Charting Plant Growth Investigation
Note: This activity should take place over a span of one month.
Objective: Students will observe, evaluate, graph, and discuss the growth of the amaryllis bulb.
Materials Needed:
Amaryllis bulb (double blooming is best).
Pot and soil.
Sunlight and water.
Ruler for measuring.
Large class graph chart and/or individual student graph paper
Two colored crayons or pencils: green for leaf data and another color for flower data.
Notebook or journal for student notes.
Procedure:
1.Show the bulb to the class and discuss its parts and how it will be planted. Discuss the importance of reading and following the directions to guarantee success.
2.Discuss and decide on the best place to put the pot. Talk about the differences between direct and indirect sunlight and the affects it will have on the plant. Discuss the watering schedule.
3.Create a line graph to measure growth. This graph can be a class graph and/or individual student graphs. The horizontal axis is used to record the number of days, and the vertical axis is used to record the height in cm (or inches.) Plan on recording data for approximately 30 days or more. The length (height) of the leaves can grow in excess of 30 inches.
4.Begin recording data the first day (Day 1) as growth being ‘0 cm (or in.)’. Use green for leaf data and the other color chosen for the flower data.
5.Students take notes of previous activities including the planting procedure, care of the amaryllis, and how to set up the graph. Teacher may write key words on the board and have students write notes in their own words.
6.The class checks the amaryllis daily for growth activity. Students can take an active part in the care of the plant such as watering and turning the pot.
7.Once growth begins, with teacher guidance, students take turns measuring the length of the leaves, and, eventually, the bud. It is important to make sure to measure from the same spot on the bulb so that the data will remain accurate. The growth may be plotted on a large class graph for students to copy onto their own individual graphs.
8.After a few days growth, ask students to predict the rate of growth. Record their predictions, and later check back and see how accurate their prediction(s) were.
9.Determinethe rate of growth by subtracting the previous day’s (or week’s) length from the current length. Discuss how changes in the rate of growth can be evaluated by analyzing the angle of the line on the graph.
10.Once the flower bud starts to grow, compare the rate of growth between the leaves and the flower bud. Discuss why the rates of growth differ and what might cause one to grow at a faster rate than the other.
11.If the plant is placed near a window, observe if the plant bends toward the light. Discuss why this is happening.
12.Once the flower blooms, you can stop taking flower measurements. However, you may want to continue to measure the growth of the leaves to see if they will continue growing after the plant has bloomed.
Extensions:
Determine fractions of a whole by comparing the lengths at various stages to the final length.
Either as a class, or as individual students, use a spreadsheet program to input the data. Then have the program convert the data into a graph.
If the bulb sends up a second sprout, record its growth and compare it to the first.
Source:
MathScience360.org