Solar and lunar eclipses (with light box) (Item No.: P )

Transcription

1 Teacher's/Lecturer's Sheet Solar and lunar eclipses (with light box) (Item No.: P ) Task and equipment Information for teachers

2 Solar and lunar eclipses (with light hox) (Item No.: P ) Task and equipment Task How do eclipses of the moon or the sun occur? The aim of this ebperiment is to investigate how eclipses of the moon and the sun occur.

3 Equipment Position No. Material Order No. Quantity 1 Cuvette, double semicircular Light bob, halogen 12V/20 W PHYWE power supply DC: V, 2 A / AC: 6 V, 12 V, 5 A Additional material: Scissors 1 White paper (DIN A4) 2 Adhesive tape Sphere, nontransparent (of plasticine or marble) Compasses 1 d approb. 15 mm

4 Set-up and procedure Set-up Draw a circle with a radius of 8 cm on the right half of the sheet of paper. Fig. 1 Cut a strip of paper which is ebactly 1.5 cm 9.5 cm. Tape it to the outer edge of the cuvette so that light cannot pass through it. Fig. 2 Roll a small sphere (about 1.5 cm in diameter) from a piece of plasticine and place it on the circle. Put the inverted cuvette in the middle of the circle. Put the light bob with its lamp side nebt to the left side of the paper. Fig. 3

5 Procedure Connect the light bob to the power supply (12 V AC) and switch it on. Fig. 4 Move the sphere around the circle and observe the shadows which are cast on the sphere and on the cuvette. Move the sphere to the positions marked in the picture. In each position observe the occurring shadows and write down the results in the table in the report. Fig. 5 Lift the sphere about 2.5 cm when it is located in front of or behind the cuvette on the outside of the circle. Again observe the shadow formation. Compare this result with your previous observations and note your new results in the table in the report. Fig. 6

6 Switch off the power supply and put the light bob aside. Remove the paper strips and the remnants of the adhesive strips from the cuvette.

7 Report: Solar and lunar eclipses (with light box) Result - Table 1 (10 Punkte) Note your observations. Position of the sphere Observation of the shere's/cuvette's shadow Type of eclipses in front of the cuvette on the circle 1 behind the cuvette on the circle 1 lateral to the cuvette on the circle 1 in front of the cuvette at height of 2.5 cm 1 behind the cuvette at height of 2.5 cm 1 Evaluation - Table 1 (3 Punkte) Which three celestial bodies were roughly simulated in this ebperiment? Complete the following table. Ebperimental device Model for the celestial body light bob 1 cuvette 1 sphere (marble) 1

8 Evaluation - Question 1 (10 Punkte) A temporary eclipse of a full moon is called a lunar eclipse. Compare the following drawing with your ebperimental setup; complete the figure by adding the names on the celestial bodies simulated by the models and hatching the umbra of the earth. Evaluation - Question 2 (10 Punkte) Under which conditions does a lunar eclipse occur?

9 Evaluation - Question 3 (10 Punkte) The revolution of the moon around the earth takes approb. 29 days. Nevertheless, a lunar eclipse only about once a year to observe. Make an assumption based on these facts and your observations during the course of the ebperiment why we do not have a lunar eclipse during each revolution of the moon around the earth. Evaluation - Question 4 (10 Punkte) Which shadow is most important for the occurrence of an eclipse of the sun? Draw a similar sketch to the sketch in Question 1, but this time sketch what happens when an eclipse of the sun occurs.

10 Evaluation - Question 5 (10 Punkte) Under which conditions does an eclipse of the sun occur? Evaluation - Question 6 (10 Punkte) Why can the moon be completely eclipsed by the earth's shadow? In contrast, why can only parts of the earth's surface be eclipsed during a solar eclipse?

11 Evaluation - Question 7 (10 Punkte) The last total eclipse of the sun in Germany occurred on 8. September 1999; the nebt one will occur on 2. September With the help of your observations and your reflections on the occurrence of a solar eclipse, give reasons why we can observe a solar eclipse so rarely. Evaluation - Supplementary problem 1 (10 Punkte) During solar and lunar eclipses the shadows of the celestial bodies are always limited to circular areas. Which conclusion can be made from this about the propagation of light?