Science Buddies: "Ask an Expert"

doing a project on reducing the amount of garbage put out on the curb each week by recyling. Would the variable be the amount of family members? Also, what could be the control?

Hi,

Great idea for a science fair project! Since this is a science project, you need a quantitative experiment. With garbage, the best quantitative measurement is probably weight. I don't know what you were thinking about doing, but perhaps you could weigh garbage cans before recycling efforts are started and calculate kilograms garbage (use metric for science projects)/person in household for 2-3 weeks. Then, after a recycling awareness effort, you could measure the weight again. Your project would be improved if you had as many samples as possible.

It's interesting, but I could easily not find any scientific references on this topic. What do you have for your background reading information? With science projects, it usually best to have a project based on a scientific principle.

What were you planning to do for an experiment?

Donna Hardy

Dear yara289,

In terms of the variables, I suggest sticking with one household to begin with because using different families will change other factors that you can't control (number girls vs. boys may affect the amount of garbage, habits of the family members, etc). In order to show that your results can be replicated, try weighing the garbage for two or three weeks, as Donna suggested, and comparing the results for each week. You can use other families as well, but you must be careful only to compare the results of that family to other results of that same family (from another week).

Hope this helps!
Michelle

Thanks Michelle & Donna: The suggestion is from EPA, designing environmental projects. Not much reading background other than to sort total garbage weight into recyclable, reusable, biodegradable and trash. So it's the before amount vs. the amt. after recycling. Our project was based on one week's worth of trash for a family of four and it is amazing how you can cut down on the actual waste you have hauled away. yara289

Congratulations! It sounds like the experiment went well. Let us know if you have any other questions.

Michelle

OK, we are now in the process of putting the project on a board. Title is: What % of your weekly garbage is recyclable? Hypothesis: One-third of weekly garbage can be recycled. Can you think of a better hypothesis? must we state 33 1/3% instead of one-third?? Our charts are in weight in pounds, must we convert our charts to kilograms? Will the average person know that 21.7724 kilograms of recyclables is equal to 48 lbs.?? thanks.

Hi,

While the most scientific work is reported using metric units, my guess is that 80% pf the US population has no idea what the metric system of units is. You can check this out by asking 10 random people in your school how to convert pounds to kilograms. My guess is that unless they have taken high school science, they won’t know. My guess is also that almost no aduts will know.. I would use one third rather than 33 1/3%, particularly unless you know the answer is good to three significant figures. Your hypothesis sounds fine to me.

These are just my opinions amd others may disagree.

Sounds like a great project!

Best regards,

Barrett L. Tomlinson

Personally, I would use the metric system to display the numbers, since that is what scientists generally use. I would, however, put beneath the chart a conversion to give people a sense of what that is in pounds. But if you have encountered problems communicating the data to people because of this issue, leave the numbers in pounds.

Michelle

Thanks Barrett & Michelle, so grateful for your input & suggestions.
yara289

WON! what are the main points in writing an "essay" on science Project??