Lesson 5 — Discuss worksheet – Start 4.2

• Natuurkunde / Scheikunde
• Middelbare school
• havo, vwo
• Leerjaar 2

This lesson

•  Recap
• Discussing the worksheet
• Start §4.2 — Taking accurate measurements
•  Working independently

Learning goals

•  Check the worksheet
• Explain the difference between accuracy and precision
• Define significant figures
•  Define reaction time
•  Know how to measures time precisely

Recap?

Formula for speed

Speed=​time​​distance​​

v=​t​​d​​

v: velocity

d: distance

t: time

Rearranging the formula for speed

v=​t​​d​​

3=​2​​6​​

Rearranging the formula for speed

v=​t​​d​​

Speed: 

Distance:

d=v⋅t

Time:

t=​v​​d​​

Converting 

km/h <-> m/s 

Discussing 

the worksheet

Discussing 

the worksheet

1. Compare your answers with your neighbour.
2.  One of you gets an answer sheet, check your answers with the answers sheet.
3. Done —> Read: 4.2, do: Yellow block exercises + workbook exercises.

4.2 Taking accurate measurements

Key concepts

•  Precision
• Accuracy
• Significant figures
•  Reaction time
• Timing gates

Exercise

Define these concepts by discussing them with your neighbour

• Precision
  
• Accuracy
  
• Significant figures
  

Use the book to figure out what they mean

 Precision and accuracy?

Precision and accuracy

Accuracy: How close the measurement is to the actual value.

Precision: How refined the measurement is, shown in the number of significant numbers.

Usain bolt

Time:

Yohan Blake

Time:

Justin Gatlin

Time:

2012 olympics — 100 m sprint

Usain bolt

Time: 10 s

Yohan Blake

Time: 10 s

Justin Gatlin

Time: 10 s

Their 2012 times

1 significant number

Usain bolt

Time: 9.6 s

Yohan Blake

Time: 9.8 s

Justin Gatlin

Time: 9.8 s

Their 2012 times

2 significant number

Usain bolt

Time: 9.63 s

Yohan Blake

Time: 9.75 s

Justin Gatlin

Time: 9.79 s

Their 2012 times

3 significant number

Precision and accuracy

Accuracy: How close the measurement is to the actual value.

Precision: How refined the measurement is, shown in the number of significant numbers.

Significant figures: The amount of digits in a measurment.

Homework

Read: 4.2

Do: 4.2 yellow block exercises

Learning goals

•  Check the worksheet
• Explain the difference between accuracy and precision
• Define significant figures
•  Define reaction time
•  Know how to measures time precisely