The Weather Glass

We keep a special glass out on the balcony of our apartment. It is my sister's glass. She wants to be a meteorologist when she gets older. A meteorologist is a person who studies the weather.

Each morning, my sister wakes me up. We go out to the balcony to measure how much water is in the glass. The glass has horizontal lines drawn all the way up its side. The lines are there so that we can measure how much water is in the glass.

On most days during the summer, the water level in the glass gets a little lower each day. But sometimes a rainstorm comes through town. Our apartment is on the top floor, so there is no roof above our balcony. When the rainstorms come, the water level in the glass gets higher.

One winter, we had a blizzard. The glass filled up with snow.

“Hmm” my sister said. “I cannot measure this.”

“Why?” I asked.

“Well, there is space between the snowflakes. But I do not know how much space there is. I will have to figure out another way to measure this.”

My sister brought the glass inside. After a while, all the snow had turned to water. Then she measured the amount of water in the glass.

My sister has a notebook. Each day, after we look at the glass, she writes down the measurement in her notebook. Then she writes down the date. She also writes down what the weather was like that day.

At the end of each season, my mom and dad make a special dinner. It is the weather dinner. During the weather dinner, my sister brings her notebook to the table. She tells us how much rain fell that season, or how dry the season was. Then she tells us how this season was wetter or drier than the same season last year. She has been keeping notebooks for a few years.

My sister says that when she goes away to college, she will give me her notebook. Then it will be my turn to measure the weather each day!


Level or straight across.

Use different tools to collect data about the properties of objects.

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  1. Why does the water level in the glass get lower during the summer?
    [anno: The water level in the glass gets lower during the summer because the water in the glass evaporates.]
  2. Why did the sister bring the glass inside after the blizzard?
    [anno: The sister brought the glass inside after the blizzard because she could not tell how much water was in the glass. The water had frozen into snowflakes. When she brought the glass inside, the snow melted, and she could measure the water in the glass.]
  3. Imagine that the sister is taking measurements of water for a week. At the beginning of the week, there is a big rainstorm. Then the rest of the week is hot and dry. How might the measurement at the beginning of the week be different from the measurement at the end of the week? Why?
    [anno: Answers may vary but could include that the rainstorm would cause the water level in the glass to rise by a certain amount. After many days of hot and dry weather, the water might evaporate and return the water level to the same place it was at the beginning of the week.]