Lower Secondary Science - Transportation Science - Speed PDF

Lower Secondary Science - Transportation Science - Speed MODULE 2: Transportation Science SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed In this lesson, we are going to discover what is...

Lower Secondary Science - Transportation Science - Speed MODULE 2: Transportation Science SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed In this lesson, we are going to discover what is Transportation Science. In the space below, try to answer the following 3 key questions. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The 3 questions 1. What questions do you have about Transportation Science? 2. What do you want to learn in Transportation Science? 3. What is that ONE word that you can use to summarise this module? SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Transportation Science focuses primarily on fundamental theories, coupled with observational and experimental studies of transportation phenomena and processes, mathematical models, advanced methodologies and novel applications in transportation systems analysis, planning and design. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Essential Questions: Transportation Science What is the cause of motion? How do you describe motion? What are the energy transfers that took place? SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Enduring Understanding: Transportation Science Forces are the cause of motion Motion can be described by distances moved per unit time Energy stores are transferred to kinetic stores during motion SCIENCE DEPARTMENT  Lower Secondary Science - Transportation Science - Speed DISCIPLINE TRANSPORTATION SCIENCE SCIENCE DEPARTMENT TOPIC DIVERSITY / INTERACTIONS / MODELS / SYSTEMS THEME Motion Science of Modes of EU/EQ Describing Causes of Energy Transport Transport Motion Motion Transfers Describing Land UNIT MODELS Motion Air Forces Transfers of Causes of Energy Sea Motion Moments, Sources of Speed Space Density & Energy Energy DIVERSITY Pressure Transfers Talks / INTERACTIONS SYSTEMS Learning Performance LESSON Classroom lessons employing Tasks Journeys Applied Learning and Technologies SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed UNIT 1: Speed SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Knowledge S.I. Units Lengths Time Speed Distance-time graph Speed-time graph SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Cognitive Skills or Practical Skills Cognitive Skills (a) State the associated S.I. units for the 7 base quantities. (b) Understand appropriate units for respective physical quantities (e.g. prefixes and scientific notation). (c) Estimate and measurement of length. (d) Determine time intervals for a certain duration. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Cognitive Skills or Practical Skills (e) Define that speed is the distance travelled in a unit time. (f) Recall and apply the formula “average speed = total distance travelled / total time taken”. (g) Distinguish between average speed and instantaneous speed. (h) Determine the time intervals for distances travelled by moving objects (using stopwatch, video, and Video Motion Analysis software). SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Cognitive Skills or Practical Skills (i) Deduce from the shape of a distance-time graph when a body is: at rest; moving with uniform speed; and moving with non-uniform speed. (j) Deduce from the shape of a speed-time graph when a body is: at rest; moving with uniform speed; and increasing/ decreasing speed at a constant rate. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Cognitive Skills or Practical Skills Practical Skills (k) Measure accurately length and time using appropriate instruments (measuring tape, metre rule, calipers, stopwatch) and their methods. (l) Demonstrate precision and accuracy in making measurements (taking into consideration random and systematic errors such as parallax and errors). SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.1 Physical Quantities and Units A physical quantity is a quantity that can be measured. It consists of a numerical magnitude and a unit. A measurement without appropriate units is meaningless. In 1968, scientists agreed to adopt one universal set of units which is known as the International System of Units (SI units, Système International d'Unités in French). There 2 types of physical quantities, base quantities and derived quantities. There are only 7 base quantities. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The 7 base units SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The 7 base units metre m second s kilogramme kg ampere A θ kelvin K SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Videos Video: Brief History and Introduction to the SI unit: https://www.youtube.com/watch?v=Xpn9eTN ZiCs Are you aware that the kilogram’s definition has been revised recently? https://www.youtube.com/watch?v=Oo0jm1P PRuo SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Derived units derived formula in terms of symbol of SI unit quantities base units area volume speed SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Derived units derived formula in terms of symbol of SI unit quantities base units 2 area metres x metres m volume metres x metres x m3 metres speed metres / second m/s SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 2. Prefixes & Scientific Notation 🖰 Video: http://www.youtube.com/watch?v=0fKBhvDj uy0 SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Prefixes: sub-multiples SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Prefixes: sub-multiples n μµ x 10-6 m x 10-3 0.001 c x 10-2 0.01 d x 10-1 0.1 SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Prefixes: multiples X SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Prefixes: multiples k X 103 M x 106 9 G x 10 SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Conversion 1 cm =............................... mm 1m =............................... cm 1 km =............................... m 75 m = ………………………….… mm 0.36 kg = ……………………….…… g 2.4 h = ………………………….… s SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Conversion 1 cm = 10............................... mm 1m = 100............................... cm 1 km = 1000............................... m 75 m = 75 000 ………………………….… mm 0.36 kg 360 = ………………………….… g 2.4 h = 8 640 ………………………….… s SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.3 Estimations SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.3 Estimations 8800 m 6400 km 10-15 m SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Estimate the following physical quantities: Physical Quantity Length Length of a classroom desk Height of a classroom Thickness of a coin Thickness of a strand of hair SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Estimate the following physical quantities: Physical Quantity Length Length of a classroom desk 0.5 metres Height of a classroom 3 metres Thickness of a coin 2 millimetres Thickness of a strand of hair 0.1 millimetres SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.4 Measurement of Time S.I. unit: second, [ ] Other units:........................................... Instrument used:................................................... Human reaction time is the time interval between seeing an event and starting or stopping the stopwatch. Human reaction time is about 0.20 s. This introduces a total error of about 0.40 s. In order to reduce the error due to human reaction time, one way is to take multiple readings (n) and take the average. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.4 Measurement of Time S.I. unit: second, [ s ] hours(h) , minutes (min) Other units:........................................... digital stop watch Instrument used:................................................... Human reaction time is the time interval between seeing an event and starting or stopping the stopwatch. Human reaction time is about 0.20 s. This introduces a total error of about 0.40 s. In order to reduce the error due to human reaction time, one way is to take multiple readings (n) and take the average. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.5 Measurement of Length Length is the distance between two points. SI unit: metre [ ] Other units: …................................................... Different instruments have different uses, depending on the precision of instrument required. The precision of instrument is the smallest unit an instrument can measure. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.5 Measurement of Length Length is the distance between two points. SI unit: metre [ m ] Inch, foot, mile Other units: …................................................... Different instruments have different uses, depending on the precision of instrument required. The precision of instrument is the smallest unit an instrument can measure. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Measuring instruments SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Parallax error Parallax error is due to wrong positioning of eye during measurement. Parallax error will give rise to inaccurate readings. It can be avoided by: ∙ Placing the rule or tape on its edge against the object to be measured. ∙ Take the reading from a position directly above the point (i.e. not at an angle). SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Measuring lengths using Digital Vernier Calipers Digital Vernier Calipers are often used to measure short lengths and diameters of small objects. They display the length as a numeric value on their digital display. We can use the digital vernier calipers to measure: – External diameter of a container – Internal diameter of a container – Depth of a test tube or hole The digital vernier caliper is used to measure lengths of up to 100.0 or 150.0 mm. Precision of instrument (or least count): 0.1 mm/0.01 cm or 0.01 mm/0.001 cm SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The parts of the digital vernier caliper are indicated in the diagram below: Watch the video on how to use a pair of Digital Vernier calipers: https://www.youtube.com/watch?v=EALJV0ob-U0 SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.6 Measurement No measurement is ever perfectly accurate. There is a difference between Accuracy and Precision. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Accuracy v.s. Precision Precision is independent of accuracy. You can be very precise but inaccurate. You can also be accurate but imprecise. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Random v.s. Systematic errors SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.7 Speed Speed is defined as the rate of change of distance with respect to time, or ……………………………………………………… ………………………… The S.I. unit of speed is …………………………..………... SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.7 Speed Speed is defined as the rate of change of distance with respect to time, or The distance travelled per unit time. The S.I. unit of speed is ……………… m/s …..………... SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Average speed and Instantaneous speed Average speed of an object is is the total distance travelled divided by the total time taken. Instantaneous speed of an object is is the speed at a particular instant. Equation: Average speed = Total Distance / Total Time SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Average speed and Instantaneous speed Average speed of an object is the total distance travelled divided by the total time taken. Instantaneous speed of an object is the speed at a particular instant. Equation: Average speed = Total Distance / Total Time SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.8 Measurement of speed 1.8.1 Simple stopwatch and distance method Traditionally, the speed of an object can be measured by using a tape and a stopwatch. During school sports day, athletes will run a fixed distance and the time taken will be measured by using a stopwatch. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed starter starting pistol timekeeper 100 m A B finishing line Fig. 2.1 (not drawn to scale) However, this method only allows us to measure the average speed, as we could only measure the time taken for a distance (of 100 meters) travelled. We cannot measure the speed at different times of the race. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.8.2 Speedometer With the advances in technology, the speed of an object can be measured using a speedometer. The speed of the car can be measured by a speedometer as shown below: SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The speedometer measures the instantaneous speed in terms of km/h. For a typical car, the speedometer displays a range of 0 to 200 km/h. Do you know how to convert km/h to m/s? Show your working below. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed The speedometer measures the instantaneous speed in terms of km/h. For a typical car, the speedometer displays a range of 0 to 200 km/h. Do you know how to convert km/h to m/s? Show your working below. 1 km/hr = 1000 m / (60 x 60 s) = (1000/3600) m/s = 1/3.6 m/s = 0.278 m/s Hence 1 m/s = 3.6 km/h SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.8.3 Video Motion Analysis Video motion analysis is a technique used to get information about moving objects from video. Examples of this include gait analysis, sport replays, speed and acceleration calculations and, in the case of team or individual sports, task performance analysis. The motion analysis technique usually involves a high-speed camera and a computer that has software allowing frame-by-frame playback of the video. Traditionally, video motion analysis has been used in scientific circles for calculation of speeds of projectiles, or in sport for improving play of athletes. Recently, computer technology has allowed other applications of video motion analysis to surface including things like teaching fundamental laws of physics to school students, or general educational projects in sport and science. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.9. Describing Motion using a Distance-Time Graph An odometer is an instrument used for measuring the distance travelled by a vehicle, such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two (electromechanical). If the data from an odometer is exported into a graph, it is known as an odometer graph. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 1 A simple odograph is shown in the graph below SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Deduce from the shape of a distance-time graph when a body is: (i) at rest: ………….. (ii) moving with uniform speed: ………….. (iii) moving with non-uniform speed: ………….. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Deduce from the shape of a distance-time graph when a body is: (i) at rest: C (ii) moving with uniform speed: A (iii) moving with non-uniform speed: B SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 AB: BC: CD: SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 AB: From 0 to 5 s, the car is moving at a constant speed of 20/5 = 4 m/s. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 BC: From 5 to 15 s, the car is not moving. Speed = 0 m/s. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 CD: From 15 to 25 s, the car is moving at a constant speed of = (40-20)/(25-15) = 20/10 = 2.0 m/s. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 (b) Calculate the average speed of the car for whole journey. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 2 (b) Calculate the average speed of the car for whole journey. Average speed = Total distance / total time = 40 m/25 s = 1.6 m/s SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 3 Four objects are moving along a straight line. The distance of an object from a fixed point on the line is plotted against time for each object. SCIENCE DEPARTMENT  Lower Secondary Science - Transportation Science - Speed Example 3 Which of the object is moving: (i) with increasing speed: ……..… (ii) with decreasing speed: …….… (iii) with constant speed: …….… (iv) backwards: …….. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 3 Which of the object is moving: (i) with increasing speed: B (ii) with decreasing speed: C (iii) with constant speed: A/D (iv) backwards: D SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.10 Describing motion using a Speed-Time Graph A speedometer or speed-meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the early 20th century, and as standard equipment from about 1910 onwards. Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an airspeed indicator. When the data from the speedometer is downloaded, it is known as a speedometer graph. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.10 Describing motion using a Speed-Time Graph The speed-time graph below illustrates how the speed of an object changes with time. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed 1.10 Describing motion using a Speed-Time Graph The motion of any moving object can be described by its speed–time graph. A horizontal line indicates a constant or uniform speed. If the line slopes upward from left to right, the object is speeding up. If the line slopes downward from left to right, the object is slowing down. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 4 A simple speedograph is shown in the graph below. Notice how the shape of graph is the same as example 1 but labelled with different axis? SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 4 Deduce from the shape of a speed-time graph when a body is: (i) at rest: ……..… (ii) moving with uniform speed: …..…… (iii) moving with increasing speed: ……..… (iv) moving with decreasing speed: ……..…. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 4 Deduce from the shape of a speed-time graph when a body is: (i) at rest: 0,0 (origin) and end (ii) moving with uniform speed: C (iii) moving with increasing speed: A, B (iv) moving with decreasing speed: D SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 5 (a) Describe the motion of the car. AB: ……………………………………………….. BC: ……………………………………………… SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 5 (a) Describe the motion of the car. AB: From t=0 to 2 s, Speed increases from 0 to 5 m/s at a constant rate. BC: From t=2 to 6 s, Speed is constant at 5 m/s. CD: From t=6 to 10 s, Speed decreases from 5 to 0 m/s at a constant rate. SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 5 (b) State the instantaneous speed of the car at the following times. Time t = 1 s: …………………………………… Time t = 4 s: …………………………………… SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Example 5 (b) State the instantaneous speed of the car at the following times. 2.5 m/s Time t = 1 s: …………………………………… 5.0 m/s Time t = 4 s: …………………………………… SCIENCE DEPARTMENT Lower Secondary Science - Transportation Science - Speed Thanks THE END SCIENCE DEPARTMENT