Read-and-Interpret-Line-Graphs11111.pptx

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1. Interpreting Graphs

2. Objectives 1. Read and interpret graphs – Extract and analyze information from different types of graphs, focusing on linear graphs. 2. Describe trends in linear graphs – Identify patterns, relationships, and key features such as slope and intercept in linear graphs.

3. Why Graphs Matter? Have you ever used a map or a weather chart? Graphs help us visualize information, making it easier to understand trends, comparisons, and patterns.

4. Introduction Add the labels to the line graph. © Classroom Secrets Limited 2018 title key x axis y axis data

5. Introduction Add the labels to the line graph. © Classroom Secrets Limited 2018 title key x axis y axis data

6. 6 Match the graph to the activity. A car travels at constant speed on the motorway. A car is parked outside a house. A car drives to the end of the road and back. Time Distance from start Time Distance from start Time Distance from start

7. This graph shows the distance travelled by a runner. The graph is a straight line. This means the runner is travelling at a constant speed. The point (100, 240) is on the line. This tells us the runner travels 240 m in 100 s. The speed is   = 2.4 m/s The speed is the gradient of the distance–time graph. If the runner travels d m in t s, the equation of the line is d = 2.4t. You can use the equation of the line to find distances or times. For example: How far does the runner travel in 15 minutes? 15 minutes = 15 × 60 = 900 s When t = 900, then d = 2.4 × 900 = 2160 Distance = 2160 m = 2.16 km.  

8. This graph shows the distance travelled by a runner. The graph is a straight line. This means the runner is travelling at a constant speed. The point (100, 240) is on the line. This tells us the runner travels 240 m in 100 s. The speed is   = 2.4 m/s The speed is the gradient of the distance–time graph. If the runner travels d m in t s, the equation of the line is d = 2.4t. You can use the equation of the line to find distances or times. For example: How long does it take the runner to travel 5 km at this speed? 5 km = 5000 m and so  d  = 5000 d  = 2.4 t  and so 5000 = 2.4 t  and so t= =2083 It takes the runner 2083 s or nearly 35 minutes to travel 5 km.  

9. This graph shows how the temperature of a metal bar changes over 50 minutes. How does the graph show that the rate of cooling is constant? The graph is a straight line so the rate of cooling is constant. Find the gradient of the line. The graph line goes through (0, 500) and (50, 300). The gradient is -4 What does the gradient tell you? The rate of cooling is 4°C/minute.

10. This graph shows how the temperature of a metal bar changes over 50 minutes. The temperature is y °C after t minutes. Find the equation of the line. The y-intercept is 500 so the equation is y = 500 − 4t The bar continues to cool at the same rate. Find the temperature after hours.   hours = 90 minutes and so  t  = 90 and  y  = 500 − 4 × 90 = 140 The temperature after hours is 140 °C.