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Science Starter

Science Starter. How would you describe motion? * Do Not use the terms move, moving or movement in your answer!. Science Starter. The speed of an animal is how fast it is moving . A speed of 6 m/s (meters per second) means that the animal moves a distance of 6 meters every second.

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Science Starter

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  1. Science Starter • How would you describe motion? *Do Not use the terms move, moving or movement in your answer!

  2. Science Starter The speed of an animal is how fast it is moving. A speed of 6 m/s (meters per second) means that the animal moves a distance of 6 meters every second. • How would you measure the speed of an animal? • What do you think are the fastest animals?

  3. Motion

  4. Introductory Video • Physical Science: Motion • http://player.discoveryeducation.com/index.cfm?guidAssetId=1cedd218-43c5-42ee-9864-55406e427dc1

  5. Motion • Motion: a change in position in a certain amount of time

  6. Speed • Speed: the rate at which an object moves • Anything that is changing its position has speed • Example: ocean currents, the moon, a car, a person walking

  7. Speed • Formula: speed = distancetime • Constant Speed: speed that does not change • This is shown a straight diagonal line on a distance-time graph • Average Speed: dividing the total distance by the total time

  8. Measuring Motion Sample problem: At what speed did a plane fly if it traveled 1760 meters in 8 seconds? Step 1 – Write the formula. Speed = Distance/Time Step 2 – Substitute given numbers and units. Speed = 1760 meters/8 seconds Step 3 – Solve for the unknown. Speed = 220 meters/second (m/sec)

  9. Measuring Motion Practice Problems: • A car travels 240 kilometers in 3 hours. What is the speed of the car during that time? • The speed of a cruise ship is 50 km/hr. How far will the ship travel in 14 hours?

  10. A car travels 240 kilometers in 3 hours. What is the speed of the car during that time? Step 1: Speed = Distance/Time Step 2: Speed = 240 km/3hrs Step 3: Speed = 80 km/hr Answer: The speed of the car is 80 km/hr.

  11. The speed of a cruise ship is 50 km/hr. How far will the ship travel in 14 hours? Step 1: Speed = Distance/Time Step 2: Speed = 50km/hr Step 3: 50 km x 14 hrs = 700km/14 hrs Answer: The ship will travel 700 km in 14 hrs.

  12. Measuring Motion • The speed of a moving object is not always constant. • For example, a cyclist takes a long bike ride. She begins slowly for the first two hours and picks up speed for the third hour. After three hours, she takes a break before finishing the final two hours of her ride.

  13. Measuring Motion • Clearly, her speed changes many times throughout her journey. • Dividing the total distance by the total time does not tell you her speed for every point of her journey. • Instead it gives you her average speed. • In fact, the formula you just learned for calculating speed – distance/time – always gives you the average speed.

  14. Velocity • Velocity: speed in a given direction • Example: Suppose a runner moves eastward at 10 m/sec • His speed is 10 m/sec • His velocity is 10 m/sec east

  15. Velocity Combining Velocities Suppose you are rowing a boat downstream at 16 km/hr. Would it surprise you to learn that you are actually going faster than 16 km/hr? How is this possible?

  16. Measuring Motion The river is also moving, say at 10 km/hr. Since you are rowing downstream, you are going in the same direction as the river. The two velocities combine. So you are moving at 26 km/hr. *Velocities that have the same direction are added together.

  17. Measuring Motion If you were rowing 16 km/hr upstream, you would be going 16 km/hr – 10 km/hr, or 6 km/hr. * Velocities that have opposite directions are subtracted from each other.

  18. Frame of Reference • Frame of Reference: the background or point that is assumed to be stationary and is used for comparison when motion is described • Depends on the type of movement and the position which you are observing from • Most common frame of reference: the Earth

  19. Frame of Reference • http://www.classzone.com/books/ml_science_share/vis_sim/mfm05_pg7_relmotion/mfm05_pg7_relmotion.html

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