From Seed to Seed:
Plant Science for K-8 Educators

Oils and fats. Like carbohydrates, oils and fats are made up of carbon, hydrogen, and oxygen atoms. However, the ratio of these three elements is different in oils/fats.

In both plants and animals, oils and fats provide important reservoirs of stored energy. Because they contain more than twice as many calories per gram as do carbohydrates or protein, oils and fats are concentrated energy supplies. While carbohydrates, and especially simple sugars, are immediate sources of energy, oils and fats take longer to metabolize and are used for long-term storage.

Most important oils come from seeds. Your grocery store probably stocks a number of cooking oils that are extracted from seeds. Again, you can ask your students to conduct a grocery store investigation. How many different kinds of oils can they find? What plants did they come from? Examples include corn, soybean, sunflower, safflower, sesame, peanut, and canola oils. (Canola oil is extracted from rapeseed, Brassica napus.)

Counting Calories. Oils and fats contain 9 calories per gram. Carbohydrates and proteins both contain 4 calories per gram.