Integrated Science II

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Students were good sports about all of the factor label and metric system review. Much of this will help them throughout the rest of the year. Students determined their height in cm and then checked it on the “chart” outside the classroom. Many students also checked their “wingspan” to see if it came close to their height. Friday and Monday students will be working on designing an experiment to determine how the period of a pendulum varies. Photos to follow!

Today the class was “reminded” of all of the Factor Label work they have done in the past few years at the high school. Students worked in groups on some simple factor label problems in preparation for more serious ones to follow tomorrow.

Short periods on Friday meant that we covered the reading and activity over the two days. The class read an article about Semmelweis (Part I youtube) (Part II youtube) in the 1840s concerning “cadaver particles” and “child bed fever” deaths among women in a Vienna hospital. Questions concerning the article were to be answered in the science notebook for Tuesday.

Class today focused on steps the class took to conduct the microorganism activity. The method involved: developing a testable question, designing an experiment, conducting the experiment, gather results and making observations, proposing an explanation and then communicating the explanation.

Today students had a quiz that covered experimental design and the elements that make the results valid. A science scenario was presented that closely mirrored the style of questions that student will see on the PSSA exam.

Scientists are concerned about how students who wear contact lenses are taking care of their lenses. There is the chance that serious bacterial eye infections can develop if contacts are not cleaned properly. A group of 115 students were selected for the study. A new cleaning ingredient was tested to see if it made a difference in bacterial growth on the contact lenses.

Approximately 10% of the students were selected to receive no treatment and were given a solution for cleaning that contained no new active ingredient. Of the remaining students, ½ were given Cleaner A to use (full strength of the active ingredient) and ½ were given Cleaner B (90% of the active ingredient) Each week for 10 weeks the students’ lenses were swabbed and placed on nutrient agar in a petri dish. The dishes were placed in an incubator at 37^oC and checked every 12 hours for 3 days.

Computers were available for students to begin to write their lab report for the bacteria activity.

Day 2 of the microorganism lab. The petri dishes have been in the incubator since class time on 9-16-10 so today represents 96 hours of incubation. In a number of instances there were two types of bacteria growing where Friday there was only one. In most cases the size of the colonies increased. In all classes the control groups had no bacteria at all. Interestingly, the NBC Today show did a piece yesterday that looks as if we planned our lab around it! Quiz tomorrow on vocabulary and activity (25 pts).

Students observed growth (or not) in petri dishes after 24 hours. Observations were tabulated and dishes placed back in incubator for the weekend.

Enough said!

All good experiments have a control group.

Alaina M. making her observations.

Proper technique for swabbing the agar.

Students swab a sink drain in Room 170

Students collected samples around the school in an effort to answer the question, “What location at the school has the most bacteria?” They followed the procedure established by the class yesterday. Petri dishes were labeled and placed in an incubator at 37 degrees Celsius. We will check them tomorrow. Students began to write a letter to Dr. Greenholt that explains the reasoning behind the investigation and the results (when they have some).

In small groups the students worked on experimental design for the microorganism lab. After each group presented its procedure a clear and organized procedure was written that the entire class could (and will) follow on 9-16-10.

Petri dishes ready for nutrient agar.

Students began to design an experiment that could answer the question – “What locations in the high school have the most bacteria?” Groups were assigned. A discussion of criteria for a proper scientific investigation took place. Student also had fun reading this passage (we discussed how we observe and interpret) :

i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno’t mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt!