Term 3 Week 7 - Youtube Video Demonstration of Cooling Curve of Napthalene

3E1 's Rekha and Harmeet

3E1's Elaine and Cheryl

The experiment was conducted with the Science (Physics) pupils at the subsequent weeks and there was a slight modification (direct heating) which allowed the solid-state napthalene to melt at a faster speed.

The Youtube video above shows the example without the use of datalogger temperature probes instead of the conventional method of mercury thermometer. It also shows the change in the napthalene as it cools down from a high to a low temperature. The solidification process is clearly captured in the video as napthalene cools down.

3E2's Zhao Wei and Ganeish

3E2's Fadeelah and Ashikin

3E2's Yunru and Nurul

The experiment has shown the full capacity of the use of dataloggers to measure fixed intervals of temperature instead of the conventional method. At the end of experiment, the teacher summaries the lesson by linking the observations to the cooling curve and to indicate the melting point/freezing point of napthalene.

Term 3 Week 6 - Practical Experiment on Transfer of Thermal Energy (4E1/5A1)

In the experiment that was carried out, the pupils were expected to produce the setup as shown above. Boiling water was to be poured into the stylofoam container and its temperature was to be recorded. Every 5 cm*3 of tap water is to be poured into till a total of 50 cm*3 of water was added into the container. Every time 5 cm *3 of water was poured, its corresponding temperature was recorded into a table of values.

Subsequently, a graph of temperature against the total volume of water added was plotted and a curve was obtained.

Precautions when conducting the experiment:-

1. Preparation of the experimental setup before obtaining the boiling water. Many pupils did not plan ahead of the requirement of the experiment and were anxious to fill their stylofoam container with boiling water. They did not fill their beakers with a total of 5o cm*3 of tap water first and were in the midst of thinking what to do while the temperature of the boiling water was dropping rapidly. They could have poured 5 cm*3 of water into the measuring cylinder and ensured that once they have obtained the boiling water to start recording the temperature.

2. Use of cloth to insulate the heat to reduce drop in temperature of boiling water. A cloth could be wrapped around the glass beaker before the start of the experiment.

3. The above preparation seeks to resolve the slow reaction time of the students as they need to improve on their peparation and planning skills.