Imagine you're a researcher studying how sleep affects mood. To explore the connection, you would look at two key "variables": sleep (how much someone gets) and mood (how happy or irritable they feel) ...

Scientists often want to find out if changing one variable makes a difference to other variables. In many (though not all) investigations the variables are kept constant - the control variables, apart ...

What Is the Scientific Method? The scientific method is a systematic way of conducting experiments or studies so that you can explore the things you observe in the world and answer questions about ...

The organic food industry has grown from fresh produce and grains to snack foods and condiments--from farmers markets to supercenters. Has this new variety in organic products, and the availability of ...

This paper describes an investigation of emissions from an engine featuring variable valve timing, a swirlcontrol valve and exhaust gas recirculation. Design of experiments has been used to model the ...