Have them write their definitions on a sheet of paper or share them with the class. Record them on the chalkboard. Discuss characteristics of hazardous substances. For example, most acids are corrosive. They can eat through metal, burn human skin on contact, and give off vapors that burn the eyes.
Acids found in batteries are corrosive.
Toxic poisonous to people and other organisms. Toxic substances can cause illness ranging from severe headaches to cancer and even death if swallowed, and many also can be absorbed through the skin. Pesticides, weed killers, and many household cleaners are toxics. Ignitable capable of bursting into flames. Ignitable substances pose a fire hazard and irritate the skin, eyes, and lungs.