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Common Core Standards: ELA - Literacy

Grade 11-12

Reading RST.11-12.3

RST.11-12.3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.

Set the Stage

Precision is important in the laboratory: for safety, for accuracy, for recording, and for drawing conclusions. In this standard, students must be able to follow proper safety precautions, complete a step-by-step process in the correct order, and take and record measurements. In 11th and 12th grades, students also must be able to analyze the results of their experiences in light of the explanations given in the text. In other words, students should not only read and follow directions, but also be able to apply their reading to an analysis and interpretation of the results they see in the experiment.

Example

Dress Rehearsal

In chemistry class, you are often asked to prove the concepts that you have learned within the chapter. Let’s say that you have been studying states of matter, including liquids and gases. Your teacher has asked you to demonstrate your understanding of these two states by conducting an experiment in which you follow a step-by-step process, take measurements, and draw conclusions from the result.

You will be comparing rates of evaporation. You learned in the chapter that two elements determine this: the volume of the liquid and the amount of available energy. Your research question: How do intermolecular forces affect the evaporation rates of liquids? You’re curious to know that. When you forget to turn on the bathroom ventilation fan, the mirror fogs up and it takes forever to clear. We won’t mention that the textured ceiling is beginning to peel.

Your teacher has set up your lab station with all the appropriate materials, and you put on your safety equipment. Protective glasses. Check. Protective gloves. Check. You note the dangers that could arise during the experiments as well, such as toxic and flammable chemicals, extreme temperatures, and fumes. You’re ready, steady.

Be sure to conduct these step-by-step procedures in the order given. You label five small plastic cups with the letter of each of the following liquids: distilled water (a), ethanol, (b) isopropyl alcohol (c), acetone (d), and household ammonia (e). You put all of these on a paper towel. With an eye dropper, carefully measure 1 ml. of each liquid and put into the cup. Ahem… we said CAREFULLY! Place each eye dropper on the paper towel directly in front of each respective cup.

Next, place a drop of the first liquid on a piece of wax paper. With your stopwatch, time how long it takes for that drop to evaporate. Record your time. Repeat the wax paper and timing procedure until you have tested all five liquids. Be sure to record the evaporation times as you move through the experiment. Your teacher has provided you with a warm sample of ethanol so that you can compare how heat affects the evaporation rate.

Afterwards, clean up your area, remove your protective gear, and wash your hands. You’re ready to analyze your data. Which liquids evaporated the fastest? The slowest? In which liquids are the attractive forces between the molecules dispersion forces? Would pure alcohol and pure ammonia evaporate more quickly or more slowly than the mixtures used in the experiment? What effect does heat have on the two ethanol samples?

In this experiment, your results should align to the concepts learned in the chapter: Water has a high surface tension, making it slower to evaporate. Chemicals mixed with water will evaporate more slowly than pure chemicals alone. As temperature rises, molecules disperse, thus speeding up the evaporation process.

Now for a real-world application: Your bathroom mirror is slow to evaporate because water molecules hang on to each other for dear life. When you turn on the fan, it evaporates more quickly as molecules are pulled apart by the air movement. Make sense?

Source:
Buthelezi, Thandi, et al. Chemistry: Matter and Change. New York: McGraw Hill, 2008.

Quiz Questions

Here's an example of a quiz that could be used to test this standard.

True/False

  1. Conducting an experiment on a new concept usually requires you to recall what you’ve learned in the past.

    Correct Answer:

    True

    Answer Explanation:

    The correct answer is (T). It’s always important to be able to situate new information in the context of information you’ve already learned.


  2. Steps in a procedure can be completed in any order as long as all of them are completed.

    Correct Answer:

    False

    Answer Explanation:

    The correct answer is (F). In an experiment, the order of the procedure is extremely important. Completing the steps out of order will yield completely different results and may even be dangerous.


  3. You should record data as the experiment progresses rather than waiting until the end.

    Correct Answer:

    True

    Answer Explanation:

    The correct answer is (T). We know you have the best memory on the planet, but humor us and record your data as you go, just in case. Just one mistake in your measurements can throw the experiment completely off track.


  4. The only safety precaution needed in an experiment is to put on safety goggles.

    Correct Answer:

    False

    Answer Explanation:

    The correct answer is (F). Goggles are good, but so are gloves, an apron, and closed-toed shoes. It’s also a good idea to tie back your hair or any loose-fitting clothing that might get in the way, and sometimes even more specialized safety equipment will be needed. Always read the lab procedure thoroughly before you begin to ensure you’re following all necessary precautions.


  5. The last step of an experiment is to put your equipment back.

    Correct Answer:

    False

    Answer Explanation:

    The correct answer is (F). What about the results? The last step of an experiment is to analyze and interpret the results. Usually you’ll conclude your lab report with a discussion of the results and their implications.


  6. Measurements must be taken precisely.

    Correct Answer:

    True

    Answer Explanation:

    The correct answer is (T). In science, things often come down to milliliters and millimeters. These tiny differences in measurement can have a big impact on the outcome of the experiment. That’s because an experiment is often a miniature version of something that’s happening on a much larger scale in nature, so those microscopic differences in the lab sometimes represent major differences in the real world. Be precise!


  7. The purpose of an experiment is to prove or disapprove accepted facts.

    Correct Answer:

    True

    Answer Explanation:

    The correct answer is (T). There’s only two ways this can go, folks. The experiment can confirm what we already believe is true, or demonstrate that what we thought was true isn’t quite right. Experiments don’t always give us all the answers or tell the whole story, but by confirming or denying various facts, researchers can figure out what to test next and get us (ever so slowly) closer to a new understanding. It’s like a never-ending game of twenty questions.


  8. It is important to read the legend before conducting an experiment in order to note the possible dangers.

    Correct Answer:

    True

    Answer Explanation:

    The correct answer is (T). All lab procedures will warn you of possible dangers and explain the necessary precautions needed to keep you safe. Read it, yo!