Hi Jennifer -- thank you for becoming a professional educator!  The employees and ambassadors at Khan Academy can't wait to help you become an awesome teacher.

I guess that I would view an investigation as the second half of an experiment.  Ideally, an experimenter would want to be as objective as possible about the analysis of the data -- which is sometimes difficult if she is too closely involved with the experiment.  If you're just observing the natural world and/or randomly occurring events, then it's much easier to make objective analysis.

Perhaps you could split your class into two halves and run two separate shoebox experiments.  So half of your class (Group A) would try to put things in boxes that are identifiable through the five senses, then the other half (Group B) would try to do the objective investigation.  At the same time, Group B would do the same for Group A to attempt to investigate.  You'd lead/direct the choices in the first half -- making sure the students are setting up the scenario so that it can be reasonably deduced by the other half.  Then each half is better prepared to do the analysis when the time comes.

Let us know how it goes!

Thanks for the response! Let me put the standard here that I want to address:

SC.7.N.1.3 Distinguish between an experiment (which must involve the identification and control of variables) and other forms of scientific investigation, and explain that not all scientific knowledge is derived from experimentation. 

I just want to make sure I am using the correct language with my students and helping them to form a strong foundation from which to practice science.

I don’t want to call it an “experiment” if it’s not technically one. I can tell them they’re going to develop a procedure for their scientific inquiry or investigation. The standards utilize the language of experimentation and investigation. I feel like this is another sticky term in science similar to theory. A scientific experiment (as a noun) is a very specific thing whereas experimenting (as a verb) can be included in scientific inquiry that doesn’t involve controlled experiments.

Am I on the right track with this? I want to provide them with strong examples. Is there any way this mystery box lab COULD be a “controlled experiment?” What would that look like? What would the variables be?

Thank you to anyone who can help me muster through this.

If it IS an experiment, then what would be the manipulated and responding variables? 

Am I being as clear as mud here? lol

I think you have your distinction between experiment and investigation correct.  Your shoebox lab would definitely be an investigation.  Not being a professional teacher myself, I googled the difference and your understanding is consistent with everything I was reading.

If you measure the temperature of a bowl of water that's set out in the sunlight every 30 minutes from sunrise until sunset, that's an investigation.  If you set out 10 different bowls of water -- some that are sugar solutions, some that are salt solutions, some that are in clear bowls, some that are in white bowls, some that are in black bowls, some that are covered, some that are open, some that are insulated, to test one or more hypotheses about what affects temperature change -- that's an experiment. 

Thank you so much for your research, input, and help! I really appreciate it. I just want to make sure that I am understanding the standards correctly and can correctly present them to the students. 

That was very helpful! I want to point out to students that just because we are collecting data, it doesn't mean we are automatically running an experiment.