In this slow motion video, a heavy medicine ball and a light ball are dropped from a ladder. Why do they hit the ground at the same time? In order to learn about cells and how they work, our 5th grade students are working towards a Project Based Learning initiative that will result in walk-in models of a plant and animal cell for parents to tour during parent-teacher conferences. One fifth grade class is in charge of building the animal cell, while the other is constructing a plant cell. In their classes, students were broken into groups, and each group was assigned a different organelle to research and construct out of recycled materials. Our 4th grade students even helped by collecting water bottles for us to reuse (as a result of a recent call with a penguin hospital in South Africa where they learned about the problems with plastic pollution in our oceans).
Groups just finished their research last week and have started construction this week. Some pictures of their work so far are below. Parents, community members, and the media will be invited to tour our mini-museum on November 24th from 12-4pm and 5-8pm. Both 5th grade classes have tested their hypotheses, which were listed in the last blog post. They had believed that adding salt water to plant cells would make them shrivel and die, and that the salt would cause the cells to release water. First, Mr. Soskil prepared slides for us using the thin film of cells that is between each layer of an onion. Next, we looked at the onion cells at lower magnifications to see the cell walls and how the cells were arranged. Then, we looked at the cells at 400x. With this magnification, we were clearly able to see the cell wall and the cell membrane, which was filled with water. The cell membrane and the cell wall were pretty close to each other. After we examined the cells, Mr. Soskil mixed some salt into water, and we used pipettes to decant salt water across the onion cells. We were clearly able to see a change in the cell membrane. The shape became less round, the area inside the membrane became smaller, and there was more space between the cell membrane and the cell wall. We will be examining our data, including these pictures next class to see what conclusions we can draw from this experiment.
In class, we were having a discussion about how salt that we throw on the ground to melt snow and ice often kills the plants that it lands upon. We are wondering why.
Following the scientific method, we did a little research and found that salt "sucks the moisture" out of plants. Below are some of our other research findings from class. Next class we are going to add some salt water to plant cells to see how they react. Our predictions can be seen below under step 3 (our hypotheses). Today we reviewed the scientific method and the way that scientists "do science" to learn about the world. Each student is making a poster to teach about the scientific method. Notes from class are below. Notes from class |
AuthorMr. Soskil and the South Elementary 5th grade science students Archives
February 2017
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