Monday, 4 May 2015

Energy Experiment

On the 29th of April, Room 10 sat eagerly waiting for some action in the science lab. We had been learning about energy, and it is one of our favourites because we get to do amazing experiments.  The first thing we learn is that what lots of us use the word respiration incorrectly; we use it to mean breathing, but that is wrong.  Here is what respiration really means.

Mrs. Dromgool, our science teacher, then explains that all food has chemical potential energy and it is just waiting to be used, scientists measure this by burning the food under some water and record the increase in the water temperature; today we were the scientists.

We started by getting an aluminum stand with a needle in it and we attached our food sample to the aluminium stand, our food sample was a mini marshmallow. 5ml of water in a test tube stood 7cm above the ground, after recording the temperature of the water, we put on our safety gear. Just so we don't get stray heat from the lit match we lit the marshmallow beside the test tube and then quickly slid it underneath the water. The marshmallow burnt really fast, and it was just a little too crispy for my taste. The water's temperature had risen by 11.5 degrees celsius, all that from just one little marshmallow.
Early in the next morning, we started calculating the energy in the marshmallow, we used the unit joules. Mrs. Hogg put up the equation for conversion on the board:
Most of just sat there confused. Mrs. Hogg explained that you times the temperature difference with the water in grams, 5 grams in our case, and times that by 4.2. You then take all of this and divide it by the weight of the marshmallow in grams, luckily someone measured this previously. Most of our answers were somewhere from 100 - 800 joules, that is a lot of joules for one marshmallow.

When we referred back to the packet of marshmallows, it turned out it had 4260 joules, now that is an energetic marshmallow. We were all startled by this value and started wondering why we were so off, we soon came to the conclusion that they, scientists, have access to precise equipment and controlled environments. Overall we had a lot of fun experimenting and figuring out how much energy a marshmallow has, we all loved being scientists.

By Aryan

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