Make slime and/or oobleck and/or flubber. Compare their properties.
Science content (2016 curriculum):
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Chemistry: Chemical Changes (2, 7)
Curriculum connection (2005 science topic):
Physical Science: Properties of Matter (grade 2)
Physical Science: Chemistry (grade 7)