A classic- but easy experiment to show how plants are able to absorb water and nutrients through a process called transpirational pull.
By cutting the stalk of celery in half, you are able to see the capillaries that water and nutrients travel through to get to the rest of the plant.
The students will learn about transpirational pull by measuring food coloring traveling up a celery stalk.
(Insert Nutritional Obj. Here)
Mason Jar big enough to hold a celery stalk
Celery Stalk (with leaves) cut by teacher
Food Coloring (Blue and Purple have great results)
A paper and pencil for record keeping
Fill a mason jar about 1/3 full with water.
Add a several drops of food coloring, stirring with a spoon, until the water has developed a rich color of your choosing.
Show students the capillaries visible at the bottom of the stalk. Explain that this is where the water and nutrients travel through the stem to nourish the leaves.
Insert the celery stalk into the jar, with the stalk submerged in the water. Place the jar on a window sill, or somewhere it will receive sufficient light.
It may take overnight for the dye to reach the leaves. However, you can periodically check the celery stalk every hour and measure how far how the dye has traveled up the stalk. Keep a record for students of the time and how far the dye has traveled each hour. Make predictions with students, how much further will the dyes have traveled by the next hour? Will the leaves change color?
As the dye is notably traveling up the stem, explain to students that this process is called transpirational pull. Again show them the capillaries as they will be much easier to see with the dye in place.
This demonstrates how water is circulated to the plant. The water travels through the plant as the leaves are breathing.
Discuss with students what they need to help them grow by eating nutritious foods. Compare this to how plants get their water and nutrients from the soil. The things plants need to grow are sunlight, soil and water. Tell students that they will be able to see the water and nutrients in action as it nourishes the plant by doing a simple experiment!
Review with students how plants receive their nutrients. Have students write in a journal what they learned, they can draw pictures to demonstrate their knowledge.
Celery is also a refreshingly crunchy snack! “Ants on a Log” is a fun way to eat celery. Fill the celery with peanut butter and add raisons.