To identify different forms of energy produced by the sun.
This lesson was developed by the Challenger Center as part of NASA's MESSENGER Mission, of which Science NetLinks is a partner.
In this lesson, students will perform simple experiments that will help them to explore unseen energy produced by the sun. During the course of this lesson, students will be exposed to these concepts: the sun produces both visible and invisible forms of energy; the light we see is visible energy produced from the sun reflected off surfaces; ultraviolet energy emitted from the sun can produce skin burns and cancer; and there are ways of blocking ultraviolet radiation. Refer to the Science Overview of the lesson for a summary of the science content relevant to the activities in the lesson. Refer to the Lesson Overview for a more detailed explanation of what students will learn from the lesson.
Children's strategies for learning more about their surroundings improve as they gain experience in conducting simple investigations of their own and working in small groups. At this level, they should be encouraged to observe more and more carefully, measure things with increasing accuracy, record data clearly in logs and journals, and communicate their results in charts and simple graphs. Time should be provided to let students run enough trials to be confident of their results. Investigations should often be followed up with presentations to the entire class to emphasize the importance of clear communication in science. Class discussions of the procedures and findings can provide the beginnings of scientific argument and debate.
Students' investigations at this level can be expected to bear on detecting the similarities and differences among the things they collect and examine. They should come to see that in trying to identify and explain likenesses and differences, they are doing what goes on in science all the time. What students may find most puzzling is when there are differences in the results they obtain in repeated investigations at different times or in different places, or when different groups of students get different results doing supposedly the same experiment. That, too, happens to scientists, sometimes because of the methods or materials used, but sometimes because the thing being studied actually varies.
Studies show that there are some limits on what to expect at this level of student intellectual development. One limit is that the design of carefully controlled experiments is still beyond most students at this age. Others are that such students confuse theory (explanation) with evidence for it and that they have difficulty making logical inferences.
In any case, some children will be ready to offer explanations for why things happen the way they do. They should be encouraged to check what they think against what they see. As explanations take on more and more importance, teachers must insist that students pay attention to the explanations of others and remain open to new ideas. This is an appropriate time to introduce the notion that in science it is legitimate to offer different explanations for the same set of observations, although this notion is apparently difficult for many youngsters to comprehend. (Benchmarks for Science Literacy, pp. 10-11.)
Finally, when engaged in experimentation, keep in mind that students of all ages may overlook the need to hold all but one variable constant. Another example of defects in students' skills comes with the interpretation of experimental data. In general, research shows that students have difficulty interpreting covariation and noncovariation evidence. For example, students tend to make a causal inference based on a single concurrence of antecedent and outcome or have difficulty understanding the distinction between a variable having no effect and a variable having an opposite effect. Furthermore, students tend to look for or accept evidence that is consistent with their prior beliefs and either distort or fail to generate evidence that is inconsistent with these beliefs. These deficiencies tend to mitigate over time and with experience. (Benchmarks for Science Literacy, p. 332.)
Ideas in this lesson are also related to concepts found in these Common Core State Standards:
- CCSS.ELA-Literacy.RI.3.3 Describe the relationship between a series of historical events, scientific ideas or concepts, or steps in technical procedures in a text, using language that pertains to time, sequence, and cause/effect.
- CCSS.ELA-Literacy.RI.4.3 Explain events, procedures, ideas, or concepts in a historical, scientific, or technical text, including what happened and why, based on specific information in the text.
Have students take part in the discussion presented in the Warm-Up & Pre-Assessment section of the Sensing Energy lesson plan. Finding out what students know about light will serve as a basis for exploring two other aspects of energy from the sun—heat and ultraviolet (UV).
For the MESSENGER mission to Mercury, it is important to study these different forms of energy—particularly for the preservation of the spacecraft, which will be exposed to their very dangerous effects when it flies outside the Earth's protective atmosphere.
Have students perform the activities in the two-part Procedures section. For Part 1, students will use Ultra-violet Detection Beads to look for and analyze changes in the color of the beads when exposed to different sources of light. For Part 2, small groups of students will put UV beads in a number of open film cannisters (under different conditions) and place them in the sun. Each group should fill out the Student Worksheet #1 to record and later discuss their findings with the rest of the class as part of the Discussion and Reflection phase of the lesson.
For the Assessment section of the lesson, have students design their own test to show how the UV beads respond under different conditions.
Finally, encourage students to make connections between what they have learned about the sun's energy and the MESSENGER mission. Moreover, have them think about and discuss different ways that the MESSENGER spacecraft can be protected from the harmful effects of the sun's radiation. A MESSENGER model can be constructed beforehand to aide in this discussion.
Color Burst helps students gain experience in asking questions and conducting inquiry by exploring the separation of colors in water and other solvents. It also encourages students to communicate and share findings of their investigations.
The focus of the Does Soap Float? lesson is scientific inquiry. In the lesson, students form hypotheses and carry out an investigation in order to answer a central question.
The experiments in Sink It are designed to encourage student skills in experimental design, testing simple hypotheses, and grouping objects by common characteristics.
For students who know about other planets, ask them to speculate about how much of the sun's power reaches them. Ask about visible light, heat, and UV radiation. You may want to mention here the other forms of solar energy discussed in the Science Overview, which includes gamma, X rays, infrared, and radio waves. Study questions (or research topics) may include:
- How would the sun's energy be different on different planets such as Mercury or Pluto?
- What features about the other planets make them different from our planet?
- Why are those features important when we think about light, heat, and UV radiation?
To make this lesson more relevant to students' knowledge of biology in the early grades, explain how insects use their ability to sense ultra-violet radiation. Butterflies and bees see ultraviolet light as a distinct color that makes certain markings on flowers very vivid to them and guides them to the nectar tubes.