Science Buddies: "Ask an Expert"

I'm testing wind speed using an anemometer. My test will be done in the woods, in a meadow, and on a hilltop. It will be done in the morning, afternoon and evening. What are my constants and variables.
I know my watch(minute of time) is a constant but is the wind a constant or variable? what about the location and time of day?

Hi Bud,
I assume that you are testing how those different locations and times of day affect wind speed? If so, your variables include the windspeed (dependent variable) location (independent variable) and time of day (independent variable).
If you haven't already read our information on variables, that should be helpful:
http://www.sciencebuddies.com/science-f ... bles.shtml
I assume that "constants" are the same as "controlled variables" discussed in the link above. Any factor that could possibly affect the wind speed and is not included in your independent variables is a variable that should be constant or "controlled". In studies of natural systems, there are some things we can control, but other things we just hope will remain constant.

So, first of all, think about things that you can control in your experiment and which aren't an independent variable. One example is your general location. What if you took a meadow measurement outside your home and a hilltop measurement at the North Pole? In that case, the different latitudes would make it difficult to interpret your results (was it windy on the hill because it was a hill or because it was at the north pole?), so it becomes clear that latitude and longitude are variables that you will want to control (keep constant) as much as possible. In other words, you would ideally test a hilltop, meadow, and woods that are in very close proximity.

Next, think about some factors that you can't necessarily control yourself, but could still mess up your experiment. What if a small thunderstorm blew over the hill as you were taking your measurements there, but it was not stormy down in the meadow? The local weather seems to be another variable that you would want to control. Of course you can't control the weather, but you can choose to take measurements on a day when the weather is expected to be similar over a wide area. You should be able to think of other examples like these.

I hope that helps!
Chris

To simply put it, variables are the factors that you are able to manipulate in order to make some conclusion about their effect on the variable.
Since location is not something you are investigating or experimenting with, it should be a constant.

Hope this helps!
-Dan