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Tadpole to Frog

Chapter 8’s experiment for Biology Level 1 takes students through the life cycle of a frog, from tadpole to adult. Students use their powers of observation and classification to record the metamorphosis. The variation suggested for this experiment is to allow students to observe the development of a different kind of frog to record differences and similarities (which provides more practice in accurate scientific observation).

You may even wish to allow students to observe the growth of two differing frogs simultaneously so that they can observe differences and similarities directly instead of relying on their drawings and notes. This would require two small aquariums, however, so conducting two experiments in development at the same time is not necessary.

I. Prepare the lab notebook
Have students create a new Objective and a Hypothesis about whether the second type of frog will develop differently. They may wish to draw the changes they observe in addition to recording the physical changes they see each week.

Other online resources for purchasing tadpoles include online resources Home Science Tools and Carolina Biologicals.

II. Follow the same experiment steps as provided in the Lab Workbook.
If you have purchased the tadpoles, be sure the students accurately label the aquarium and their notes with the frog’s proper name. If you are using specimens from a local pond and do not know the species, write a descriptive “name” based on appearance and size.

III. What happens?
Were there any observable differences in the starting size of the tadpoles and in their coloring or transparency? Did the second species begin some changes sooner or later in the life cycle? Help students write valid conclusions based on their new observations.

Feel free to write to us with information about how the experiment variations and expansions are received by your students. We appreciate all feedback.


How Do They Eat?

The Biology Level 1 experiment for Chapter 7 allows students to use a light microscope to observe how paramecia and amoeba eat their food in differing ways. The red-stained baker’s yeast can be seen turning blue as it is digested, if observations are made over sufficient time.

Does the specific food provided change how each of these amazing single-cell creatures eat? Using most of the same lab materials gathered for Experiment 7 in the Lab Workbook, students can test a second food substance – brewer’s yeast – and observe if there is a difference in the feeding behavior.

I. Prepare the lab notebook
Have students create a new Objective and Hypothesis about whether one or both types of protozoa will feed exactly the same or whether any differences will be observed.

II. Recreate the experiment steps using brewer’s yeast instead of baker’s yeast
Substitute brewer’s yeast for the baker’s yeast. Have students observe the feeding and digestive process of both the amoeba and the paramecia with this new food.

III. What happens?
Were they any observable differences in how the protists eat? Help students write valid conclusions based on their new observations.

Feel free to write to us with information about how the experiment variations and expansions are received by your students. We appreciate all feedback.


Before I discuss what is not covered in Level II Chemistry, I wanted to let you know about the scope and sequence for all of the RS4K future products. A “B” series is now in development. The “B” series will compliment the current RS4K books from each level. Topics not covered in the “A” series, will be covered in the “B” series. I have put some tentative release dates for a few of the books, but these are, as always, subject to change. This should give you some idea of how the final RS4K series will look.

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Several of you have asked if Level II Chemistry can be used as a high school text and if Level II Chemistry meets the high school SAT requirements.

Level II was not intended as a high school text and I have not typically promoted the text as a high school textbook. However, after looking at the high school SAT subject requirements, I think it comes very close.  With the exception of a few topics, Level II Chemistry nearly meets the full requirements for high school SAT preparation and, from what I can see, I think it covers enough topics in enough detail to qualify as a high school chemistry credit. 

I have prepared a series of tables illustrating the high school SAT subject requirements for Chemistry and the topics that RS4K Level II Chemistry meets.

Anticipated Skills

The first table shows a list of the Anticipated Skills from the SAT Chemistry subject webpage.

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Structure of Matter

The next table shows a list of specific requirements for the topic “Structure of Matter.” As you can see there are a few specific topics, such as Lewis dot structures and dispersion forces not covered in Level II Chemistry. Also, oxidation-reduction is not covered in Level II Chemistry. That will be covered in Level II Chemistry “B” series.

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States of Matter

The next table shows a list of specific requirements for the topic “States of Matter.” As you can see there are a few topics related to gases that are not covered in Level II Chemistry. Those will be covered in Level II Chemistry B series.

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Reaction Types

The next table shows a list of specific requirements for the topic “Reaction Types.” The Bronstead-Lowry theory of bases is not covered in Level II Chemistry, instead the Arrhenius theory is introduced. 

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Stoichiometry

The next table shows a list of specific requirements for the topic “Stoichiometry.”

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Equilibrium and Reaction Rates

The next table shows a list of specific requirements for the topic “Equilibrium and Reaction Rates.” As you can see, there is no discussion of Equilibrium in Level II Chemistry. That will be covered in the “B” series.

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Carbon Chemistry

The next table shows a list for the topic “Carbon Chemistry.” Organic chemistry and biochemistry topics are not listed on the SAT website specifically. However, some introduction to both organic chemistry and biochemistry is helpful for college level chemistry, and because Level II Chemistry does cover these in some detail, I have included these topics in a table called “Carbon Chemistry.”

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Summary

You can see that RS4K Level II does not cover some of the recommended topics for high school SAT preparation, but it does cover other topics not discussed on the SAT webpage. So the decision to use the RS4K Level II book for high school or SAT preparation is really up to the individual parent and student. I wrote these books to cover some of the core foundational topics in greater detail than typical science text books. I believe that covering a few topics very well is more important than covering many topics not-so-well. One of the major complaints I hear from both professors and students about college freshman chemistry is that it covers far too much material in a semester for many students to really grasp. The same is often true of high school chemistry. So with that in mind, I wrote the RS4K series to cover fewer topics, but in greater detail and although RS4K Chemistry Level II does not cover every SAT recommended topic, I believe it gives students a much better understanding of the topics that are covered.

Let me know if you found this helpful or if there is other information you need.

Warm wishes,
Rebecca Keller


How Do They Move?

The Biology Level 1 experiment for Chapter 6 introduces students to the use of a microscope and to protists that can be viewed using the microscope. Learning to properly use a light microscope to view the movement of the three types of protozoa can be tricky, especially for younger students. But once they master the viewing alignment, they will likely want to use it further to learn more. 

Using the same lab materials gathered for Experiment 6 in the Lab Workbook, let’s take a close look at how temperature changes affect (or do not affect) the protists. What if the water on the slide is cold? What if it is warmer than room temperature?

I. Prepare the lab notebook
Have students create a new Objective and Hypothesis for each of the two temperature variations as they apply to ciliates, flagellates and amoeba. Create boxes or spaces in the lab notebook to note the results on the three types of protozoa.

II. Recreate the experiment steps with slide samples of varying temperature
To observe the effects of cold on the protozoa, put the tube in the refrigerator for about 15 minutes and then observe droplets under the microscope. To warm the protozoa, place the tube in lukewarm (not hot!) water for about 15 minutes and then observe.

III. What happens?
Does the change in temperature affect each type of protozoa differently or the same? If they move faster or slower with a different temperature, is the change in speed about the same rate for all three types? Help students write valid conclusions based on their new observations.

Feel free to write to us with information about how the experiment variations and expansions are received by your students. We appreciate all feedback.

NOTE: It’s vacation time, so next week’s Experiment Variation will be posted on Wednesday instead of Monday. Please forgive the delay.


Which Way Is Down?

The experiment in Chapter 5 of Biology Level 1 allows students to observe first-hand the effects of gravity and light on a plant’s root and stem growth, both in daylight and in darkness. The Lab Workbook experiment uses pinto beans as test subjects. But testing one type of bean does not allow students to draw conclusions about other types.

Let’s broaden the experiment and observe other types of of bean.

I. Prepare the lab notebook
Choose a different variety of bean for this experiment variation: navy beans or fava beans or kidney beans, for example. Have students create a new Objective and Hypothesis for the bean variety you choose to compare to the way a pinto bean grows.

II. Recreate the experiment steps with the new bean type
Follow each of the steps in the Workbook using the new type of bean and have students note specifically which type of bean is being used.

III. What happens?
Students will want to observe the new beans carefully, watching to see if this type of bean develops a hook on its root, for example. When the loose beans are cut open and examined, can students note differences in appearance even though the parts of the embryo may be the same? Students should observe and draw the changes to the taped beans over a period of several days and to the embryos of the loose beans. Then ask them to compare these records with the pinto bean records, and see what valid conclusions can be made.

Can they make lists of what is the same and what is different between the bean varieties? In doing this comparison, they are again using the classification skills that were the focus of the first Biology experiment.

Feel free to write to us with information about how the experiment variations and expansions are received by your students. We appreciate all feedback.