Mrs. McDaid’s Science Blog

We will be putting what we know about the circulatory and respiratory systems together to design an experiment to test one variable that might affect heartrate.

For today, you will need

Designing exercise experiment

You will need to plan and conduct the experiment over the next two class periods.  You will need to turn in the Data Analysis Section of the the writeup for a Skills Grade (3.4).  Please use the attached rubric, so you know how you will be graded (and can self-score) and don’t forget to use your pink packet!

Exercise Rubric

DAY ONE: Here is the first picture, after 24 hours, of the plate that I inoculated with bacteria from my ear (YUCK!).  You will notice that the control is completely over grown with bacteria.  In the other 3 quadrants I have drawn circles that indicate the areas of inhibition of growth.  You should be able to identify the disinfectant that is the most effective and the one that is the least effective.  Also note, there is bacteria growing within the circle around the isopropyl alcohol dot, but the number of bacteria is reduced by about 50% compared to the control.  Click on the photo for a close-up view!

DAY TWO: After 48 hours, the area of inhibition of growth around the iodine has gotten smaller, and there are a number of colonies of bacteria that have started to grow within the circle.  The isopropyl alcohol is very similar to the what was seen yesterday, but it appears that the growth within the circle is a little thicker (meaning that it prevents the growth of some, but not all types of bacteria).  The circle around the band-aid strip is almost exactly the same.  This means that perhaps the chemical is more effective, or the band-aid is better able to hold on to the chemical, making it longer lasting.

DAY FIVE (AFTER THE WEEKEND): Even after 5 days, the antibacterial Band-Aid strip is still able to prevent the growth of bacteria to the same extent that it did from the very first observation!  The area of inhibition of growth around the iodine has gotten even smaller, and the alcohol is still preventing some growth, but is the least effective of the 3 chemicals that were used.  You should be making similar observations for you Petri dishes.

If you have any questions about your plates or the growth of bacteria please let me know.

This lab will be due on WEDNESDAY AND THURSDAY OF THIS WEEK.

In class today you will be using the microscope to search for and document bacteria in yogurt.  You will collect data, determine the type of bacteria you find, and then write a conclusion for this lab in a blog post.  This is just one way in which bacteria can be helpful.

You will need:  Lab – Bacteria in Yogurt

You are a member of Doctors Without Borders (MSF in French), a humanitarian organization that “provides aid in nearly 60 countries to people whose survival is threatened by violence, neglect, or catastrophe, primarily due to armed conflict, epidemics, malnutrition, exclusion from health care, or natural disasters. MSF provides independent, impartial assistance to those most in need.”  You have been asked, by your organization, to create a presentation to be given to the United Nations, in regards to health issues around the world.

With this in mind, you will need to create a presentation that clearly describe a disease that affects large populations, somewhere on the planet AND to provide a detailed plan on how that disease can be combated.

The instructions and rubric are here.

If you have any questions please let me know.  I would love to see you come to HOT so we can work through any problems together.

Today we will be completing a lab that shows how quickly bacteria reproduce – and we will be using beans to represent the bacteria!  Please complete the lab below, but make the graph on REAL graph paper so you can hand it in.  The graph will count towards your “Model Making” process standard.

Bacteria Beans Activity