Grade:
Time:
Topic:
Concept:
SOL:5.5
The student will investigate and understand that organisms are made of cells and have distinguishing characteristics. Key concepts include
- parts of a cell;
- five kingdoms of living things;
- vascular and nonvascular plants; and
- vertebrates and invertebrates.
Rationale:
Goals:
Objective:
Materials:
- wilted stalk of celery
- glass of water
- blue food coloring
- knife
Procedure:
Slice off a large piece of the bottom of the stalk of celery. Put five drops of blue food coloring in the glass of water. Place the celery in the water and let it stand overnight.
What do you notice about color of the celery stalk? What do you notice about the physical characteristics of the stalk? Have there been any changes?
Ask the students to record their observations in their science journals. Next, ask them to form an idea about why the celery changed after it was placed in the blue water.
Why?
Slicing off the bottom off of the celery stalk made sure that none of the celery cells were not closed off of dried out. The blue water then entered in the water-conducting tubes called xylem. These tubes follow the whole length of the stalk of the celery. Water leaves the xylem tubes and enters the cells up and down the celery stalk. When you slightly bend a plant, you notice that it stands up straight again after you let go. This is because every single plant cell is full of water. The water makes each cell firm, and all the cells combined give the plant a rigid feeling. A plant wilts when it doesn’t get enough water. The cells lose water and become limp. Then, the plant droops. The pressure of the water inside the plant is called turgor pressure.