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
Monday, July 07, 2008
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.
Posted by Rebecca W. Keller on 07/07 at 06:14 PM
Monday, June 30, 2008
Colorful Flowers
The way a flower’s stems and petals transport water is illustrated by Biology Level 1’s Chapter 4 experiment in the Laboratory Workbook. The workbook experiment demonstrates how the evaporative action from the flower’s petals pulls water up through the stem. As the colored water changes the white carnations, students visually see this process in action.
When we drink through a straw, the water flows up. But it can flow back down as well. Do flower stems behave the same way? This experiment variation will allow students to find out.
I. Prepare the lab notebook
Have students create a new Objective and Hypothesis for this variation.
II. Test the direction of water’s flow through a flower stem
To perform this experiment, have students prepare two small jars with colored water. Cut the flower off of a carnation and place that stem upright in a jar. Cut the flower from a second stem, but flip this stem upside down and place it in the other jar. Tape a small piece of white paper to the exposed end of each stem. Allow a sufficient amount of time for the flower’s capillary action to move the water through the length of the stem.
III. What happens?
Have students record the results they observe. (The paper on the exposed end of the upside-down stem will not show colored water.) What conclusions can students make about the way the stem’s capillary action works?
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 06/30 at 05:25 PM
Monday, June 23, 2008
Taking Away Oxygen in Photosynthesis
The importance of photosynthesis for life on earth is discussed in Chapter 3 of the Biology Level 1 textbook and Laboratory Workbook. The workbook experiment demonstrates the importance of the sun’s energy and water for most plant leaves to survive and produces observable changes that take place when these vary.
The basic “recipe” that yields the food plants manufacturer for themselves is:
Carbon dioxide + water + light = sugar + oxygen
The Lab Workbook experiment examines what happens to leaves when exposure to light, water and attachment to the plant varies. The same series of steps can be applied to learn what happens when air (which supplies the carbon dioxide) is blocked instead of light.
I. Prepare the lab notebook
Have students create a new chart with columns for the various states (such as uncovered in water) and with rows for 10 days of observation (see the chart they completed for Experiment 3 in their Lab Workbook).
II. Block the oxygen process
Instead of using paper to block the light from certain leaves, cover those leaves in plastic wrap to block the air (thus blocking the oxygen exchange process).
III. What happens?
Have students follow the format of the light-and-water experiment to write their Objective, Hypothesis and Observation Results. Review the table of observations with them and help them to arrive at valid conclusions. Had they remembered that oxygen was a critical component when they performed the light-blocking experiment and drew their conclusions?
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 06/23 at 02:04 PM
Monday, June 16, 2008
Asking “What Else?” Is Inside a Cell?
The complex nature and functioning of cells is discussed in Chapter 2 in the Biology Level 1 textbook and Laboratory Workbook. The lab experiment uses the observation and classification skills exercised in our first biology experiment to focus on the structures of cells.
Using Real Science-4-Kids books, you probably know that one of our favorite questions is “What if?” But now, have students use those sharpened powers of observation to expand the laboratory lesson with “What else?”
I. Prepare the Lab Notebook
Have students create a new chart with columns for “Bacteria,” “Plants,” and “Animals” like the one they completed for Experiment 2 in the Lab Workbook.
II. Outside Resources
Allow students to look on the Internet or in other resources such as an encyclopedia for further information about the complexities of cells.
III. What Else?
Have students use their outside resources and the diagrams they completed for the three types of cells to search for 10 additional things that are inside of a cell but are not mentioned in the RS4K text? What else is inside of a cell? Is each in all cell types? Students should note their observations on their chart and then see if they can make additional valid conclusions.
Are your students making the connections between honing their powers of observation and classification and the uses for these skills in understanding the real world? Feel free to write to us with information about how the experiment variations and expansions were received by your students. We appreciate all feedback.
Posted by Rebecca W. Keller on 06/16 at 02:17 PM
