Republican state lawmakers — Sen. Bob Gardner and Rep. Paul Lundeen — introduced a bill last week to prohibit teachers from organizing or joining in a strike.
If the bill were to pass, protesting teachers could be penalized with termination of their jobs, six months in jail and a fine — but it is not expected to get through the Democratic-majority Legislature.
The recent uproar over teacher salaries and education funding began in February, when teachers in West Virginia went on a nine-day strike with broad public support. Schools shut down in all of the state's 55 counties. The walkouts ended with teachers receiving a 5% pay raise.
Before signing the pay raise bill, Republican Gov. Jim Justice said: "Our children have suffered enough. We have to return some normalcy to the education process."
Next came Oklahoma, where teachers this month also went on a nine-day strike for higher wages and more funding.
The strike ended with the teachers accepting the $479 million lawmakers originally agreed to for school funding and pay raises — well below the $3.3 billion teachers wanted.
In Kentucky, the Legislature on April 13 overrode a veto by Republican Gov. Matt Bevin to pass tax and budget bills that boost education funding.
Bevin denounced the walkouts, charging that children left unattended by working parents had been harmed.
"I guarantee you somewhere in Kentucky today, a child was sexually assaulted that was left at home because there was nobody there to watch them," Bevin told local reporters. "I guarantee you somewhere today, a child was physically harmed or ingested poison because they were left alone because a single parent didn't have any money to take care of them."
He later apologized for the remarks.