Science Buddies: "Ask an Expert"

My daughter and your science fair partner are getting ready to start the experiment for "Are there bugs under our feet," the question that they have is how long do you leave the funnel of soil in the jar and under the light? They are trying to decide if they have time to run several samples through on funnel or if they need to do multiple.
Thanks

Hi Rkampmann1,

Welcome to the Ask an Expert forums! I looked at the procedure for the project and, like you, noticed that the project doesn't say how long to let the funnel sit. The important thing is to use the same amount of time for all of the trials.

Without doing the project myself, I'm not sure how long it will take for the micro-arthropods to fall down into the alcohol. You could leave the soil until the light for a few hours and then look at the alcohol to see if anything has come through yet. If micro-arthropods have fallen into the alcohol, then you could do more replicates using the same amount of time. If you don't see micro-arthropods in the alcohol, then you need to let the soil sit under the lamp longer. Given the uncertainty in how long it will take, I suggest running multiple samples at the same time using multiple funnels if you don't have a lot of time before the project is due.