It was very hot outside. It was so hot that Jilly's skin felt like it was on fire. "This is December," she thought. It shouldn't be this hot outside.' She remembered her dad saying, "When I was a boy, the month
of December was so cold that I had to bundle up to go outside." Willy had on shorts and a tank top. Looking
at a flowering rose bush, Jilly remembered her grandma saying that it was unheard of for a rose bush to
have flowers in December when she was a girl. Earlier this year, in science class, Jilly studied greenhouse
gases and learned that the greenhouse gases were responsible for trapping heat from the sun on Earth.
Since the industrial revolution, humans have move greenhouse gases from where it is safely stored in the
ocean and in the earth to the atmosphere. In the atmosphere the greenhouse gases are causing Earth's
surface temperature and atmospheric temperatures to go up.
Jilly wondered, "Will pure carbon dioxide, a greenhouse gas, cause the temperature to rise higher than the
natural air that surrounds us will?" Jilly decides, 'Pure carbon dioxide a greenhouse gas, will cause the
temperature to rise higher than the natural air that surrounds us will
What are the controlled variables? (Factors that are the same in both
groups) *