Observation

Question

The trash smells.
Explanation
Decaying biological material causes the trash to smell.
Test (independent variable)
Add food scraps to one trash can along with other materials, such as plastic, cardboard, paper, and tin. To a second trash can, add only non-food materials, such as plastic, cardboard, paper, and tin. Observe the smell of each trash can over a few days.
Prediction (dependent variable)
The trash can with food scraps added to it will smell more than the trash can with non-food materials.
Hypothesis
If decaying matter causes the trash to smell, then removing food scraps from the trash will decrease the odor that it produces.  

Is there a control group and why?

please help

Answer 1

I know it has a control group I just don't know how to explain why

Answer 2

food scraps is the independent variable

odor (stink/smell) is the dependent variable

the control is the can without scraps

Answer 3

thank you

Answer 4

why is the can of scraps the control group?

Answer 5

without*

Answer 6

the trash without the food is the control because nothing is being done to it. you are testing to see if the food makes the trash smell.