Read the case carefully and answer the questions that follow:
During a science activity, a group of students decided to make a simple water clock using a used transparent plastic bottle. They cut the bottle into two parts and made a small hole in the cap using a drawing pin. The upper part of the bottle was then placed in an inverted position over the lower half. They filled the upper part with water and added a few drops of colour so that the water level could be seen clearly.
As the water started dripping into the lower part, the students used a watch to mark the water level after every one minute. After all the water had dripped down, their water clock was ready. To use it again, they poured the water from the lower part back into the upper part. They observed that every time the water level reached a marked line, one more minute had passed.
As the water started dripping into the lower part, the students used a watch to mark the water level after every one minute. After all the water had dripped down, their water clock was ready. To use it again, they poured the water from the lower part back into the upper part. They observed that every time the water level reached a marked line, one more minute had passed.
1. Explain how the students constructed the simple water clock and how it was used to measure time.
The students first took a and cut it into two parts. They made a and placed the upper part in an . They then filled the upper part with water and added colour to make the water level easier to observe.
As the water dripped through the small hole into the lower part, the students used a watch to . These markings were then used as time intervals. When the water was poured back into the upper part, each marked level indicated that had passed.
2. Why did the students add colour to the water and make markings on the lower bottle? Explain how these helped in using the water clock.
The students added a few drops of to make the water level easily visible. This helped them observe the changing level of water clearly as it collected in the lower part of the bottle.
They then used a watch to mark the water level . These marks provided reference points for measuring time. When the water level reached the next marked line, had passed, allowing the students to estimate the elapsed time without continuously looking at the watch.
3. Suppose the students pour the collected water back into the upper part of the bottle after completing the activity. Explain how they can use the water clock again to measure time.
The students can from the lower part back into the upper part of the water clock and begin the measurement again. As the , it gradually collects in the lower part.
They can observe the water level as it rises. Every time the water reaches , one more minute has passed. Thus, the marked levels act as a simple time scale, allowing the water clock to be used repeatedly.