Machines used today require someone to use them that is responsible and uses safety procedures.
Many machines require helmets, glasses, or gloves.
These are used to protect the person from any harm. What other equipment or training do you think someone would need to operate large machinery. Bring in some equipment or have someone who works around machinery come in and talk to the class about safety in a factory or job site. When I did this unit I brought in safety goggles, gloves, a pair of steel toed shoes and signs that said helmets required in this area. Ask the students if they have ever known anyone that was hurt from farm machinery or a factory due to unsafe working conditions.