AKRON -- You don't stop a terrorist on the day of the attack. That's what Dr. David Licate teaches his Homeland Security students at the University of Akron.

You stop a terrorist before the bomb is built.

"There are always signs and signals that are out there that can be detected and that's where you stop a terrorist attack," said Licate, an associate professor of criminal justice, emergency management and Homeland Security.

"These attacks that have been prevented, it's been an aware individual, an aware business owner or an employee that said, 'hey, listen, there's something suspicious here,'" said Licate.

He wants his students and the rest of us to know the compounds, to be "situationally aware" like with traditional crime. If you see something, say something.

"We feel polite, we're very busy," he said. "We don't listen to that little voice in our heads that says there's something odd here."

"How do you know if they're not going to do something?" said student Kayla Grizer, who hopes to work with the FBI one day.

Chemicals like acetone, peroxides and fertilizer, fuels and acids can all be used to build a bomb.

The Department of Homeland Security's Bomb-Making Materials Awareness Program helps private business owners and their employees recognize suspicious behaviors or large amounts of dangerous chemicals. You can learn more about the program here.

Like in Boston, most terrorist bombs are homemade explosives or improvised explosive devices, IEDs. Licate says they provide terrorists the cheapest way to cause major damage.

"You can go onGoogleand type it how to make a bomb and tell you all the steps right there onGoogle. It's all out there on the internet," said Adam Daugherty, who is majoring in homeland security. "It's scary how much is public information and can get out there now."

"They are using the internet. They know where to go to get this information," Licate said of potential terrorists. "It's up to the rest of us to be aware of what to look for so we can identify when someone is in need of assistance, when they are disturbed, and might go ahead and use one of these weapons."

David Coulson, with the Bureau of Alcohol, Tobacco, Firearms and Explosives, says all levels of the law rely on your input.

"In addition, the public is highly encouraged to report to law enforcement any threatening statements or behavior by an individual or group. This would include online and social media which is such an active part of our daily lives today," said Coulson in a written statement.

Coulson said since the inception of the Safe Explosives Act in 2002, ATF agents have seen fewer instances where stolen commercial or military explosives are used in homemade explosives.

They have noticed an uptick in the use of commercial grade fireworks in criminal bombings. But smokeless powder, black powder and black powder substitutes have consistently been the filler of choice, possibly because they are not regulated as explosives.

Licate says he's been teaching homeland security since 9/11/2001, and students have becoming increasingly disconnected to the idea of terrorism in the U.S.

Until this week, that is. "It became real for them."

"There's so many resources available," said Rebecca Wrightsman, an emergency management major. "As we become more educated, the bad people, the terrorists, are becoming more educated on other tactics, so we have to stay up to par."