Constructed Response
Laboratory Practices
Laboratory Practices
Teacher Guide
Students will need about 20 minutes to complete these constructed response tasks.
Objectives assessed:
• Demonstrate proper use of basic laboratory equipment.
• Demonstrate safe practices during laboratory and field investigations.
• Identify all safety equipment in the laboratory and explain or demonstrate how it is
properly used.
• Demonstrate knowledge of basic laboratory safety procedures.
• Locate material safety data information (typically MSDS) and identify important
information pertinent to health and safety for the use of a chemical.
• Explain or describe procedures to follow in emergency situations such as fire, bodily
injury, chemical spills, etc.
1. A laboratory procedure instructs you to mix 15 milliliters (mL) of 1M HCl with 100 mL of
distilled water. Describe in detail the steps you should take to complete this procedure
safely. In your response, be sure to:
• Explain how to use the MSDS for HCl.
• Describe all the laboratory equipment you will need and how to use it.
• List all personal safety equipment you should wear.
• Should you pour the acid into the water or the water into the acid? Explain why.
Correct response(s):
Sample Correct Response: First, consult the material safety data sheet (MSDS) sheet for
1M HCl; it should be stored with the other MSDSs in the science classroom. The MSDS will
tell you what safety procedures need to be followed when using 1M HCl. Because 1M HCl is
corrosive to skin and eyes, you should wear safety goggles, gloves, and a lab coat during
this procedure. You should measure 100 mL of distilled water using a graduated cylinder,
then add the water to a 150- or 200-mL beaker. Then measure 15 mL of HCl in the
graduated cylinder and add that to the water. Always pour acid into water; never add the
water to the acid, because the acid might splash.
Response scoring tool:
Score
Content
5
Meets all 5 of the following criteria:
• Thoroughly explains how to safely mix acid and water.
• Correctly explains the purpose of consulting the MSDS for HCl.
• Correctly identifies the graduated cylinder for measuring liquids.
• Correctly identifies the proper safety equipment for this
procedure.
• Correctly explains the safety rule of adding acid to water.
4
Meets 4 of the criteria listed above.
3
Meets 3 of the criteria listed above.
2
Meets 2 of the criteria listed above.
1
Meets 1 of the criteria listed above.
Discovery Education Science
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Laboratory Practices
0
No response, or response not appropriate to the question.
Discovery Education Science
© Discovery Communications, LLC
Laboratory Practices
Objectives assessed:
• Demonstrate proper use of basic laboratory equipment.
• Demonstrate safe practices during laboratory and field investigations.
• Identify all safety equipment in the laboratory and explain or demonstrate how it is
properly used.
• Demonstrate knowledge of basic laboratory safety procedures.
• Explain or describe procedures to follow in emergency situations such as fire, bodily
injury, chemical spills, etc.
2. During a lab, a beaker containing an acidic solution shatters in your hand. Explain how
you should safely respond to this event. In your response, be sure to:
• Clarify the order in which you should perform each action.
• Identify each piece of safety equipment you should use, and explain how to use it.
Correct response(s):
Sample Correct Response: First, I would alert the teacher. Then, I would walk to the sink,
turn on the faucet with my uninjured hand, and run the hand that was holding the beaker
under the water. When I have thoroughly washed off my hand, I should check to see if any
glass from the beaker has penetrated my hand. If so, I should allow my teacher or another
responsible adult to pull out the glass using tweezers. When I am sure there is no glass in
the cut, I should wash my hands again—this time with soap to reduce the risk of infection.
Then, I should apply pressure with a gauze pad to stop the bleeding and wrap the wound
tightly with an adhesive bandage. I can find all of these materials (tweezers, gauze pad, and
bandage) in the first aid kit in the science lab.
Response scoring tool:
Score
Content
5
Meets all 5 of the following criteria:
• Lists alerting the teacher as the first step.
• Second, explains how to clean the injured hand using water.
• Third, explains how to check for and remove glass from the
injured hand.
• Fourth, explains how to use a gauze pad from the first aid kit to
stop the bleeding.
• Fifth, explains how to wrap the wound with an adhesive bandage
from the first aid kit.
4
Meets 4 of the criteria listed above.
3
Meets 3 of the criteria listed above.
2
Meets 2 of the criteria listed above.
1
Meets 1 of the criteria listed above.
0
No response, or response not appropriate to the question.
Discovery Education Science
© Discovery Communications, LLC