# Can You See the Light?

### Summary

Students will plan and conduct an investigation by collecting, recording, and reporting data. Students will use the scientific method to conduct their investigations. Students will explore basic life processes. Students will explain phototropism and heliotropism.

### Coin Type(s)

- Quarter

### Coin Program(s)

- 50 State Quarters

### Objectives

- Students will plan and conduct an investigation by collecting, recording, and reporting data.
- Students will use the scientific method to conduct their investigations.
- Students will explore basic life processes.
- Students will explain phototropism and heliotropism.

### Major Subject Area Connections

- Science

### Minor/supporting Subject Area Connections

- Math

### Grades

- Fourth grade
- Fifth grade
- Sixth grade

### Class Time

**Sessions**: Four

**Session Length**:
45-60 minutes

**Total Length**:
151-500 minutes

### Groupings

- Whole group
- Pairs
- Individual work

### Background Knowledge

Students should have a basic knowledge of:

- Plant growth
- Photosynthesis
- Scientific method
- Measurement with a protractor

### Terms and Concepts

- Quarter
- Reverse (back)
- Phototrope
- Scientific Method
- Hypothesis
- Observation
- Conclusion
- Control
- Heliotrope

### Materials

- Potted sunflowers (short varieties)
- Sunflower Lab worksheet
- 1 cardboard box
- Scissors
- 1 overhead projector (optional)
- Kansas Quarter Reverse page
- 1 class map of the United States
- Grow lights
- Masking tape
- Yardsticks
- Markers
- Protractors
- Clock
- Chalkboard/chalk

### Preparations

- Make copies of the following:
- Sunflower Lab worksheet (1 per student)
- Kansas Quarter Reverse page (1 per student)

- Make an overhead transparency (or photocopy) of the Kansas Quarter Reverse page.
- Cut a hole in one side of the cardboard box approximately level with the top of the plant.

### Worksheets and Files

Lesson plan, worksheet(s), and rubric (if any) at www.usmint.gov/kids/teachers/lessonPlans/pdf/327.pdf.

**Session 1**

**Note: **This session will take place a few days before the lab itself begins.

- Display a small potted sunflower in bloom for the students. Explain to the students that, in a few days, they will be experimenting with sunflowers to learn more about how they interact with the sun.
- Lead a class discussion on the relationship between plants and the sun. Ask students to consider the ways in which plants use and depend on the sun for food and growth.
- Distribute one “Sunflower Lab” handout to each student.
- Display the cardboard box and point out the hole. Explain that the opening in the side of the cardboard box was placed level with the top of the plant.
- Explain that the box will be placed over the sunflower so that the opening is level with the top of the plant and that the sun will shine through the hole.
- Have the students read and discuss with a partner question 1 on their Lab handouts, then record their predictions. Remind the students that they need to include an illustration with their predictions.

**Session 2**

- As a class, review the student predictions and illustrations from their lab sheets. Discuss what might make the plant look different after being covered with the cardboard box.
- Lift the box off the sunflower. Direct the students to complete question 2 (illustrate the sunflower and summarize the changes they observe) on their lab sheets. Student responses should reflect that the sunflower bent toward the hole in the cardboard box.
- Have the students discuss why the plant is leaning toward the hole. The students should realize that the plant bent toward the opening in the cardboard box because that was the only source of sunlight. Explain that plants that grow or bend in response to light are called “phototropes.” Direct the students to complete questions 3 and 4 on their lab sheets.
- Have the students predict why a plant might bend toward the sunlight by completing question 5 on their lab sheets. Explain that a plant that bends toward the sun will be able to photosynthesize more efficiently than one that does not. If necessary, remind the students that photosynthesis is the process by which plants use sunlight as energy in creating food for themselves out of carbon dioxide and water. Direct the students to complete question 6 on their lab sheets.
- Describe the 50 State Quarters® Program for background information, if necessary, using the example of your own state, if available. Then display the transparency or photocopy of the Kansas quarter reverse. Locate Kansas on a classroom map. Note its position in relation to your school’s location.
- Identify the sunflower on the Kansas quarter. Explain that Kansas selected the sunflower to be on its coin not only because it is the state flower, but also because it has some very interesting characteristics. Explain that sunflowers are not only phototropes, they are also heliotropes. Heliotropes are plants that can turn themselves to stay exposed to the sun throughout the day. Direct the students to record this definition on question 7 on their lab sheets.
- Lead a class discussion on whether heliotropism is a positive or negative attribute for a plant. The students should realize that heliotropism is a positive attribute because it affords the plant more sunlight for photosynthesis (making food). Have the students answer question 8 on their lab sheets.
- Explain to the students that they will be conducting an experiment during the next session to determine how far a sunflower will turn during one day.

**Sessions 3 and 4**

**Note: **In these sessions, students will need to take measurements at set time intervals. The time intervals need to be at least 20 minutes but no more than an hour apart.

- Direct the students to complete the warm-up activity under the “Experiment” section of their lab sheets. Have the students discuss how heliotropism affects a plant’s ability to photosynthesize. Answer student questions.
- Remind the students that they will be conducting an experiment using a sunflower. In order to conduct the experiment, the students will simulate the sun with a grow light. Explain to the students that this lab aims to answer the question, “How far (in degrees) will a sunflower turn itself to face sunlight?” Have the students record this question on their lab sheets.
- Direct the students to write a hypothesis on the outcome of the experiment on their lab sheets.
- Organize the class into groups of three or four. Direct the groups to discuss their individual hypotheses. As the groups discuss, distribute a grow light, a potted sunflower, masking tape, two yardsticks, a marker, and a protractor to each group.
- Model the measurement process for the students. With a marker, place a dot in the center of the face of the sunflower. Then, hold the yardstick in front of the flower (parallel to the floor) and center it with the dot on the face of the flower. Lower the yardstick to the floor. Place one piece of tape at either end of the yardstick. Remove the yardstick and use masking tape to connect the two pieces of tape (which will form a straight line). Explain that this line will be the base line for all of the angle comparisons.
- Continue modeling the measurement process by ahving the students pretend that time interval 1 has passed and it is time to measure again (be sure to move the sunflower slightly in order to create an angle for measurement). Repeat step 5 but, when lowering the yardstick this time, be sure that it touches one end of the base line. Then, place a piece of tape at either end of the yardstick. When you connect the two pieces of tape, the second line will create an angle for you to measure. Using the protractor, measure the angle between the base line and the newest line.
- Remind the students that, when measuring, they should use the base line for measurement in each time interval.
- Direct the students to closely follow the procedure on their lab sheet. Allow an appropriate amount of time for group work.
- Reconvene as a class and have the groups share their conclusions. Record group data on the board and discuss factors contributing to discrepancies between group data.

### Differentiated Learning Options

- Take (digital) pictures of one group’s progress and save a record of their measurements. Students can use the data to create their own hypothesis and conclusion.
- Instead of using protractors for measurement, have students draw the movement of the sunflower over the course of the experiment.

### Enrichments/Extensions

As an individual project, direct students to represent all groups’ experiment data graphically and write an expository paper on why group results may have varied.

Use the worksheets and class participation to assess whether the students have met the lesson objectives.

**Discipline**: Math

**Domain**: 4.MD Measurement and Data

**Grade(s)**:
Grade 4

**Cluster**: Geometric measurement: understand concepts of angle and measure angles

**Standards**:

**4.MD.5.**Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and understand concepts of angle measurement.- An angle is measured with reference to a circle with its center at the common endpoint of the rays, by considering the fraction of the circular arc between the points where the two rays intersect the circle. An angle that turns through 1/360 of a circle is called a "one-degree angle," and can be used to measure angles.
- An angle that turns through n one-degree angles is said to have an angle measure of n degrees.

**4.MD.6.**Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure.**4.MD.7.**Recognize angle measure as additive. When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts.- Solve addition and subtraction problems to find unknown angles on a diagram in real world and mathematical problems, eg, by using an equation with a symbol for the unknown angle measure.

**Discipline**: Mathematics

**Domain**: 3-5 Number and Operations

**Cluster**: Compute fluently and make reasonable estimates.

**Grade(s)**:
Grades 3–5

**Standards**:

In grades 3–5 all students should

- develop fluency with basic number combinations for multiplication and division and use these combinations to mentally compute related problems, such as 30 × 50;
- develop fluency in adding, subtracting, multiplying, and dividing whole numbers;
- develop and use strategies to estimate the results of whole-number computations and to judge the reasonableness of such results;
- develop and use strategies to estimate computations involving fractions and decimals in situations relevant to students' experience;
- use visual models, benchmarks, and equivalent forms to add and subtract commonly used fractions and decimals; and
- select appropriate methods and tools for computing with whole numbers from among mental computation, estimation, calculators, and paper and pencil according to the context and nature of the computation and use the selected method or tools.

**Discipline**: Mathematics

**Domain**: All Problem Solving

**Cluster**: Instructional programs from kindergarten through grade 12 should enable all students to

**Grade(s)**:
Grades 3–5

**Standards**:

- Build new mathematical knowledge through problem solving
- Solve problems that arise in mathematics and in other contexts
- Apply and adapt a variety of appropriate strategies to solve problems
- Monitor and reflect on the process of mathematical problem solving

**Discipline**: Science

**Domain**: 5-8 Content Standards

**Cluster**: Life Science

**Grade(s)**:
Grades 3–5

**Standards**:

- Structure and function in living systems
- Reproduction and heredity
- Regulation and behavior
- Populations and ecosystems
- Diversity and adaptations of organisms

**Discipline**: Science

**Domain**: 5-8 Content Standards

**Cluster**: Science as Inquiry

**Grade(s)**:
Grades 3–5

**Standards**:

- Ability necessary to do scientific inquiry
- Understand scientific inquiry