Example: The boy hit the ball.Explain that this sentence is written in the active voice because the subject (boy) performed the action (hit the ball). Tell students that the use of the active voice makes the meaning clear for readers, and helps to avoid complicated or wordy sentences. Point out that the active voice is used for most non-scientific writing. Then explain that in a sentence using the passive voice, the subject is acted upon. That is, the subject receives the action expressed by the verb.
Example: The boy was hit by the ball.Explain that this sentence was written in the passive voice because the subject (boy) is being acted upon by something (the ball). Tell students that the passive voice is widely used in the sciences because it highlights the action and what was acted upon rather than who or what performed the action.