Nirbhay Saxena (Y10): GCSE Biology practicals

The last term in Biology, we studied ‘key concepts’. These are fundamental ideas in Biology that we need to know for our GCSE exams in Y11. Furthermore, we need to know about ‘key practicals’ - hands-on experiments which help us understand how biological processes occur. 

One of these practicals was about using microscopes to look at onion cells. We used light microscopes to look at the structure of the cells. To enhance the visibility of the cells, we used Iodine, which stains the cell a yellowish colour. If you ever use iodine though, make sure to wear safety goggles. Iodine also stains for a very long time. In fact, once our Biology teacher, Mr Walsh got iodine on his hands and they were stained yellow for weeks! We put the onion skin on the ‘stage’ (which is where the object you wish to look at goes on the microscope) and used the coarse and fine focus to make it look clear. We saw something very similar to the first picture shown here.

It was cool to see the cell walls that we were learning about right in front of us. We could also make out some organelles like the nucleus, a black dot in the middle of the cell. 

This isn’t the only practical we’ve done so far in GCSE Biology. Our second practical involved potato chips. This was, of course, our practical on osmosis. We took our potato chips and dipped them in different solutions of sucrose (water + sugar). We put them in and waited 20 minutes. During this time, the potato chips would absorb some water through osmosis, which is when a liquid goes through a semi-permeable membrane. At the end, we measured the weight of each of the potato chips and noted it down. 

These practicals don’t just help to reinforce the understanding that we have about these biological processes, they provide us with meaningful insights into how science operates in the real world. It also allows students to have some fun by having the freedom of doing these experiments. It also helps us demonstrate the school’s HERO values and develop our IB learner profiles traits. We are being Responsible for our education through these practicals and we are showing that we are Inquirers and Thinkers by investigating these natural phenomena.

Nirbhay Saxena (Y10) 

Science subject prefect