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5th Grade Science Lesson - Digestive System



Nathan Yerkes (with Natalie)

Digestive System Mini-Unit                                                                                    11/08/04


Day One



To introduce the functions of the digestive tract. (For day one; specifically, the teeth, saliva, the tongue, and esophagus.)



Students should know why they eat food, how it helps for their survival, and how food is broken down and distributed throughout the body by the digestive system. They will learn about the digestive system through hands-on experience and by answering questions about the different functions of the digestive system.


Prior Knowledge:

Students may already know the names of some of the parts of the digestive system. They know what teeth are used for. They know they have saliva. They know not to choke on food, among other things.


Objectives and Assessment:

Students will be able to explain that different teeth perform different functions. They will be able to explain that the front teeth are used for cutting and the rear teeth are for grinding. They will fill in the blanks on a handout labeling canines, premolars, molars, and incisors.

They will be able to explain that saliva is used to help get foods down the esophagus and that saliva turns starches into simple sugars. After shown an experiment with iodine and crackers students will be able to explain that there is a chemical reaction taking place when saliva is in contact with a cracker, or starch.

On day three of the mini-unit students will make their own model of the digestive tract showing their understanding of the lessons.



Study showing that the color of the iodine changes when iodine is placed on a cracker that has not been chewed yet as compared to a cracker that has.



Questioning in the beginning of the lesson to find out their prior knowledge of the subject. Activity using iodine and crackers. Activity of biting into an apple and students counting the number of teeth and recording the radius of their teeth. They will chew crackers using only their front teeth and then we will discuss what the function is of the front teeth and the back teeth. I will show them on a model of a humanís skeletal face what the different teeth are called. Then they will complete a handout labeling the different teeth. They will chew a cracker for a decent amount of time until they recognize that it becomes sweet and sugary.



Apples, human face skeleton model, iodine and crackers, and a tooth labeling handout


Questions and Examples:

What do you already know about the digestive system? If I gave you a sandwich what would you need to do to get nutrients from it into your body? Could you swallow it whole? What if it was dry? Why do you think when iodine is placed on a dry cracker and then on a cracker with saliva the outcome is different? What was it like chewing a cracker with only your front teeth? How are the functions different between your front teeth and your back teeth? If you chew a cracker for a long time without swallowing it how does the taste start to change? What do you think is happening? How many teeth did you count after biting into an apple? What was your teeth radius?



A recap of the main points discussed during the lesson. I will assess their understanding by seeing if they can explain to me when I ask them of the functions of the teeth, the tongue, saliva, and the esophagus. Then I will let them know that in a couple of days they will be expected to make a working model of the digestive tract.