Course title
SCI031Pre-requisite
Successful completion of Biology and current science teacher approval required.Course description
Environmental Science is a lab-centered science course which integrates knowledge from Biology; Earth Science; Chemistry; Math; History; Philosophy; Sociology; and Law. This synthesis of information allows students to understand the interrelationships of the natural world; to identify and analyze environmental problems; to evaluate the relative risks associated with these problems and to examine alternative solutions for resolving and/or preventing them.
SAMPLES OF LAB WORK:
Inquiry Lab • Scientific Method
Chapter 9 Testing for Lead
Directions: Read the entire lab before doing the procedure and answering the questions.
Problem What common household and everyday items contain lead?
Background
Dangers of Lead Exposure
Ingesting or inhaling particles of heavy metals such as lead can cause neurological damage and grave illness; even at relatively low doses. Exposure to lead continues to be a serious health threat; especially to children.
Where Lead May Be Found
A major source of lead in homes is old paint; which some children ingest when they find paint chips on the floor. Lead is also found in many common household and consumer products; including old toys; some glassware; ceramic products; candlewicks; and even vinyl lunchboxes. Tap water that flows through lead pipes or nonlead pipes joined with lead plumbing solder are another potential source of ingestible lead. Solder is a metallic material used to fuse metal objects together.
Precautions and Protections
Although lead-free solder is more commonly used today to repair plumbing and household appliances; lead solder is still used for some repairs. Older houses may contain lead plumbing or solder; therefore; it’s important to run water for several seconds before drawing tap water for drinking or cooking. Also; the use of lead paint was not outlawed until 1978 in the United States.
Materials
• 6 lead test swabs • distilled water
• 3 250 mL beakers • lead fishing sinker
• warm tap water and cold tap water • 2 additional test objects
• painters’ masks (if handling dust) • 2 resealable plastic bags
Safety
Avoid contact with activated testing swabs. If you touch these accidentally; or if you touch an item that tests positive for lead; wash your hands thoroughly with soap and water. Follow your teacher’s instructions about proper disposal of test items and used swabs. Wash lab table or test surface thoroughly with soap and water. Wash your hands with soap and water when you are through.
Procedure
Step 1 Examine the items you will be testing (cold tap water; warm tap water; distilled water; fishing sinker; and two other items). Predict which items may contain lead. Record your predictions in the data table.
Step 2 Fill a beaker halfway with warm tap water.
Step 3 Put on gloves before you begin testing. Hold test swab with the tip pointing up. To activate the swab; squeeze and crush it at the points marked on the “barrel;” as demonstrated by your teacher. NOTE: You must use the swab immediately after crushing.
Step 4 With swab tip pointing down; shake swab twice; and then squeeze gently until yellow liquid appears at the tip.
SAFETY NOTE: Do not get liquid on your skin. If contact with liquid occurs; immediately wash with soap and water.
Step 5 While squeezing the swab; dip the tip in your water sample for 30 seconds.
If the swab tip turns pink or red; lead is present in your sample. If there is no color change (swab remains yellow); then no lead is present.
Record your result in the data table. Discard the used test swab in a resealable plastic bag.
Step 6 Fill your second beaker half full with distilled water. Repeat Steps 3–5. Fill your third beaker half full of cold tap water. Repeat Steps 3–5 again.
Step 7 To test for lead on your fishing sinker: first; activate the test swab as before (Steps 3–4). Then; while squeezing the swab; gently rub the swab back and forth across the fishing sinker for 30 seconds. Note your results in the data table. Discard the used test swab in a plastic bag. Place your sinker in a plastic bag but do not throw it in the trash can; instead; give it to your teacher.
Step 8 Repeat Step 7 for each of the two remaining test items. If you will be testing painted surfaces; objects; or any item that exhibits dust; wear a painter’s mask and gloves during testing. Avoid getting dust on your clothes.
Step 9 Follow your teacher’s additional directions for disposing of used test swabs and test items. Clean your lab table or working surface; and wash your hands thoroughly with soap and water.
Step 10 After you have filled in your data table; record your results; with the results of your classmates; on the classroom data table.
Observe and Collect Data
Complete Question 1 before you begin collecting data.
1. Write the names of the two additional items you will be testing on the data table; then predict which items will contain lead.
2. After testing each item; record your results on the data table.
DATA TABLE
Item Lead Present
(Predicted) Lead Present
(Observed) Lead
Not Present
(Observed)
Warm tap water
Distilled water
Cold tap water
Fishing sinker
1.
2.
3. Add your results to the class data table on the board.
Analyze and Conclude
4. Analyze Data Look at your group’s results and the class results. Which items tested positive for the presence of lead?
5. Explain Select two items that you tested; and explain why you predicted the presence (or absence) of lead for each. If your predictions were incorrect; why do you think this was so?
6. Compare Examine the class results; and compare items that tested positive for lead. Do any of these items have similar characteristics or qualities? If so; describe these similarities.
7. Infer Using the comparisons you made in your response to Question 6; are there any characteristics you could use to predict if an item contains lead?
8. Extension Based on your test results and observations; do you think there might be lead in your home? If so; name one or two areas or items that you think might contain lead. Then select one area or item; form a hypothesis about it; and prepare an action plan that your family can take to test your hypothesis.
Inquiry Lab • Scientific Method
Chapter 12 Testing Soil Properties
Directions: Read the entire lab before doing the procedure and answering the questions.
Problem What is the permeability of different soil samples?
Background
Permeability describes the ease with which fluids; such as water; can move through soil. The faster water can flow through the spaces between particles of soil; or pores; the higher the permeability of the soil. The slower water moves through soil; the lower its permeability. The size of the pores affects the permeability of soil. The smaller pore size of fine-particle soils; such as clay; makes it more difficult for water to drain through the soil. Soils with larger pore size; such as sand; have a higher permeability.
Materials
• soil samples: clay; loam; sand; and silt (200 mL plus one spoonful each) • microscope
• paper plate • marker
• spoon • 4 pieces of cheesecloth
• hand lens or magnifying glass • 4 rubber bands
• dropper • 100 mL graduated cylinder
• water • 4 large plastic cups
• 4 large paper cups • 4 large funnels
• pencil • stopwatch
Safety
Put on goggles and a lab apron before you start the lab. Wash your hands thoroughly with soap and warm water before leaving the lab.
Procedure
Step 1 Obtain the soil samples. Scoop one spoonful of the clay onto the paper plate.
Step 2 Rub a small amount of each sample between the pads of your index finger and thumb to help determine whether the soil sample is gritty; slightly gritty; or relatively smooth. Record; in your data table; observations about how the particles feel and how easily they separate.
Step 3 Use the hand lens to observe the particles. Record your observations about the size of the particles.
Step 4 Use the dropper to wet the spoonful of soil. Rub it between your fingers again. Record observations about how the particles feel when damp.
Step 5 Repeat Steps 2 through 4 with the remaining three soil samples.
Step 6 Based on your observations; make a prediction about the permeability of each soil sample. Through which sample do you think water will move the fastest? Through which will it move the slowest?
Step 7 Use the pencil to poke ten holes in the bottom of each paper cup. Be sure to make all the holes the same size.
Step 8 Use the marker to label each paper cup Clay; Loam; Sand; or Silt.
Step 9 Wrap a piece of cheesecloth tightly around the bottom of each paper cup. Secure it by folding the ends of the cheesecloth around the sides of the cup and wrapping a rubber band around the cloth.
Step 10 Place 200 mL of each soil sample into its labeled cup.
Step 11 Measure 20 mL of water into the graduated cylinder. Pour the water into one of the plastic cups. Mark a line on the cup at the water level. Repeat this step with the remaining three plastic cups.
Step 12 Place a funnel in each plastic cup. Then place the cups that contain the soil samples in the funnels—one in each funnel.
Step 13 Measure 100 mL of water into the graduated cylinder. Pour the water onto the clay sample. Use the stopwatch to time how long it takes for 20 mL of water to collect in the plastic cup. Begin timing as soon as you begin pouring the water. Record the start time and end time in your data table. (Note: If after 3 minutes; you have not collected 20 mL; just record the actual amount and move on.)
Step 14 Repeat Step 13 with each remaining soil sample.
Step 15 Follow your teacher's instructions for cleanup and disposal of materials. Wash your hands thoroughly.
Observe and Collect Data
1. Record your observations about each soil sample in the table below.
Data Table 1
Soil Sample Feel When Dry Feel When Wet Particle Size
Clay
Loam
Sand
Silt
2. Write a prediction about the permeability of each soil sample. Rank the order of the samples from highest permeability to lowest permeability; based on your observations.
3. Fill in the first two columns of the table with the data you collect. Then; for the third column; calculate each Elapsed Time by subtracting Start Time from End Time. (Fill in the last column as you answer Question 4.)
Data Table 2
Soil Sample Start Time End Time Elapsed Time
(min or sec) Percolation Rate (mL/sec)
Clay
Loam
Sand
Silt
4. Use your data to calculate the percolation rate; in mL/sec. (milliliters of water per second); for each soil sample. Write each soil’s percolation rate; in the appropriate box in Data Table 2.
Example Calculation: Suppose it took 5 minutes for 20 mL of water to pass through 200 mL of soil. First convert the time in minutes to seconds by multiplying by 60. Then divide 200 mL by the total number of seconds.
Analyze and Conclude
5. Analyze Was your prediction about the permeability of the soil samples correct? Why or why not? Based on your results; rank the permeability of the soil samples tested from highest to lowest (from left to right).
6. Apply Take a loam sample from your teacher. Assume that the loam soil sample you used consisted of 20 percent clay; 40 percent sand; and 40 percent silt. Now suppose you have a soil sample that consists of 35 percent clay; 10 percent sand; and 55 percent silt. Predict the permeability of this sample relative to your sample of loam. Explain your reasoning.
7. Explain What is the relationship between pore size and permeability of a soil?
8. Evaluate What was the independent variable in this experiment? What was the dependent variable? Which variables remained constant in this experiment?
9. Extension Make an inference about which type of soil would be best suited to growing a vegetable garden. Explain why your choice helps the plants’ roots get what they need in order to grow.
School country
United StatesSchool state
ArizonaSchool city
TucsonSchool / district Address
2475 W Naranja DriveSchool zip code
85742Date submitted
Approved
YesApproved competency code
- LINT
- Integrated science