1. HW: Study for the Unit Test on Fri
HW: Study for the Unit Test on Fri. 1/13 10 or more Index Cards = + 2 pts Sherlock # on Friday
Do Now: /11/17
Today we will finish the “What Chemical Wastes are Excreted by the Body” Lab – pgs
Gather your lab materials and turn to the lab pages for instructions on completed the experiments. You will begin soon!
Urine
Sample

2. Chemical Waste Lab – pg 55 Blue (-) Pink (+) Part A
Testing for moisture
1. Examine dry cobalt chloride paper and record color.
2. Place a drop of water on the paper.
Record the color after the paper has been exposed to
moisture.
Cobalt Chloride Paper
Color
Dry
Wet (distilled H20)
Blue (-)
Pink (+)

3. Chemical Waste Experiments
Part B
Testing for salt
1. Fill a test tube ¼ with distilled water
2. Fill a second test tube ¼ with salty water
3. Add 1 drop of silver nitrate to each tube.
4. Record color of both tubes in data table.
Wear safety goggles!
Type of Water
Color
Distilled Water
Salty Water
Clear (-)
Cloudy (+) + -

4. Chemical Waste Experiments
Wear safety goggles!
Part C
Testing breath lungs for moisture and salt
1. Place a dry piece of cobalt chloride paper in a plastic baggy.
2. Hold the baggy to your mouth and breathe into it 5 times.
3. Hold the baggy closed for 2 minutes. Record the color.
4. Tear the baggy open and soak up any liquid inside.
Roll up the cotton and fit it into a test tube.
Fill the tube ¼ with distilled water. Add 1 drop of Silver
Nitrate. Record the results.
Cobalt Chloride Color
Water given off?
Silver Nitrate Color
Salt
given off?
Part C:
Breath from lungs
Pink (+)
yes
Clear (-) no

5. Chemical Waste Experiments
Wear safety goggles!
Part D
Testing skin perspiration for water and salt
Hold a piece of dry cobalt chloride paper in your hand with your fist closed for 5 minutes. Record the results.
Rub the palm of your hand with clean cotton, roll it up and place in test tube. Fill the tube ¼ with distilled water.
Add 1 drop of silver nitrate. Record the results.
Cobalt Chloride Color
Water given off?
Silver Nitrate Color
Salt
given off?
Part D:
Skin Perspiration
Pink (+)
yes
Cloudy (+)
yes

6. Chemical Waste Experiments
Wear safety goggles!
Part E
Testing urine for water and salt
Fill a test tube ¼ full of “urine”. Tip the tube and insert cobalt chloride paper to test for moisture. Record results.
Add 1 drop of silver nitrate to the contents of the test tube. Record the results for the presence of salt given off by the kidneys.
Cobalt Chloride Color
Water given off?
Silver Nitrate Color
Salt
given off?
Part E:
Urine from Kidneys
Pink (+)
yes
Cloudy (+)
yes

7. Kidneys Lungs Skin Yes Water Salt Conclusion Questions
Name three organs that give off waste chemicals:
_____________ _____________ ____________
Do the lungs help to get rid of wastes? ____________
a. What waste(s) was shown to be given off by the
lungs in this experiment?
________________
b. What waste(s) was shown not to be given off by the
Kidneys Lungs Skin
Yes
Water
Salt

8. Yes Water and Salt Yes Water and Salt Conclusion Questions
3. Does the skin help to get rid of wastes? ___________
What wastes were shown to be given off by the skin
in this experiment?
___________________________________________
4. Do the kidneys help to get rid of wastes? ___________
What wastes were shown to be given off by the kidneys
Yes
Water and Salt
Yes
Water and Salt

9. Yes Yes Organ Water Salt Carbon Dioxide Urea Lungs + - Skin Kidneys
5. A scientist drew up the following chart based on her results from a similar experiment. The chart appears as follows:
Organ
Water
Salt
Carbon Dioxide
Urea
Lungs + -
Skin
Kidneys
Do your results agree with the scientists for the test on water? __________
b. Do your results agree with the scientists for the test on
salt? ___________
Yes
Yes

10. Skin & Kidneys Lungs Lungs, Skin & Kidneys Skin & Kidneys Organ Water
6. Examine the chart again.
Organ
Water
Salt
Carbon Dioxide
Urea
Lungs + -
Skin
Kidneys
List the organs that give off urea
_____________________________________________
List the only organ that gives off CO2
List those organs that can give off water
List those organs that can give off salt
Skin & Kidneys
Lungs
Lungs, Skin & Kidneys
Skin & Kidneys

11. The Excretory System HW

12. Excretory system HW Answers
1. What three substances do the excretory system remove from the body?
Carbon dioxide, water, salt, heat and urea
2. Describe the pathway of urine from its formation to elimination.
Kidneys  ureters  bladder  urethra
3. What is the main organ of excretion? What are the other organs?
The kidney is the main organ of excretion. Other organs include the lungs, skin, bladder and liver.

13. Continued
4. How do the kidneys maintain water balance?
Kidneys will reabsorb water into the body if it detects the body is dehydrated. It will rid the body of excess water.
5. Where in the body are the nephrons? Name the 2 step process in which they help produce urine.
The nephrons are in the kidneys.
1: Wastes and needed materials are filtered out of
the blood and eliminated.
2: Needed materials are returned to the blood.
6. Kidney Ureter
8. Bladder urethra

14. Continued Collecting wastes and removing them from the body
10. What is excretion?
Collecting wastes and removing them from the body
11. Compare and contrast the ureters and urethra.
Similar: both are tubes that carry urine
Different: ureters are attached to the bladder and kidneys. Urethra is attached only to the bladder.
12. What is urea?
A chemical that comes from the breakdown of protein
13. What is urine?
A watery fluid that contains urea, salt and water

15. True
False
True
True
False
False
True
False
True
False
True
False

16. Skin
Lungs
Kidney
Urinary Bladder

17. Excretory System
Tim and Moby