Name:________________________________        Date:__________        Hr:________

Mechanical and Chemical Digestion

Purpose:

Mechanical digestion begins to occur in your mouth. It is when your teeth grind and break up your food before it travels down your esophagus and then into your stomach. Chemical digestion also begins to occur in your mouth when the enzymes in your saliva begin to break down your food, and continues in your stomach and intestines. The purpose of this lab is to demonstrate the importance of mechanical digestion.

Materials:

• Two 250 ml beakers
• 2 sugar cubes
• Hammer
• Paper
• Warm water
• Two plastic spoons

Procedure:

1. Place one sugar cube on top of the piece of paper.
2. As carefully as you can crush it up with a hammer. Be careful not to lose any sugar pieces on your table or the floor.
3. Take the piece of paper with the sugar on it and carefully slide the sugar into one of the 250ml beakers.
4. Place the other whole sugar cube into the second 250 ml beaker.
5. Pour 150 ml of warm water into each of the beakers. Try to do this simultaneously with both beakers with the help of your lab partner.
6. You and your lab partner should immediately begin to stir the water and sugar using the plastic spoons.
7. Observe what happens and answer the questions below.

Questions:

1. When you hammered the sugar cube into smaller pieces was that mechanical or chemical digestion? Explain.

2. When you dissolved the sugar into the warm water was that simulating mechanical or chemical digestion. Explain.

3. Which dissolved faster the whole sugar cube or the crushed sugar cube? Explain.

4. How does this lab relate to digestion in your stomach?

5. Why is it important we have mechanical digestion along with chemical digestion?