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Circulatory-Respiratory Connection


After finishing our study of circulation, we are wrapping up the exploration of the respiratory system this week.  While looking at the circulatory system, and in addition to our laboratory activities, the students conducted a dissection of pig and cow hearts.  This gave students a hands-on look at the “heart” of the circulatory system and enabled them to later create a working model of a heart chamber.  Video of the students in action can be seen by following this link:

Heart Dissection   

We are now beginning to explore the relationship between respiration and circulation in more depth through continued laboratory investigations.  The students have already completed separate lab activities looking at the effect of exercise on both heart rate and carbon dioxide production.  We are now ready to look at the interconnection of the two systems by observing how a change in one causes a response in the other – through an exploration of the mammalian diving reflex.  

The summative assessment for the Systems Unit will take place after the October break.  Students will begin developing a scientific investigation of their own creation to demonstrate the relationship between the circulatory and respiratory systems, similar to the examples we have practiced in class.  Students will work in small groups to design, carry out the investigation, and collect data.  They will then be asked to create graphs and draw conclusions based on this data, discussing how their experiment shows the interconnectedness of the systems.  The individual write-up will most likely occur at the beginning of the second week after the break.  I will post the specific summative assessment dates on the Walsh – Grade 8 Science website when they become more clear.

Systems Unit – The Digestive System

Human digestive system cross section

We have two guiding, essential questions that we will be referring to throughout the exploration of our systems unit:

  • How do the components of a system interconnect?
  • What are the implications of changing a component in a system?

We have been exploring the digestive system over the past few weeks and have been modeling and testing some of the components and their functions.  Below is a video of a model the students used to demonstrate the processes of mastication and peristalsis in the mouth and esophagus:

Mastication and Peristalsis Model

It was a messy and, I hope, memorable activity that attempted to model the beginning of our digestive system.  We analyzed the model in terms of strengths and weaknesses, as well as suggesting improvements to make the model more accurate.

The students also participated in a dissection of the digestive system of a pig – very similar to our own system.  This was also an engaging, albeit smelly, activity that gave the students hands-on exposure to the components we have been investigating.  Here is a video of some of the students in action:

Digestive System Dissection

We are now working on a summative assessment activity for the digestive system – a system analogy presentation.  This assessment asks students to identify and explain an analogy for the digestive system, and create a presentation to show their analogous system.  The project will be assessed in the following ways:

  • Knowledge and Understanding (identification of the structure, function, and behavior of the system and its components as well as the connection between components)
  • Transfer of Learning (creative, accurate, and detailed representations of the system and its components)
  • Communication of Learning (rationale for the analogous system and components)
  • Organization (time management and task prioritization)

Students are encouraged to use their own format for the presentation, including paper, physical, and/or digital models.  A guiding document and the scoring rubric are located on the student website.  The project should be completed entirely in class, with the students given three class blocks to complete their presentations.  The due date is Monday, Sept. 21 for all students.

Welcome to Grade 8 Science!


My name is Eamonn Walsh and I am happy to be back at ISM for another year of teaching science in our wonderful middle school.  I began teaching middle school science in upstate New York, U.S.A. before moving on to the International Community School in Addis Ababa, Ethiopia. This is my second year in Manila and I am excited to continue working with my talented colleagues and our impressive student body.

This purpose of this site will be to periodically give parents an overview of the Grade 8 Science program.  Additionally, the student website can be accessed by clicking the link at the top of this blog, or through the following link:

Walsh – Grade 8 Science

The student website provides details on the assignments and assessments that students complete, and should allow parents to be more informed of what their students are doing on a daily basis.   A link to the Grade 8 Science Class Expectations document can be found on the main student website page, or by clicking this link: 

Grade 8 Science Class Expectations   (you may need a Google account to view)

We began the year with a short unit on the nature of science, exploring what scientists do and what students should expect from the course throughout the year.  Our first activity, called the “Thirsty Candle,” asked students to use scientific skills to gain understanding of a common phenomenon.  A short video of the students in action can be seen below:

The Thirsty Candle

Students also completed an activity looking at how science is a work in progress and corrects itself, through an activity called “Dogs and Turnips.”  The activity also emphasizes the social side of science as students collaborate to determine the form of a sentence by progressively revealing words on cards.  A video of the students working is here:

Dogs and Turnips

We will be exploring the Systems unit next – I will provide an overview of that unit soon.  Please do not hesitate to contact me with any questions, comments, or suggestions.  I am looking forward to a great year working with your students!

Eamonn Walsh  –