Science 8

Core Unit: The Earth and Space

Unit overview

Space exploration has an appeal which is hard to resist. The desire for knowledge of what is beyond the bounds of the Earth's atmosphere is strong. Radio-astronomy, the SETI project, the Apollo, Soyuz, Skylab and shuttle missions, the Venera, Pioneer, Voyager, and Mariner probes all have given people a glimpse of the extraterrestrial. Questions of the structure of space, the characteristics of stellar and planetary objects, and how humans inquire into these phenomena form the basis of this unit.

This unit is related to the core grade 6 unit Exploring Space. Some of the objectives follow from the objectives of that unit. The outline of the grade 6 unit should be read and the students' concepts assessed according to the objectives of that unit.

Science writing and reading activities, as discussed in this Guide, should be incorporated into each lesson. Writing helps students make sense of what they are seeing and reading, and helps them adjust the way they look at the world. Students come into science classes with an understanding of how things work. Often their understandings are not the same as the way scientists understand events or ldo not correspond to what they themselves observe. Reflective writing can help them reevaluate their ideas and schemata. Reading newspapers and journals is an important source of ideas, and reporting on the activities of science class by writing advertisements, reports, and stories are strategies through which students may refine their understanding of the concepts of science and develop their ability to communicate through the written word.

Science challenge, as described in this Guide, is meant to extend students' critical and creative thinking abilities in the context of the science concepts being studied. Activities involving science challenge should be incorporated into science lessons in each unit. The challenge is intended to give each student a chance to investigate an area of interest in more depth than would be possible for all students in a class to do. Science challenge is a key strategy for bringing the Adaptive Dimension to the classroom, and for encouraging independent learning. Many of the suggested activities in this unit are Science challenge activities.

Factors of Scientific Literacy that should be emphasized

Concept development

Foundational and learning objectives for Science and the Common Essential Learnings

Understand the movements of the planets and other bodies in the solar system .
1. Describe how the rotation of the Earth produces day and night .
2. Account for the differences of day length in midsummer and in midwinter.
3. Explain why the Sun has a stronger heating effect in summer than in winter in the northern hemisphere.
4. Compare the speed and the length of path of the orbits of the planets .
5. Explain the retrograde motion of the planets in the sky.
6. Identify by sight the planets Venus, Jupiter, and Mars .
Recognize the conditions which govern life in space.
1. Study the physiological and psychological experiences of astronauts and cosmonauts in the skylab and spacelab programs.
2. Research the successes and failures of the space shuttle program.
3. Consider the distances and times involved in interplanetary and interstellar space travel .
4. Investigate ideas about space exploration expressed in science fiction .
Reflect on the matter of interstellar travel.
1. Determine how distances to stars are estimated .
2. Examine the distribution of stars in the sky.
3. Identify the various types of objects and groupings of objects in interstellar space.
Provide for students' active involvement in decision-making about space exploration . (TL )
1. Generate alternatives to technological innovations in the study of space.
2. Participate in debate about the support of space exploration.
3. Examine the place of space science and technology in North American science.

Suggested activities

Note: Many of the resources listed in Science: An Information Bulletin for the Middle Level - Key Resource Correlations describe activities or ideas for activities.

Build a model to show why Venus is sometimes seen as a bright "morning star", rising slightly ahead of the sun, sometimes as an "evening star" setting shortly after the sun but never high in the sky during the middle of the night.
Factors: B15, B24, C18, F7, G3
Objectives: 1.4, 1.5
Assessment Techniques: observation checklist, oral assessment
Instructional Methods: model building, concept formation
Build a model that shows the tilt of the Earth with respect to the plane of its orbit. Use the model to show why there is stronger heating in the northern hemisphere during the summer than during the winter. Use the model to explain why the Tropic of Cancer is at 23° north latitude and why the Arctic circle is at 67° north latitude. Show why there is 24 hours per day of daylight north of the Arctic circle during the summer.
Factors: B15, B24, C18, F3, G3
Objectives: 1.1, 1.2, 1.3
Assessment Techniques: rating scale, oral presentation, short answer test items
Instructional Methods: model building, problem solving
Start an astronomy club. Some activities of the club might be to:
- telecommunicate with others interested in astronomy ;
- plan field trips or special events;
- photograph the moon; or,
- invite guest speakers.
This club could be operated as part of the regular instructional program or as an extracurricular activity open to students in other grades. If there is a local astronomy club, opportunities might exist for guest speakers and cooperative efforts.
Factors: A1, C3, B5, B25, C18, D8, E1, F3, G7
Objectives: 1.6, 3.2, 3.3, 4.1
Assessment Techniques: self assessment, presentations
Instructional Methods: field observations, reflective discussion, explicit teaching, problem solving
Create a scale model of the distances between planets in the solar system. Assign students the responsibility to find out the distances involved, or use the values on the chart accompanying this activity.

Planet Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto Planet X

Distance
(in A.U.) 0.39 0.72 1.00 1.52 5.20 9.52 19.60 29.99 39.37 ?

Relative
Diameter 4 9 10 5 112 94 37 38 5 ?

Use string to represent the scaled distance from the sun to each planet. Tape a tag on the string to indicate where each planet would be located on the scale you are using. Use the actual distance between Pluto and the Sun to determine what scale should be used so that the model can fit within the room available to the students. This calculation is easier for students if they use the distance in astronomical units (A.U.) rather than the distance in metres. 1 A.U. is the mean distance of the Earth to the Sun.
Make spheres to show the planets in their relative sizes. Again ask the students to calculate the scale needed so that the model of Jupiter is a reasonable size. Actual diameters in metres or the relative diameters from the chart can be used. How large would the diameter of the Sun be on a scale that places the Earth at a diameter of 10 units? Why is there a Planet X in the chart?

These spheres can't be used with the string model of the distances between planets since the scales are different. Ask the students to calculate the size of the sphere models of the planets if they were built to the same scale as was used to make the distance model.
In the previous activity, the value for the distance from the sun to Neptune, in astronomical units, is 29.99. The value given for Pluto is 39.37 astronomical units. During part of Pluto's orbit, the planet is inside the orbit of Neptune. In other words, it is closer to the sun than Neptune. If that is the case, ask students to research this to determine how the values of 29.99 and 39.37 are derived.
Debate the issue "The development of the space shuttle has benefited human life on Earth."
Calculate how long it would take the current space shuttle to reach the moon, Mars, Jupiter and the edge of the solar system. What are some of the problems associated with missions of these lengths?
Investigate how the characteristics of the planets correspond to the names of the Roman gods after which they were named? Who was the god Mercury? Why was his name given to the planet?

What are the names of Jupiter's moons? Why were they given these names? Is there a name for our moon, other than "Moon"?
Where is the North Star? Why was the North Star important for the Aboriginal peoples of North America? Some people say that the North Star is in the constellation called the Little Dipper. Others say it is in the constellation called Ursa Minor (The Small Bear). Can a star be in two constellations at the same time?
Research the construction and use of medicine wheels by the various Plains Indian peoples. What signposts in the sky did they rely on? What did these signposts point to?
Why does the sun rise in the southeast during the winter, in the east during spring and fall and in the northeast during the summer? Does it ever change the direction in which it sets?
Observe the position of the moon in the sky for at least one month. What patterns govern its motion and position?
Why is there a full moon only when the moon rises as the sun sets? What is a "blue moon"? What makes a harvest moon appear to be red?
Create a device to measure the apparent diameter of the moon as it rises. Compare this diameter to the diameter measured when the moon is high overhead in the south. How can you explain the results of your measurements?
If you were outside during January, and saw the constellation Orion in the sky, which direction would you be facing? How could this information be of some use to you? Why isn't Orion visible in the sky during the summer?

Planet	Mercury	Venus	Earth	Mars	Jupiter	Saturn	Uranus	Neptune	Pluto	Planet X
Distance (in A.U.)	0.39	0.72	1.00	1.52	5.20	9.52	19.60	29.99	39.37	?
Relative Diameter	4	9	10	5	112	94	37	38	5	?