10S1 Lesson 5/6 - Measurement/Experimental design

• Chemistry
• Secondary Education

Lesson 1 - What is IGCSE Chemistry?

<ol><li>Name appropriate apparatus for the measurement of time, temperature, mass and volume, including (a) stopwatches,(b) thermometers, (c) balances, (d) burettes, (e) volumetric pipettes, (f) measuring cylinders, (g) gas syringes</li><li>Suggest advantages and disadvantages of experimental methods and apparatus</li></ol>

Daily Review

• (a) Identify the number of significant figures in each measurement.
• (b) Name the apparatus or
• (c) Write the measurement reading.

The clock's ticking!

How many significant digits are there in this measurement:  0.0507 dm3  ?

How many significant digits are there in this measurement:  0.0000005 dm3  ?

How many significant digits are there in this measurement: 2400 min ?

How many significant digits are there in this measurement:  9.776 g ?

How many significant digits are there in this measurement:  20008 cm3 ?

Name this apparatus.

Name these apparatuses.

What is the reading on the burette?

What is the reading on the burette?

What is the reading on the measuring cylinder?

What is the reading on the measuring cylinder?

What is the reading on the thermometer?

What is the reading on the stopwatch in s?

Volumetric pipette or graduated pipette

10.0 cm³

25.0 cm³

Burette 

(variable volumes)

50.0 cm³

Measuring cylinder

Usually used in titrations

Volumetric pipette or graduated pipette

10.0 cm³

25.0 cm³

Burette 

(variable volumes)

50.0 cm³

Measuring cylinder

Usually used in titrations

Uncertainty

• All measurements involve uncertainty.
• All measurement's last digit is always an estimate.
• The digits that you record when you measure something are called significant digits.

Ruler A:   4.2 cm or 4.3 cm?

Ruler B:   4.27 cm or 4.28 cm?

Accuracy up to 1 cm

Accuracy up to 0.1 cm

Lesson 1 - What is IGCSE Chemistry?

Daily Review

• Arrange the correct order of the steps using the scientific method.
• Share or give your feedback.

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Daily Review

• Arrange the correct order of the steps using the scientific method.
• Share or give your feedback.

Designing an Investigation

• Identify the independent variable and the values you plan to use for it
• Identify the dependent variable and the method to be used to measure it
• Suggest how you will control variables
• Suggest the most appropriate apparatus and techniques
• Outline the experimental procedure in a series of numbered steps
• Identify risks and describe any safety precautions
• Record and analyse the results or data
• Trials or repeat readings and sources of error
• Make your conclusion
• Share your findings with others

Experimental design

• Read the essential points of a good experimental design.
• Highlight the sentence or line in the sample investigation of the points you can find.
• Answer the given questions.
• Create a slide presentation containing the explanation for your answers.

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Designing an Investigation

• Identify the independent variable and the values you plan to use for it
• Identify the dependent variable and the method to be used to measure it
• Suggest how you will control variables
• Suggest the most appropriate apparatus and techniques
• Outline the experimental procedure in a series of numbered steps
• Identify risks and describe any safety precautions
• Record and analyse the results or data
• Trials or repeat readings and sources of error
• Make your conclusion
• Share your findings with others

1

Lesson 1 - What is IGCSE Chemistry?

2

Summary

• Read measurements using apparatuses
• Wrote and recorded measurements properly
• Reviewed the SI quantities and units
• Did unit conversions
• How to know the certain and uncertain digits in a measurement
• Identified the number of significant digits in the recorded measurements