When scientists report what they have done, they do it using "passive voice."  The idea behind using passive voice is to make it clear that the experiment is central, and that the scientist is an objective observer of nature.  (There is a philosophical question here.  Is it possible to do an experiment and remain objective?  Let the philosophers debate this, while we chemists get back to work!)  Basically, scientists don't write their descriptions in first person--active voice, the way your English teachers want you to write--but instead rephrase the sentence so that the activity is the central portion of the statement.   Confused?  Don't be!  Once you get going, it's really pretty easy.  Just be careful to keep it out of your essays for English class!

Here are some examples:

•   Active voice:  I wrote an essay.
    Passive voice:  An essay was written.

• Active voice:  I used a triple beam balance to find the mass of the object.
  Passive voice:  A triple beam balance was used to find the mass of the object.

Notice that "I" is the subject in the active voice, and the narrator carried out the action.  In passive voice, there is no mention of the narrator.  What had been the direct object in the active voice sentences becomes the subject of the passive sentence, and use a helper verb  to construct a sentence in past perfect tense.  (Sorry, I just can't help myself when it comes to grammar; my mother was an English teacher.)  For our purposes in writing lab reports, try not to use pronouns. Remember, you're trying to show yourself as an objective observer!

Here are some more examples.
 

• Active:  Elizabeth won the race.
  Passive:  The race was won by Elizabeth.

• Active:  We cut the paper into tiny triangles.
  Passive:  The paper was cut into tiny triangles.

• Active:  We purchased snacks and chips for the party.
  Passive:  Snacks and chips were purchased for the party.
   

1.  The teacher ordered chemicals and lab equipment for the year.
2.  I removed all of my school supplies from my new Winnie the Pooh backpack.
3.  Someone stole a pack of gum from the grocery store.
4.  We sang three songs in choral rehearsal today.
5.  I downloaded 25 MP3 files last month.

Check your answers when you are done.