Student Portal:

Kinetic and Potential Energy

Investigation 3 – Lab

 

 

 

 

 

 

 


MINDSET

This Investigation is designed to:

  • illustrate the conversion of energy from one form to another,
  • introduce you to chemical energy,
  • reinforce your understanding of the Law of Conservation of Energy as it relates to the conversion of energy, and provide practice in drawing best fit lines and using them to extrapolate data.

BE PREPARED

Student Preparation for the Investigation includes having students gather the following materials. This preparation takes place on lab day after student lab groups have settled at their assigned lab tables.

Note: The materials are listed in your SDR. They are also listed below for your reference.

  • (1) triple beam balance
  • (1) weigh dish
  • (1) lab scoop
  • (1) test tube rack
  • (4) 15 ml centrifuge tubes
  • baking soda
  • vinegar
  • (1) plastic dropper
  • (4) balloons
  • (1) clear metric ruler
  • (1) 35 cm piece of string
  • (1) marker
  • masking tape
  • (1) calculator

Direct one student from each lab group to collect the materials listed in their SDRs.

INVESTIGATE

  • A chemical reaction occurs when one or more substances undergo a change to form one or more new substances.
    • The new substances are different from the original substances.
    • Three signs of chemical reactions (there are many more) include the formation of gas bubbles, a change in color, and the production of heat.
    • Reflect on the PreLab video as you move through the procedural steps.
    • During the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help you keep on track, read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it).
    • Complete all of the procedural steps in your SDR.
  • Note: The procedural steps are listed below for your reference. 

    1. Use masking tape to label 4 falcon tubes.
      1. Label one tube “0 ml vinegar.”
      2. Label one tube “3ml vinegar.”
      3. Label one tube “6 ml vinegar.”
      4. Label one tube “9 ml vinegar.”
    2. Use a marker to label 4 balloons.
      1. Label one balloon “0.”
      2. Label one balloon “3.”
      3. Label one balloon “6.”
      4. Label one balloon “9.”
    3. Place the falcon tubes in the test tube rack. Remove the caps. 
    4. Use a plastic dropper to fill the tubes with vinegar. Do not add any vinegar to the tube labeled “0 ml vinegar.”
      1. Fill the tube labeled “3 ml vinegar” to the 3 ml mark with vinegar.
      2. Fill the tube labeled “6 ml vinegar” to the 6 ml mark with vinegar.
      3. Fill the tube labeled “9 ml vinegar” to the 9 ml mark with vinegar.
    5. Calculate: Measure the circumference of balloon 0.
      1. Measure the length of the black line on the balloon.
      2. Multiply the length by 2 to get the circumference. Circumference = 5 cm × 2 = 10 cm
    6. Record: Write the measurement in Table A under “Balloon Circumference Before Reaction” for 0 ml vinegar.

    Note: Table A is on the last page of your SDR.

    Trial 1

    1. In this Trial, you will create the control condition (0 ml vinegar).
      1. Stretch the balloon.
      2. Place a weigh dish on the triple beam balance and measure 0.5 g of baking soda according to the Procedure, Triple Beam Balance Use and Operation.
      3. Gently pour the baking soda into the balloon. Shake the balloon so that the baking soda goes all of the way into the balloon.

    Note: Make sure you stretch each balloon before adding the baking soda. This will allow the balloons to inflate more easily in the course of the experiment. Alternatively, you can blow the balloons up slightly and then deflate them.

    Note: If you have not had experience using a weigh dish to measure substances on the triple beam balance refer to the procedure Triple Beam Balance Use and Operation in your Procedural Toolbox.

    KE:PE 3 Lab Baking Soda Pouring

      1. Carefully stretch the neck of the balloon over the top of the centrifuge tube labeled “0 ml vinegar” so that the balloon hangs to one side. The baking soda should not fall into the tube. The neck of the balloon should be over all of the threads on the top of the falcon tube.

    KE:PE 3 Lab Balloon on Tube

      1. Lift the balloon so that all of the baking soda falls into the tube. You may need to shake the balloon slightly or tap the tube.
      2. Let go of the balloon.

    KE:PE 3 Lab Balloon Tip

    1. Record: What is happening in the tube? What is happening to the balloon? Write your observations in Table A on the last page of the Investigation 3 Student Data Record.
    2. Measure the circumference of the balloon using the following steps:
  • Do not remove the balloon from the tube.
  • Place one end of the string on the balloon.
  • Wrap the string around the balloon at the black line.
  • Hold on to the string where it meets the end.
  • Measure the string from the end to the point you are holding it with the ruler.
    1. KE:PE 3 Lab Ruler

      1. Record: Write the measurement in Table A under “Balloon Circumference After Reaction.”

      Trial 2

      1. Repeat steps 1a through 1f of Trial 1 for the tube labeled “3ml vinegar.”
        1. Record your observations in Table A.
        2. Measure the circumference of the balloon. Record the data in Table A.

      Trial 3

      1. Repeat steps 1a through 1f of Trial 1 for the tube labeled “6ml vinegar.”
        1. Record your observations in Table A.
        2. Measure the circumference of the balloon. Record the data in Table A.

      Trial 4

      1. Repeat steps 1a through 1f of Trial 1 for the tube labeled “9ml vinegar.”
        1. Record your observations in Table A.
        2. Measure the circumference of the balloon. Record the data in Table A.

       

    CLEAN UP

    Make sure you clean up your bench after your experiments.