Here are the steps to improve the accuracy and precision of measurements:
1. Calibrate equipment regularly using standard samples of known mass/volume. This reduces systematic error.
2. Use appropriate precision tools - e.g. measuring cylinders for liquids, not beakers. This reduces random error.
3. Take multiple measurements and report the average. This reduces the effect of random error.
4. Record measurements to an appropriate number of significant figures based on the precision of the tool. This communicates the level of uncertainty.
5. Consider and report possible sources of error, both systematic and random. This provides full context for the results.
Following these steps helps produce measurements that are both accurate to
This presentation discusses in detail about the procedure involved in two-factor MANOVA. Both the analysis i.e. multivariate as well as univariate has been shown in this design by solving an illustration using SPSS software.
A tutorial on LDA that first builds on the intuition of the algorithm followed by a numerical example that is solved using MATLAB. This presentation is an audio-slide, which becomes self-explanatory if downloaded and viewed in slideshow mode.
This presentation discusses the application of discriminant analysis in sports research. One can understand the steps involved in the analysis and testing its assumptions.
This presentation discusses the procedure involved in two-way mixed ANOVA design. The procedure has been discussed by solving a problem using SPSS functionality.
This presentation discusses in detail about the procedure involved in two-factor MANOVA. Both the analysis i.e. multivariate as well as univariate has been shown in this design by solving an illustration using SPSS software.
A tutorial on LDA that first builds on the intuition of the algorithm followed by a numerical example that is solved using MATLAB. This presentation is an audio-slide, which becomes self-explanatory if downloaded and viewed in slideshow mode.
This presentation discusses the application of discriminant analysis in sports research. One can understand the steps involved in the analysis and testing its assumptions.
This presentation discusses the procedure involved in two-way mixed ANOVA design. The procedure has been discussed by solving a problem using SPSS functionality.
Introduces and explains the use of multiple linear regression, a multivariate correlational statistical technique. For more info, see the lecture page at http://goo.gl/CeBsv. See also the slides for the MLR II lecture http://www.slideshare.net/jtneill/multiple-linear-regression-ii
Quantitative Analysis for Emperical ResearchAmit Kamble
Overview for Approach Methods for quantitative analysis; which includes
1) Planning of Experiments
2) Data Generation
3) presentation of report
some numerical approach methods; data modeling; hypothesis methods
How International Is Our School? MA DissertationStephen Taylor
Title: A pilot-test of a visualization and set of evaluation rubrics for factors affecting the promotion of international-mindedness and global engagement (IMaGE) of a school.
In this formative in-class Criterion C task, we connect the content from the last unit with some basics on Forces, using the Red Bull Stratos jump as a basis.
Introduces and explains the use of multiple linear regression, a multivariate correlational statistical technique. For more info, see the lecture page at http://goo.gl/CeBsv. See also the slides for the MLR II lecture http://www.slideshare.net/jtneill/multiple-linear-regression-ii
Quantitative Analysis for Emperical ResearchAmit Kamble
Overview for Approach Methods for quantitative analysis; which includes
1) Planning of Experiments
2) Data Generation
3) presentation of report
some numerical approach methods; data modeling; hypothesis methods
How International Is Our School? MA DissertationStephen Taylor
Title: A pilot-test of a visualization and set of evaluation rubrics for factors affecting the promotion of international-mindedness and global engagement (IMaGE) of a school.
In this formative in-class Criterion C task, we connect the content from the last unit with some basics on Forces, using the Red Bull Stratos jump as a basis.
Defining Inquiry for the PreK-12 continuum. Inquiry as a 'theory of everything' of good education, built on a solid foundation of well-taught knowledge, skills and concepts.
Assessment Assignment: Bath MA International EducationStephen Taylor
This is an assignment I completed for the Assessment unit of the University of Bath's MA in International Education programme.
It is shared here to allow me to embed it onto my professional reflective blog at http://ibiologystephen.wordpress.com
Downloads have been disabled.
This was made with Jon Schatzky and Barney Trezona.
As a task in our MYP Areas of Interaction workshop, we worked together to unpack on AOI for students. We chose Approaches to Learning, and then focused on 'Social'. Using the document "Making the PYP Happen' and its trans-disciplinary skills, we then decided to create a rubric for the skill of 'Conflict Resolution'.
I use this lab sequence over a couple of lessons to get to grips with some basics of different types of reactions, balancing, writing formulas and problem-solving.
This is an assignment for my University of Bath MA in International Education, based on the tensions in transition from MYP to DP. It revolved around the different schools of through about learning and, most importantly, inquiry. It focuses on the different approaches to inquiry characterised by Dewey and Vygotsky, before moving onto a modern look at evidence-based practices.
MA International Education University of Bath assignment (Education in and International Context).
In this assignment I have tried to propose an original idea for helping schools define and measure the degree to which they demonstrate the values of international education.
This is heavily adapted from the resource posted by Ellen Mayo to the Access Excellence website (http://www.accessexcellence.org/AE/AEC/AEF/1995/mayo_dna.php). It has been edited to fit on one single side of A3, to expedite the cutting-sticking process for students and to more directly address IB Biology assessment statements.
Please visit the original resource link for full explanation and instructions:
http://www.accessexcellence.org/AE/AEC/AEF/1995/mayo_dna.php
Michael HricikENG 162This assignment will be about 2-3 double-sp.docxARIV4
Michael Hricik
ENG 162
This assignment will be about 2-3 double-spaced
typed pages
Customer Service Evaluation
I am going to have you evaluate customer service at your current place of employment, or you can focus on a previous place of employment. You are looking at the service mainly as an employee, though you can also look at the service as a student or customer as well. You can focus a specific department or area at your place of employment, or you can look at the company/institution as a whole. For instance, I have worked at WCCC for twenty years. One area of the college that I feel is especially effective is the Continuing Education Division. I have taken about eight classes, my children have taken numerous classes, and so has my wife. I also have had quite a few past and current students take non-credit classes. I am looking at this as both an employee and as a customer. The overall variety of classes offered is quite varied. The instructors are usually excellent (I took an Intro to Acting course, and I really enjoyed it). The courses are usually offered at convenient times and places. Moreover, the staff in the Continuing Education Division is accessible and informed.
Conversely, I previously worked at department store in Greensburg called Joseph Horne’s. Compared to Kaufmann’s, it was lacking in several areas. It had old-fashioned cash registers, which were not always accurate. At times, the merchandise selection was lacking and changed little from season to season. In addition, the prices seemed to be too high, though there were sales at times. It did have quite a few loyal customers, but it was no longer able to compete with other similar stores.
So, as I have stated above, you can choose one area or department where you work, or have currently work. On the other hand, you can focus on the organization as a whole. What I would like you to do is evaluate a total of four different points of criteria. Some common areas are: response to customer needs, level of organization, the effectiveness of the management of the department or area, the knowledge of the employees, the ability to solve problems, the level of resources of the department, the teamwork of employees, etc.
As an insider, I would like you to rate how well the area, department, or the organization does.
This is what you will need to do:
1. Use an effective title to express your “attitude” or opinion. Something like UPS Isn’t Always on Time or
The Olive Garden is Cooking
2. In your introduction, indicate the name of the place or organization that you intend to evaluate. You can state how long you have worked there, or how long you had been there. Indicate the position or position that you held. State the department, area, or name of the organization that you intend to evaluate. Finally, state your overall opinion or thoughts on the organization as a whole. Keep in mind that you can rate certain points very highly, and you can rate ...
Lab 1 Measurement Accuracy and Precision Lab Materi.docxsmile790243
Lab 1: Measurement: Accuracy and Precision
Lab Materials:
Rulers
Non-programmable calculator
1 Sheet of notebook paper
Scissors
Stopwatch
Kitchen Balance (measures to nearest 1g)
Plastic cups
Measuring spoons
Water
2
Name: ___________________________ Date: _____________
Measurement: Accuracy and Precision
When scientists collect data, they must determine the accuracy and precision of their measurements.
Accuracy refers to how close the measured quantities are to the actual or true value. Precision refers to
the closeness of each of the data sets to one another. To distinguish between these two terms, it is
useful to think of a target and the position of the measurements on the target. If the measurements are
clustered together but away from the center of the target, then we would say the measurements are
precise, but not accurate. If the data hits the center on the target, the measurements are precise and
very accurate, i.e. the values collected are close to the true value one should obtain. In today’s lab,
you will make measurements and perform calculations to the appropriate number of significant figures.
You will then determine if your measurements are precise and/or accurate. Before doing this though,
you will have several exercises that test your knowledge of significant figures.
Significant Figures
In any given measurement, non-place holding digits are referred to as significant digits or most often
“sig figs” (for significant figures). The greater the number of sig figs, the greater the precision in the
measurement. To determine the number of significant figures in a given quantity, follow these rules:
1. All nonzero numbers are significant.
2. Zeroes located between two numbers are significant.
3. Zeroes located after a decimal point are significant
4. Zeroes located to the left of the first nonzero number are NOT significant; therefore, the
number 0.002 has only 1 significant figure since the 3 zeroes prior to the number 2 are
serving only as place holders.
5. Zeroes located at the end of a number but before a decimal point are ambiguous. For
instance, we cannot determine the number of sig figs in say, 6350. To avoid this
confusion, we either write 6350. or 6.350 x 103 to indicate that the zero is significant.
6. Exact numbers (numbers obtained from counting or numbers originating from defined
quantities, such as 12 inches = 1 foot) have infinite number of significant digits.
1. For the following examples, determine the number of significant figures.
a. 4762 __________
b. 902 __________
c. 0.0000438 __________
d. 987,000,000,000 __________
e. 0.000834 __________
3
f. 4.32 x 10
4
__________
g. 9.2735 x 10
-5
__________
h. 6,049,071 __________
i. 678.20 __________
j. 903,089,932,000. __________
Significant Figures in Calculations
One important concep ...
measurement and scaling is an important tool of research. by following the right and suitable scale will provide an appropriate result of research.this slide show will additionally provide the statistical testing for research measurement and scale.
Data Science Interview Questions | Data Science Interview Questions And Answe...Simplilearn
This video on Data science interview questions will take you through some of the most popular questions that you face in your Data science interviews. It’s simply impossible to ignore the importance of data and our capacity to analyze, consolidate, and contextualize it. Data scientists are relied upon to fill this need, but there is a serious dearth of qualified candidates worldwide. If you’re moving down the path to be a data scientist, you need to be prepared to impress prospective employers with your knowledge. In addition to explaining why data science is so important, you’ll need to show that you're technically proficient with Big Data concepts, frameworks, and applications. So, here we discuss the list of most popular questions you can expect in an interview and how to frame your answers.
Why learn Data Science?
Data Scientists are being deployed in all kinds of industries, creating a huge demand for skilled professionals. The data scientist is the pinnacle rank in an analytics organization. Glassdoor has ranked data scientist first in the 25 Best Jobs for 2016, and good data scientists are scarce and in great demand. As a data, you will be required to understand the business problem, design the analysis, collect and format the required data, apply algorithms or techniques using the correct tools, and finally make recommendations backed by data.
You can gain in-depth knowledge of Data Science by taking our Data Science with python certification training course. With Simplilearn’s Data Science certification training course, you will prepare for a career as a Data Scientist as you master all the concepts and techniques. Those who complete the course will be able to:
1. Gain an in-depth understanding of data science processes, data wrangling, data exploration, data visualization, hypothesis building, and testing. You will also learn the basics of statistics.
Install the required Python environment and other auxiliary tools and libraries
2. Understand the essential concepts of Python programming such as data types, tuples, lists, dicts, basic operators and functions
3. Perform high-level mathematical computing using the NumPy package and its large library of mathematical functions
Perform scientific and technical computing using the SciPy package and its sub-packages such as Integrate, Optimize, Statistics, IO and Weave
4. Perform data analysis and manipulation using data structures and tools provided in the Pandas package
5. Gain expertise in machine learning using the Scikit-Learn package
Learn more at www.simplilearn.com/big-data-and-analytics/python-for-data-science-training
This presentation is for my class to work through as teachers are on a series of PD days. It is based on a very bad One Direction joke cracked in a class about vectors.
I split the presentation for the unit into two, as I added so many slides to help with student questions and misconceptions. This one focuses on mathematical aspects of the unit.
In the first week of High School, my Grade 9 Chemistry class were asked to put on a short show for the BBP and KA students (3-5 year-olds) about water. We used it as a chance to get to know each other and to formatively assess Criterion B: Communication and F: Attitudes in Science.
This is a document used in my EE summer school sessions. After looking at excellent examples of EE's, examiners' reports, the EE guide and subject-specific guidance, students were given this document.
Ideas for integrating inquiry and differentiation with AOI'sStephen Taylor
Jon Schatzky and I have been working on some ideas on this MYP workshop. None of the work presented here is definitive, but some of the graphics might be of use. The editable powerpoint is available for download.
Big thanks to Cameron Hall for his great work on visualising the Areas of Interaction.
One World: Scientific Solutions to Global IssuesStephen Taylor
A one or two lesson formative assessment task to introduce students to One World.
Students watch one of two videos which introduce a scientific solution to a problem in a global context. They then prepare a mind-map poster which goes through the stages of the One World criterion.
This is a work in progress, but outlines some of the ways in which home-made concept cartoons are used in my class. It was featured on the SlideShare homepage.
I highly recommend that teachers, especially in Middle School, get a copy of the concept cartoons resources.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
1. Chemistry Lab ManualName:
_____________
In this task, we will work in groups to learn about the measuring tools in the Chemistry Lab. This
booklet will help you in future tasks and assessments. Record all your work in this booklet.
Submit for checking at the end of the session – it will be formatively assessed for Criterion E:
Processing Data and Criterion F: Attitudes in Science.
Related Concepts:
01.2 Accuracy, Precision, Error, Uncertainty(Quia quiz: http://www.quia.com/quiz/3507626.html)
01.3 SigDigs and Notation(Quia quiz: http://www.quia.com/quiz/3504378.html)
Criterion E: Processing Data
Level Level descriptor
0 The student does not reach a standard described by any of the descriptors below.
1–2 The student collects some data and attempts to record it in a suitable format.
The student organizes and presents data using simple numerical or visual forms.
The student attempts to identify a trend, pattern or relationship in the data.
The student attempts to draw a conclusion but this isnot consistent with the interpretation of the data.
3–4 The student collects sufficient relevant data and records it in a suitable format.
The student organizes, transforms and presents data in numerical and/or visual forms, with a few errors or
omissions.
The student states a trend, pattern or relationship shown in the data.
The student draws a conclusion consistent with the interpretation of the data.
5–6 The student collects sufficient relevant data and records it in a suitable format.
The student organizes, transforms and presents data in numerical and/or visual forms logically and correctly.
The student describes a trend, pattern or relationship in the data and comments on the reliability of the data.
The student draws a clear conclusion based on the correct interpretation of the data and explains it using scientific reasoning.
Criterion F: Attitudes in Science
Level Level descriptor
0 The student does not reach a standard described by any of the descriptors below.
1–2 The student requires some guidance to work safely and some assistance when using material and equipment.
The student requires some guidance to work responsibly with regards to the living and non-living
environment.
When working as part of a group, the student needs frequent reminders to cooperate with others.
3–4 The student requires little guidance to work safely and little assistance when using material and equipment.
The student works responsibly with regards to the living and non-living environment.
When working as part of a group the student cooperates with others on most occasions.
5–6 The student requires no guidance to work safely and uses material and equipment competently.
The student works responsibly with regards to the living and non-living environment.
When working as part of a group, the student cooperates with others.
2. There’s no such word as ‘amount’!
What do you really mean when you say “amount”?
Matter is anything that has mass and volume (takes up space):
We measure mass in kilograms (kg), or grams (g).
We measure volume in litres (l) or millilitres (ml) (sometimes cm3).
But we also describe other quantities:
Time in seconds (s)
Length or distance in metres (m)
Energy in joules (J) or kilojoules (kJ)
Heat/temperature in degrees Celcius (oC) (the SI* unit is Kelvin, K)
Amount of a substance in moles (mol)
Concentration of a solution in moles per litre (M)
Acidity or alkalinity in pH (0 is a strong acid, 7 is neutral, 14 a strong base)
Electrical conductivity in Siemens (S)
*Standard International (SI)units are based on the metric system – numbers that divide easily
into tens and hundreds. Most countries in the world use these units and it makes calculations
more straightforward.
In this activity, we’ll learn how to measure some of these physical quantities using the
appropriate tools in the lab. Complete this lab manual as you go along – you will use it as a tool
throughout the course.
Safety First
We must be safe in the lab at all times. Check that you can find these:
Goggles
Fire blanket What should you do if there is an accident in the lab?
Fire extinguisher
Phone
Do not try to clean up broken glass – MrT will do it.
Safe Bunsen ‘driving license’
How do you turn on the Bunsen?
……………………………………………………………………………………………………
……………………………………………………………………………………………………
What is the ‘safety flame’?
…………………………………………………………………………………………………
…………………………………………………………………………………………………
What is the ‘roaring flame’ and which part is the hottest?
…………………………………………………………………………………………………
…………………………………………………………………………………………………
NEVER point a hot container towards yourself or others.
ALWAYS be careful in the Chemistry Lab!
3. Visual guide to Chemistry Lab equipment
As you work through the tasks, draw some simple diagrams of the lab equipment to help you
remember the names.
Beaker Conical flask Test tube
Tripod & Gauze mat Test tube tongs Wash bottle
Pasteur (dropping) pipette Filter funnel Spatula
4. Units and Uncertainty (Quia quiz: http://www.quia.com/quiz/3507626.html)
All measurements have uncertainties – a range of values in which the true measurement could
lie. More precise measuring tools have a smaller degree of uncertainty.
Significant Digits (or Significant Figures) Tutorial:http://is.gd/sigfigs
We use significant digits to communicate how precise a measurement is – how certain we are in
our measurement. In the example above, there are 4 significant digits.
Significant digits are:
All non-zero digits (and all the zeroes in-between non-zeroes!)
Any digits after a decimal point
But they are NOT:
Leading zeroes, e.g. 0.000345 has only 3 sigdigs: 345
Trailing zeroes with no decimal, e.g. 10,000 has only 1 sigdig
How many significant digits in these numbers? Write these numbers to 3sigdigs:
123.45 _________ sig digits
12420 = _______________
123000 _________ sig digits
1.008 _________ sig digits 0.03209 = _______________
01.67 _________ sig digits
4050.0 = _______________
1000 _________ sig digits
1000.0 _________ sig digits 0.0101010 = ______________
Calculating Significant Digits
We can only report values to the minimum degree of certainty so:
When adding or subtracting, use the number of decimal places of the weakest value.
When multiplying or dividing, use the number of sigdigs of the weakest value.
1. 2.01 - 1.0 =
2. 123 + 456.789 =
3. 1.2 x 3.45 =
4. 34.678 /3.33 =
5. Measuring Volume
We use graduated cylinders to measure volumes of a liquid. We do not use beakers or conical
flasks – the marks on those are estimates only.
We read the volume at the bottom of the meniscus – label it on the diagram.
Observe these different-sized measuring cylinders. Complete the table.
Size Markings every… Recorded volume (ml) Uncertainty (± )
5ml
10ml
50ml
100ml
Which of the cylinders has:
1. The most precise gradations (markings)? _______
2. The biggest uncertainty? _______
Add up the total volume of water in the four cylinders. Present your working and give the answer
to the most appropriate significant digits. Explain your answer.
…………………………………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………………………………..
Measuring Mass
We use digital balances to measure the mass of a substance.
Never get the balance wet or dirty.
Check the range of the balance – do not press on it or add a
mass that is heavier than the maximum. You will break it.
Use a measuring tray or paper on top of the stage. “Zero” it if you need to.
Do not stack balances or drop them.
Choose one known mass and measure it using three different balances. Complete the table.
Balance Range (g) Recorded mass (g) Uncertainty (± ) What is this balance good for?
A
B
C
6. Accuracy, Precision & Errors (Quia quiz: http://www.quia.com/quiz/3507626.html)
There is always an element of error in our measurements.
The accuracy of a measurement is how close it lies to the true value (“correct
answer”). The precision of a measurement is how repeatable that
measurement is.
Which of the dartboards shows:
1. High precision and high accuracy? Top - Middle - Bottom
2. Low precision and low accuracy? Top - Middle - Bottom
3. High precision but low accuracy? Top - Middle - Bottom
Systematic error is an error that is the same for all measurements and can be
adjusted. For example, a digital balance that is poorly calibrated might
measure 0.5g too much each time.
Random error is not consistent between measurements and cannot be
adjusted. For example, errors introduced by using different recording tools or
people.
Which of the dartboards shows:
4. Random error? Top - Middle – Bottom 5. Systematic error? Top - Middle - Bottom
Dartboard diagrams from http://preparatorychemistry.com/Bishop_Book_1_eBook.pdf
Measuring Temperature
Compare the glass thermometer with the temperature probe on the data logger.
Remember: Thermometers and dataloggers are NOT for stirring!
Measure the temperature of the solution/ liquid – NOT the container
Don’t touch the thermometer or probe against the glass
Wait for the temperature to stabilize before taking the reading
Which would you choose to get
Glass thermometer oC (± ) quick readings of a reaction that
changes temperature?
Temperature probe oC (± )
What is a Solution?
A solution is a homogenous* mixture of a substance in a liquid.
The solvent is the liquid, e.g. water or alcohol, which dissolves
the…
Solute, which is the solid, e.g. salt or sugar.
Label the solvent and the solute in the diagram to the right.
*mixtures can be:
Homogenous = evenly distributed, like solutions
Heterogeneous = unevenly distributed, like soup or the oceans.
Beaker from: http://www.wpclipart.com/science/beaker/beaker.png.html
7. Measuring pH
We use pH probes on the datalogger to measure the acidity or
alkalinity of a solution. Strong acids have low pH, neutral pH is 7 and
strong bases have high pH.
Measuring Conductivty
In some solutions, ions form. These are positive ions (cations +) or
negative ions (anions -). When these ions move, they carry electrical
charge, which can be detected with the conductivity probe. A high
concentration of ions will give a high conductivity.
pH scale from:http://www.ec.gc.ca/acidrain/kids.html
Take care of the probes:
Make sure the electrolyte bottle is secure when not being used.
Rinse gently with distilled water between every reading.
Do not stir or shake the probe.
Taking readings:
Submerge the probe and wait for the reading to stabilize
Record the pH to an appropriate level of precision
Record the pHand conductivityof these three solutions:
Solution A B C
pH (± )
conductivity
μS (± )
This symbol means ‘micro’ or one-thousandth.
1 μS = 0.001 S (Siemens is the unit of conductivity)
Conductivity and pH probes need to be calibrated regularly. This avoids systematic error.
What do we mean by systematic error?
…………………………………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………………………………..
8. Scientific Notation (Quia quiz: http://www.quia.com/quiz/3504378.html)
Often we produce measurements or readings with a large number of zeroes. We use scientific
notation to present these numbers in a clear, standard format.
Simple rules:
There is always one digit before the decimal
It always ends x 10x(“times ten to the power of x”)
The value of x tells us how many places the decimal has been moved.
If you are making a large number small, x is positive.
If you are making a small number (less than zero) larger, X is negative.
e.g. 1230000000000 can be written as 1.23 x 1012
The decimal has moved 12 places to the left.
e.g. 0.000000000123 can be written as 1.23 x 10-10
The decimal has moved 10 places to the right.
Expand the following notations:
1.0 X 103= _____________________________
1.0 X 10-6= _____________________________
4.56 X 105= _____________________________
7.01 X 10-4= _____________________________
Record the following in scientific notation to 3 significant digits:
• 12340000 = _____________________________
• 00012340 = _____________________________
• 10101010 = _____________________________
Compare the following measurements:
3.04 x 104 kJ 3.040 x 104 kJ 3.0400 x 104 kJ
…………………………………………………………………………………………………………………………………………..
…………………………………………………………………………………………………………………………………………..