We talked through the equipment and the setup of the practical, shortly before identifying the variables. In Science, the ‘Independent’, ‘Dependent’ and ‘Control’ Variables act as the guidelines to ensure a safe, fair test. We were going to be measuring the rate of cellular respiration in small organisms that were beans. Cellular respiration refers to the breakdown of glucose and other respiratory substrates to make energy-carrying molecules called ATP - this was vital information to keep in mind. Beginning our experiment, we heated the water bath at different temperatures on different tables so that we could measure the rate it would take for the organisms to respire depending on the different temperatures. How do we know when the organism has respired, you ask? Well, we connected a glass tube to the cork, covering the beans, and placed coloured liquid inside it. Once the organisms would respire they would consume the oxygen causing a decrease in the volume of gas which would then create suction drawing the coloured liquid down. To ensure that gravity and other factors were not the cause of the liquid moving downwards, we set up two apparatuses in every water bath, one was the control, meaning it did not have living organisms inside it, just marble chips. The other had beans inside. Once the practical was over, we recorded the temperatures and the distance the liquid dropped over the course of five minutes and then calculated the averages via spreadsheets. Through this practical, not only were we able to understand the effects of temperature on the rate of respiration but we were able to formulate the averages and put together data to support our discoveries.

Our final practical investigation examined the anatomy of the heart. As an aspiring cardiothoracic surgeon, this was a long-awaited lesson, not only to be able to see and dissect a heart, but also to understand its functions and its role in the astonishing cardiovascular system. We began by identifying the main aspects of the cardiovascular system and its components. First, we looked at the blood vessels: arteries, veins and capillaries. We established the reasons behind their structures and their functions. For example, we identified that the arteries are the largest of the three blood vessels because of the necessity of sufficient blood transportation around the body and that the thin configuration of the capillaries was because of its role in allowing efficient and facilitating gas exchange. Then, we watched an informative video explaining the structure of the heart and the functions of the many parts. This was followed by another video of an example dissection which guided us through to the practical.

Once I put on my gloves and was prepared, I held a sheep’s heart for the first time and it was quite cold. My partner and I placed it on the dissection tray. Then, I slowly made an incision vertically along the heart; this revealed the inner part of the smaller right ventricle. The right ventricle is responsible for pumping deoxygenated blood to the lungs. We could see the small heart strings, which held the valves, which act as doors into and out of the four chambers of the heart. This was an amazing experience and although it could be described as quite unsightly, it fueled my interest and passion for the heart; it was also extremely helpful for other students and me to be able to have an empirical view of the structures of the heart and the positions of all the parts. We even placed our fingers through the arteries finding out which chamber of the heart it would lead us to, which allowed us to correctly identify and label all the blood vessels.