Download Digestion in the Stomach - 5

Digestion in the Stomach ­ 5
Day 1
Volume Mass
Day 2
Volume Mass
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Digestion in the Stomach ­ 5
Inquiry 5.1
Problem: Which digestive chemicals in the stomach cause food to break down? Which chemical works the best?
Procedure; Place 4ml. of the four chemicals, hydrochloric acid, pepsin, gastric juice and water into each of four labeled test tubes. Measure the length, width and height and mass of 4 similar pieces of egg white. Tie with a string and immerse under liquid in labeled test tube. Heat an hour at about 37 degrees Celsius. Check in 24 hours and measure again.
1. What is the independent variable in this laboratory inquiry? Explain why.
2. What is the dependent variable? Why?
3. What tools and units will be used to measure the dependent variable?
4. What are the constants (controlled variables)? List at least four. 5. What will be the control for this activity? Explain why. 6. How do you calculate the volume of a solid rectangular object? 7. Which of the major food types (nutrients) is egg white?
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Digestion in the Stomach ­ 5
Inquiry 5.1
Problem: Which stomach digestive chemicals cause chemical digestion to break food down? Do all the chemicals cause the same change. Procedure; Place 4 ml. of four chemicals, water, pepsin, gastric juice and HCL into four labeled test tubes. Measure the length, width and height and mass of 4 similar pieces of egg white. Tie with a string and immerse under liquid in labeled test tube. Heat an hour at about 37 degrees Celsius. Check in 24 hours and measure again.
1. What is the independent variable in this laboratory inquiry? Explain why. Changing chemicals ­ HCl, pepsin, and gastric juice (and water)
The chemicals in the test tubes are being changed by the experimenter. 2. What is the dependent variable? Why? The mass (g) and volume (cm3) of the egg white
The data collected is the mass and volume of the egg white. (what changed because of the independent variable)
3. What tools and units will be used to measure the dependent variable? Mass in grams will be measured using a scale and a ruler will be used to measure length, width and height in cm which will be multiplied to get cubic centimeters.
4. What are the constants (controlled variables)? List at least four. The amounts of chemicals, the size of the egg white, the heating to 37* Celsius, the time in the chemical will all be kept the same.
5. What will be the control for this activity? Explain why. Egg White in water
The egg white in water will be compared to the egg white in the other chemicals. 6. How do you calculate the volume of a solid rectangular object? Multiply the length times the width times the height to get the volume of the rectangular prism in cm3.
7. Which of the major food types (nutrients) is egg white?
Egg white is protein.
8. Why are the tubes heated to 37 degrees Celsius?
37 degrees Celsius is equal to 98.6 degrees Fahrenheit ­ about our body temperature. 3
Digestion in the Stomach ­ 5
Questions on the Reading:
1. What chemicals are found in the stomach?
Pepsin and hydrochloric acid make gastric juice.
2. How many layers of muscle are in the stomach? Three layers of muscles at various angles are found in the stomach.
3. What is the liquefied food leaving the stomach called?
Chyme
4. What substance protects the stomach lining?
Mucus
5. What is a small hole in the stomach lining called?
Ulcer
6. Many adults experience pain caused by stomach acid backing up into the esophagus called Heartburn
7. Spoiled food , some medications, poisons and illness can cause the stomach to contract violently. This action is called Vomiting
8. What enzyme is found in the stomach? Pepsin
9. What nutrient undergoes chemical digestion in the stomach? Protein
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Digestion in the Stomach ­ 5
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