Hot Air, Cold Air
Students conduct experiments to see that air expands when heated and contracts when cooled. They also observe that hot air rises in cooler air. By modeling the expansion and contraction of air particles, they see that warm air is less dense than cold air. They also learn the role of heat energy in the expansion and contraction of gases.
Learn by Reading
For additional content-area reading, check out the Houghton Mifflin Science eBook: Grade 1, Unit F, pages 8–11.