TABLE 3.

Key phenomena for each THSB chapter

Chapter number and science ideas	Students observe, model, and explain these phenomena
1. New substances form during chemical reactions because atoms rearrange to form new molecules.	Why substances with different properties form when:
	• Vinegar is mixed with baking soda
	• Iron is exposed to oxygen in the air
	• Hexamethylenediamine is mixed with adipic acid
2. Mass is conserved in chemical reactions because atoms are conserved.	Why the measured mass of a system can change even though atoms are not created or destroyed when:
	• Vinegar is mixed with baking soda
	• Iron is exposed to oxygen in the air
	• Hexamethylenediamine is mixed with adipic acid
3. Animals build body structures for growth through chemical reactions, during which atoms rearrange and are conserved.	How animals produce proteins for growth of their body structures that are different from what they eat when:
	• Egg-eating snake eats only eggs but can replace its shed skin
	• Humans eat muscles but can also make tendons
	• Herring fish eat 14C-labeled brine shrimp and make 14C-labeled body structures (mostly muscle)
4. Plants build body structures for growth through chemical reactions, during which atoms rearrange and are conserved.	How plants produce carbohydrates for growth of their body structures that are different from substances they take in from their environment when:
	• Algae produce 14C-glucose from 14C-carbon dioxide and they produce 18O-oxygen (not 18O-glucose) from 18O-water
	• Mouse-ear cress plants make more 14C-cellulose from 14C-glucose when grown without herbicide than with it