Science 3rd quarter

• Observation is the process of using the five senses to gain information
• Two kinds of observation:

  • Qualitative: describes using words (e.g., red apples, young and beautiful)
  • Quantitative: describes using numbers or measurement (e.g., 5 pieces of apple, 13 years old)
• In qualitative observation, you describe the picture using words
• In quantitative observation, you describe the picture using numbers or measurements
• Two kinds of quantitative observation:

  • Scalar: have only magnitude (number) and a unit but don’t have direction (e.g., 75 kg, 5 feet)
  • Vector: have both magnitude (number) and a direction (e.g., 10 km North, 2 steps forward)
• Identifying whether observations are scalar or vector:

  • Has magnitude and direction: Vector
  • Has magnitude only: Scalar
  • Examples:
  • 12 kg: Scalar
  • 10 meters, North: Vector
  • 100 km, East: Scalar
  • 100 km: Vector
  • 8 years old: Scalar
• Motion is the continuous change of position with respect to a fixed/reference point
• Distance:

  • A scalar quantity
  • The length of a path between two points
  • Symbol: d
  • How to solve: Just add all the distance travelled
• Calculating distance:

  • 15 meters + 4 meters = 19 meters
  • 12 meters + 6 meters = 30 meters
  • A car ran 20 km west, then 15 km north, and another 60 km east. Total distance: 95 km
• Displacement:

  • A vector quantity
  • Has direction and magnitude
  • Shortest distance from the starting point to the ending point
  • Symbol: ∆d
• Calculating displacement:

  • 12 meters, West
  • 6 meters, North
  • Thirdy runs 20 meters east then 14 meters west. Total distance: 34 meters, Displacement: 6 meters, East
  • A student walked 8 meters east then back home. Distance: 16 meters, Displacement: 0 meter
  • Xandree moves arms up and down 5 times. Distance: 0, Displacement: 0
  • Elijah runs 30 feet north, 30 feet west, and 30 feet south. Total distance: 90 feet, Displacement: 30 ft, West
• Drawing and finding distance and displacement in various scenarios
• Quantitative Observation:

  • Scalar: has only magnitude (number) and a unit but doesn’t have direction (e.g., 75 kg, 5 feet)
  • Vector: has both magnitude (number) and a direction (e.g., 10 km North)
• Distance:

  • Scalar quantity, the length of a path between two points (symbol: d)

  Displacement:

  • Vector quantity, the shortest distance from the starting point to the ending point (symbol: ∆d)
• In the context of single-celled organisms, substances can easily enter the cell due to a short distance, while in multicellular organisms, the distance is larger due to a higher surface area to volume ratio
• Speed and Velocity:

  Speed:

  • Scalar quantity that refers to how fast an object is
  • Defined as distance travelled divided by the time of travel
  • Types of speed: Average Speed, Instantaneous Speed, Constant Speed
• Average Speed:

  • Speed over the whole journey

  Instantaneous Speed:

  • Speed at any instant or at a specific point in time

  Constant Speed:

  • Not changing speed, same amount of speed from the beginning to end
• Velocity:

  • Vector quantity that refers to the rate at which an object changes its position
  • The speed of an object in a particular direction
• Average Velocity:

  • Equal to overall displacement per total time of travel

  Instantaneous Velocity:

  • The velocity at any instant

  Constant Velocity:

  • Not changing speed, same amount of speed from beginning to last
• In the context of speed and velocity, speed is a scalar quantity, while velocity is a vector quantity
• Activity:

  1. What is the average speed of a person running 100 m in 30 s?

  2. If a car moves with an average speed of 50 km/h, how far would it travel in 5 h?

  3. A girl cycles for 3 hrs at a speed of 40 km/h. What distance did she travel?

  4. A car travelled 540 km in 6 hours. What speed did it travel at?

  5. Jim travelled at a speed of 46 meters/min for 12 minutes. What was the distance covered?
• Activity:

  1. A jeepney drives along a straight highway for 16 minutes with a displacement of 1600 m south. What is the jeep’s velocity?

  2. Philip walks along a straight path from his house to his school. How long will it take him to get to school if he walks 500 m west with an average velocity of 5 m/s west?

  3. What is the velocity of a plane that travelled 1,575 miles northeast from Tarlac to Seoul, Korea in four hours?

  4. A car travels North at 100 km/hr. How many hours will it take to cover a distance of 750 km?

  5. How far did a biker travel if he spent 4 hours cycling with a speed of 30 km/hr heading east?
• Quantitative Observation:

  • Scalar: has only magnitude (number) and a unit but doesn't have direction (e.g., 75 kg, 5 feet, 1 minute, 15 years old)
  • Vector: has both magnitude (number) and a direction (e.g., 10 km North, 2 steps forward, 5 m down)
• Speed:

  • Scalar quantity
  • Refers to how fast/slow an object is
• Velocity:

  • Vector quantity
  • Refers to the rate at which an object changes its position
• Acceleration:

  • A vector quantity
  • Rate of change in velocity of an object
  • Acceleration can be an increase in speed/velocity or a decrease (deceleration)
• Acceleration happens when:

  a. Change in Speed (e.g., a cyclist going from 60 km/hr to 40 km/hr)

  b. Change in Direction (e.g., a person walking 5 m/s north then 5 m/s east)

  c. Change in Speed and Direction (e.g., a person walking 5 m/s north then 10 m/s east)
• Acceleration Formula:

  A = (Final velocity - Initial velocity) / time
• Acceleration Calculation Examples:

  1. Car accelerates from rest at 24 m/s west in 6 seconds. Find its average acceleration.

  2. Lizard accelerates from 2 m/s to 10 m/s in 4 seconds. Calculate the average acceleration.

  3. Ball rolled at 30 m/s and stops after 6 seconds. Determine if it accelerated or decelerated and find its acceleration.
• Seatwork:

  • Copy and complete the table by solving missing values of quantities
• Solving Questions:

  • Car accelerates from 50 mph to 80 mph in 5 seconds. Calculate the acceleration.
  • Space telescope goes from stationary to 1700 m/s in 25 seconds. Find the acceleration.
  • Ball rolled at 12 m/s and stops after 36 seconds. Calculate its acceleration.
• Activity:

  1. Helicopter's speed increases from 25 m/s to 60 m/s in 5 seconds. Find its acceleration.

  2. Cyclist slows down from 25 mi/hr to 6 mi/hr in 10 seconds. Calculate the deceleration.

  3. Car starts from a stoplight and travels at 10 m/s east in 20 seconds. Determine the acceleration.

  4. Mario runs at 5 m/s and finishes at the same speed in 1 minute. Find Mario's acceleration.
• Wave


  The source of all waves produced by a repeated motion
• Mechanical Wave requires a medium for waves to propagate or to be produced
• Students repeated the motion multiple times
• Summary of types of waves

  Transverse Waves - particles move perpendicular, Longitudinal Waves - particles move parallel, Surface Waves - particles undergo circular motion
• Transverse Waves have particles of the medium move perpendicular to the direction where the wave moves
• A travelling disturbance that carries energy from one place to another location with or without a medium
• Examples of waves

  1. Waving their hands

  2. Doing a body wave

  3. Doing a group wave using their arms connected to each other
• Activity: Write transverse, longitudinal, or surface by its relation to the given word