11-14-2016 Monday

Science Log 5 Monday, November 14: How is the surface of the moon different than the surface of the Earth? How is it the same? Explain how this makes it difficult to study craters on the Earth.

25. Multimedia of crater formation Three crater-formation animation Crater Formation on the Moon Scientists who study the Moon have suggested a model for the origin of the maria. They think the maria probably started as giant impat craters, called basins, but then something happened after impact. This is their idea. A large impactor made a huge crater called a basin. The force of the impact shattered the Moon’s mantle deep into the interior. Much later (hundreds of millions of years), magma deep in the Moon flowed up through he cracks in the bottom of the basin, filling them with lava from below. The lava hardened into basalt, a smooth, dark rock that formed the surfaces of the maria we see today. A mare is a large flooded crater.

Impact theory Moon photo Master G Dark maria can be visualized as a complex of circles (basins). Some of the mare basins are formed by overlapping impact basins.

26. Focus Question FQ 6.1 page 66 Are Moon craters the result of volcanoes or impacts? Answer your focus question, site information from experiments.

Reading: “Craters: real and simulated” Is it a simple or complex crater? How old do you think it might be? Why? Why do you think there are so few craters on Earth and so many on the Moon?

Reading: “Craters: real and simulated” Is it a simple or complex crater? Simple How old do you think it might be? Why? Why do you think there are so few craters on Earth and so many on the Moon?

Reading: “Craters: real and simulated” Is it a simple or complex crater? How old do you think it might be? Why? Why do you think there are so few craters on Earth and so many on the Moon?

Reading: “Craters: real and simulated” Is it a simple or complex crater? How old do you think it might be? Why? Not to old because you can still see where the ejecta is piled up around the rim. Nothing else has disturbed it, such as another impact or a lava flow. Why do you think there are so few craters on Earth and so many on the Moon?

Reading: “Craters: real and simulated” Is it a simple or complex crater? How old do you think it might be? Why? Why do you think there are so few craters on Earth and so many on the Moon?

Vocab 6.1 page 69 Asteroid: Comet: Complex Crater : Ejecta: Flooded crater: Impact: Meteoroid: Regolith: Simple Crater:

Earth Craters We’ve been modeling craters on the Moon. In reality, impacts happen throughout our solar system and universe on a regular basis. We are going to gather more data about impacts so that we can answer our focus question.

Focus Question 6.2 FQ 6.2 put on page 76 Do not answer yet Will earth experience a major impact in the future? Do not answer yet

3. Crater Recall from you experimentation the two major variables that affect the size of the crater created by an impacting body. Discuss

3. Crater Recall from you experimentation the two major variables that affect the size of the crater created by an impacting body. Size of the meteoroid and its speed at time of impact affect the size of the crater.

3. Crater Recall from you experimentation the two major variables that affect the size of the crater created by an impacting body. Size of the meteoroid and its speed at time of impact affect the size of the crater. Was there a relationship between the speed of the meteoroid (drop height of the marble) and the diameter of the crater?

3. Crater Recall from you experimentation the two major variables that affect the size of the crater created by an impacting body. Size of the meteoroid and its speed at time of impact affect the size of the crater. Was there a relationship between the speed of the meteoroid (drop height of the marble) and the diameter of the crater? The faster the marble traveled, the larger the diameter of the crater.

3. Crater Was there a relationship between the speed of the meteoroid (drop height of the marble) and the diameter of the crater? The faster the marble traveled, the larger the diameter of the crater. Was there a relationship between the size of the meteoroid (mass of the rock) and the diameter of the crater?

3. Crater Was there a relationship between the speed of the meteoroid (drop height of the marble) and the diameter of the crater? The faster the marble traveled, the larger the diameter of the crater. Was there a relationship between the size of the meteoroid (mass of the rock) and the diameter of the crater? The larger the rock, the larger the diameter of the crater.

3. Crater Was there a relationship between the speed of the meteoroid (drop height of the marble) and the diameter of the crater? The faster the marble traveled, the larger the diameter of the crater. Was there a relationship between the size of the meteoroid (mass of the rock) and the diameter of the crater? The larger the rock, the larger the diameter of the crater. The faster or larger the impactor, the larger the crater

4. Moon craters You found out that a crater can result when an object crashes into a surface, and larger, faster objects create larger craters when they hit. Scientists have done experiments using high-powered rifles to demonstrate that high-speed objects produce larger craters when they crash into a surface. The faster the object, the larger the crater. What do you think would happen if something really big and really fast hit the Moon? Something like an asteroid?

4. Moon craters You found out that a crater can result when an object crashes into a surface, and larger, faster objects create larger craters when they hit. Scientists have done experiments using high-powered rifles to demonstrate that high-speed objects produce larger craters when they crash into a surface. The faster the object, the larger the crater. What do you think would happen if something really big and really fast h it the Moon? Something like an asteroid? A large crater—to—object ratio

5. 20:1 ratio Astronomers have come up with an educated approximation of a crater—to- object ratio for large-impact events. The ratio that is generally used for these calculations is 20:1 – a crater with a diameter 20 times larger than the diameter of the meteoroid or asteroid that crashed into the surface. This is only an estimation because there are many factors that affect crater size, including the size of the incoming object, its speed, and the angle of impact. No astronomer has witnessed the impact of an asteroid on a Moon or Earth— size planet, but one thing astronomers do know is that most asteroids travel really fast—between 12, 000 and 20,000 km per second—that’s 6,000 to 10,000 times faster than a bullet!!!

6. Impactor size Notebook sheet 37, Asteroid Size and Impacts, put on page 77 The pages in parentheses are the pages in your book that show images

6. Impactor size Notebook sheet 37, Asteroid Size and Impacts, put on page 77 When we conduct cratering experiments, we know that size of the impact object, and we can measure the size of the crater it produces. In the real world, we can measure the crater, but the size of the object that formed it is a mystery, because it probably vaporized on impact. How can we estimate the size of the object (asteroid) that formed each of these craters?

6. Impactor size The crater-to-object ratio is 20:1. this means that the crater is 20 times greater in diameter than the impactor. So Manicouagan Crater is 20 times larger than the impactor that created it. Manicouagan is 100 km in diameter. The impact object that created the crater is on e-20th the diameter of the Manicouagan Crater. Divide the diameter of the crater into 20 parts to determine the diameter of the impactor. The object that created the Manicouagan Crater was approximately 5 km in diameter. Calculate the size of the asteroids that created the rest of the craters, assuming that scientists’ estimation of a 20:1 crater-to- asteroid ratio is reasonably accurate.

7. Future impacts Talk in your groups to answer the question at the bottom of your sheets. Why are there more craters on the Moon than on Earth? Earth is much larger than the Moon, so you would think that it has been hit more often than the Moon. Be ready to share

7. Future impacts Why are there more craters on the Moon than on Earth? Earth is much larger than the Moon, so you would think that it has been hit more often than the Moon. Evidence of craters on Earth weathers away and erodes due to the forces of wind, water, and tectonics. Earth craters can also be hidden by water or vegetation. Craters don’t weather or hide on the Moon, so they survive for millions of years. Speed and angle may also be a factor

7. Impacts Draw a line of knowledge under you answer and record any new ideas

7. Impacts Draw a line of knowledge under you answer and record any new ideas: Earth is larger than the Moon, so it should be subjected to even more impacts than the Moon. It’s a bigger target. Our atmosphere can only burn up tiny meteoroids; bigger objects still get through. Something must be happening on Earth to erase the evidence of the impacts. Water, wind, and tectonics on Earth weather away and hide craters. Water and vegetation on Earth can hide craters.