Monday, August 11, 2008
Making an Underwater Ecosystem
The Chapter 10 experiment in Biology Level 1 instructs students on how to create a closed ecosystem so that various cycles can be observed. To vary the Chapter 10 experiment presented in the Lab Workbook, students can create a simple underwater ecosystem.
I. Prepare the lab notebook
Students should make a grid for drawing the results they observe or prepare a section for notes on observations over a number of weeks. The experiment Objective will be essentially the same.
II. Create the underwater ecosystem.
The water ecosystem should be created in a large jar or small aquarium that can be sealed. Students will add brine shrimp, algae and phytoplankton to non-chlorinated water (such as distilled water). They can get brine shrimp, algae, and phytoplankton at most aquarium or fish stores. They will want to measure and record the amount of each component they put into the jar with water, and then seal the jar. Observe what happens to the shrimp. Students may want to vary the amounts of shrimp, algae and phytoplankton they put in the jar to see how those variations affect the balance of the ecosystem. They should carefully keep track of all observable changes.
III. What happens?
What happens to the shrimp? What changes can be observed when each component of the ecosystem is changed. Help students write valid conclusions based on their 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.
Posted by Rebecca W. Keller on 08/11 at 12:48 PM
Monday, August 04, 2008
From Caterpillar to Butterfly
Biology Level 1’s Chapter 9 experiment for takes students through the life cycle of a butterfly, from caterpillar (larval stage) to cocoon (pupal stage) 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 type of butterfly 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 butterflies simultaneously so that they can observe differences and similarities directly instead of relying on their drawings and notes. Since completion of each metamorphosis may take weeks, observing two types at the same time allows completion of the comparison in a more reasonable period of time.
I. Prepare the lab notebook
Students will use basically the same Objective of observation since they are recording changes. However, for this second type of butterfly, students may wish to create a Hypothesis about whether the second type will develop differently from the first. This will be easier if they are able to read further information about the specific caterpillar types they are observing.
Resources for purchasing butterfly kits included in the Teacher’s Manual are:
http://www.wardsci.com and http://www.insectlore.com
II. Follow the same experiment steps as provided in the Lab Workbook.
Be sure students accurately label, at least by description, the caterpillar(s) they are observing. If you have purchased a kit, their notes should include the butterfly’s proper name. They will want to draw periodically the changes they observe in addition to recording the physical changes they see each week.
III. What happens?
What differences in size and appearance can be described? Is the second larvae eating the same kind of food? Does the amount of food eaten in a similar period differ? Did the second species begin some changes sooner or later in the life cycle? Are there differences in how the cocoons were constructed? 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.
Posted by Rebecca W. Keller on 08/04 at 01:15 PM
Tuesday, July 29, 2008
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.
Posted by Rebecca W. Keller on 07/29 at 09:31 AM
Wednesday, July 23, 2008
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.
Posted by Rebecca W. Keller on 07/23 at 12:08 PM
Monday, July 14, 2008
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.
Posted by Rebecca W. Keller on 07/14 at 05:37 PM
