Lag activity Edlipses The purpose of this activity is to determine how differing distances between Earth and the Moon will affect solar eclipses. LLEETERTL T View of Sun from Earth Use the tool from Lesson 2 (shown in Figure 3-4) to complete the table below. The position to the right of the Moon in Figure 3-4 is position 1, and the position numbers progress counterclockwise. LU ] (not drawn to scale) i B Figure 3-4 This tool from Lesson 2 allows you to observe what a solar edipse looks like depending on the Moon's position in its orbit. Position | Angular Size of Orbital Radius Total or Annular Number | Moon (in degrees) of Moon (in km) Eclipse? 00| ~N | W W N - In general, how does the angular size of the Moon appear to vary with changes in its orbital radius? According to the table, ANNULAR | TOTAL (circle one) solar eclipses seem more likely. In which position would the eclipse be least noticeable to observers on Earth? Explain your reasoning. 11. For each pair of objects in the table below, estimate the ratio of the distance between the objects to their size. Obtain the distances for your estimates from the order of magnitude tool shown in Figure 1-3. List the pairs from the smallest to the largest ratios. 10 billion light-years {10** m) [ '3 [E .o Zoom in (x 0.1) Figure 1-3 Shown here is the order of magnitude tool from Lesson 3. Use the distance given at the various orders of magnitude to make your esti- mates for the questions in Lesson 3. Object Approximate Size Distance to Distance/Size Milky Way Galaxy 100,000 ly Andromeda Galaxy = Sun 108m Alpha Centauri = Jupiter 107 m Sun= Earth 106 m Moon = 12. Which distance to size ratio is the largest? The smallest? Which two of the distance-size ratios from question 11 are most similar in order of magnitude? tas activiry Motion and Gravity The purpose of this activity is to learn how the radius and mass of a planet affect the gravitational pull it exerts on another mass and to demonstrate the difference between mass and weight. Use the tool from Lesson 2 (shown in Figure 6-4) to determine both the person's largest and smallest possible weights. Record your results in the table below. h L LU N B B.l]-! kg LT LR LD | N Radius of planet [LEETRLTIET T 3 1.0 | Resen L AN Figure 6-4 This tool from Lesson 2 determines the weight of a mass on planets of different radii and mass. Person's Mass (kg) Radius of Planet (R, ) Mass of Planet (M, ) Person's Weight (N) 80 _ Largest: 80 Smallest: Which extremes of the radius and mass of the planet were needed to get the largest possible weight for the person? Which extremes of the radius and mass of the planet were needed to get the smallest possible weight for the person? 9. How far away will each of the galaxies in question 8 be after that amount of time has passed? LESSON 3 Use the tool shown in Figure 21-3 for these questions. 10. Using a value of 50 km/s/Mpc for the Hubble constant, what is the age of the universe? - The universe today Age of universe 13.00 Gyr | TODAY nstant (Ho) IS 150 75 kmis/Mpc Figure 21-3 This tool from Lesson 3 determines the age of the universe for varying values of Hubble's constant. 11. How would a higher value for the Hubble constant affect the calculation of the age of the universe? A lower value? 12. If the value of the Hubble constant were 50 km/s/Mpc, what would be the farthest distance away at which we could see an object? Explain your answer. s it possible that there are objects farther away that we cannot see? Explain your answer. Lag acnivity Hubble's Law The purpose of this activity is to show how we can use Hubble's law to determine the distance to galaxies, their recessional velocities, and the age of the universe. Use the graph in Figure 21-4 to determine the dlstance (In Mpc) to a galax'y that haS a reces- The slope of this line is Hubble's constant sional velocity of about 400 km/s. 13 A F o o b Lo 1] v] [+ 4 Use the graph in Figure 21-4 to determine the recessional velocity (in km/s) of a galaxy that is about 14 Mpc away. 6 L 10 12 14 18 Distance from Earth (Mpc) Line slope = 65 km/s/Mpc Figure 21-4 This tool from Lesson 1 determines Hubble's constant, the slope of a Hubble's law plot. The age of the universe T, in billions of years, can be approximated by the following expression: T = 1000/H where H is Hubble's constant. Use the value of the Hubble constant in the graph in Figure 21-4 to determine the age of the universe. T=__ = billionyears