Make meringues, and while cooking, explore the science of meringues e.g. what make the foam.
Science content (2016 curriculum):
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Atoms, Molecules (3-7)
Chemistry: Physical Changes, Solutions, Mixtures and Separating (2, 4, 5, 6)
Science topic (2005 curriculum connection):
Physical Science: Chemistry (grade 7)