Throughout our unit on Matter, our 4th and 5th grade students have been provided with different opportunities to practice aspects of and demonstrate their understanding of performance expectations aligned with the Next Generation Science Standards (NGSS), for example: 5-PS1-4 Conduct an investigation to whether the mixing of two or more substances results in new substances. One of the lesson objectives was to identify different changes that can happen to matter. Students first learned how a chemical change is different from a physical change.
To wrap up the lesson, we conducted an experiment with a baking soda mixture and blackberries. Students first mixed baking soda with water and then used a cotton swab to write a secret message on a piece of paper. Once the water evaporated, baking soda crystals were left behind. We carefully rubbed a blackberry back and forth across the paper, and the secret messages were revealed! The purple pigment from the blackberries reacted with the baking soda crystals to form a new substance—which is a chemical change!