Embed a running copy of this simulation. Use this HTML to embed a running copy of this simulation. You can change the width and height of the embedded simulation by changing the "width" and "height" attributes in the HTML. Embed an image that will launch the simulation when clicked. Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Visualize the relative number of hydroxide ions and hydronium ions in solution.
Switch between logarithmic and linear scales.
How to Conduct an Effective Investigation
Investigate whether changing the volume or diluting with water affects the pH. Or you can design your own liquid! Share an Activity! Translate this Sim. Macintosh Systems: macOS Linux Systems: Not officially supported. Please contact phethelp colorado. The PhET website does not support your browser. We recommend using the latest version of Chrome, Firefox, Safari, or Edge.
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Original Sim and Translations About. Topics pH Dilution Concentration Acids Bases Description Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral.
Sample Learning Goals Determine if a liquid is acidic, basic, or neutral Place acids or bases in relative order Describe on a molecular scale, with illustrations, how the water equilibrium varies with pH Determine concentration of hydroxide, hydronium and water at a given pH Relate liquid color to pH Predict qualitatively and quantitatively how dilution and volume will affect the pH and concentration of hydroxide, hydronium and water Version 1.
For Teachers. Teacher Tips Overview of sim controls, model simplifications, and insights into student thinking PDF.Hi Rache, I am an audit manager in Karachi, Pakistan and have been recently transferred to forensic audit.
I have read your blog and would like to discus with you more about framework, process, tools, techniques, etc. Hope to here from you soon. Hi Aamer Sorry for the late reply, I don't check up on comments that often I am not an expert on forensic investigations, this was a course that I studied and decided to share it with the world. I still have my books, and I am willing to answer any questions that you need.
Let me know. Hi Rache I am currently studying Forensic Auditing, and was hoping that you or anyone reading this comment would be so kind as to assist me please with a question. You decide to gather further information about him. Discuss the applicable phase of the crime investigation process dealing with this matter and other related aspects. I am not sure in which of the phases set out above this will fall into. Can you please drop me an email at sephiroth mweb. This assignment is my final one and i would like to give it my all.
Regards Jaco. If the accountant or a person in question is told to corporate with the audit and he agrees but the forensic auditor doesn't even contact the person, the forensic auditor finds damning information about the person in question.
This is nice post which I was awaiting for such an article and I have gained some useful information. Thanks for the great content. It is nice to go through the process at a high level. I am glad to learn this valuable information Private Detective Malaysia. It has been just unfathomably liberal with you to give straightforwardly what precisely numerous people would've promoted for an eBook to wind up making some money for their end, basically given that you could have attempted it in the occasion you needed.
It is really a great work and the way in which you are sharing the knowledge is excellent. Thanks for your informative article trademark assignment in india. Thursday, August 19, Five Phases of an Investigation. First receipt of allegation and mandate to investigate: Internal and external forensic auditors have to ensure that a mandate for an investigation is obtained. Internal auditors need a signed letter of instructions from their employers, to obtain clarity in an investigation and protect the forensic auditor, and it can be presented to a witness to prove the identification of the forensic auditor.Editor's note: At many companies, small security staffs mean other departments—commonly human resources or legal—necessarily help conduct investigations.
The following is an abridged excerpt on the planning phase of an investigation. The objective of an investigation is to get the facts so that a resolution of the complaint and situation can be achieved. At the same time, it is possible that some day a jury or attorneys outside the organization might scrutinize every aspect of any investigation conducted. For example, the organization might have to turn over to outside attorneys every note the investigator has written about the investigation, and the investigator might have to recount every conversation he or she had involving the investigation.
Thus, an investigation is not something that should be done haphazardly or without a clear plan in mind. Many investigators have declared their embarrassment to me when I have reviewed their investigation file two years after the investigation in preparation for a deposition or trial testimony. What seemed like a perfectly reasonable investigation plan at the time is impossible to decipher later. Because every part of an investigation might later be subject to scrutiny, every part of the investigation should be documented, including the up-front planning process.
The following considerations should help the investigator plan an investigation.
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This, in turn, should lead to more accurate and complete information obtained and greater legal protection for the organization. As the investigator begins thinking about how to conduct the investigation, he or she must confront the possibility that certain witnesses to the investigation might feel intimidated by the alleged wrongdoer, even by the simple fact that the alleged wrongdoer is in the workplace.
Even worse, the alleged wrongdoer and even the complainant might intimidate, harass, or retaliate against witnesses in an attempt to influence the outcome of the investigation. It might be necessary to remove the alleged wrongdoer, the complainant or both individuals in order to maximize the information obtainable from other witnesses.
On the other hand, removing an employee from the workplace during an investigation is a serious human resources matter.
If the investigator believes that removing an employee from the workplace is necessary to remove possible intimidation, he or she should consider consulting with the need-to-know group to obtain a consensus on such an action. Interviews often will constitute a major part of the investigation, and it could be a serious mistake to conduct significant interviews one-on-one.
If the organization has two witnesses to interview who have similar recollections, it will be more difficult for the plaintiff to attack the credibility of the investigation. Moreover, it is extremely difficult to ask intelligent questions, listen closely to the answers, formulate follow-up questions and take accurate notes all at the same time. A solution would be to have two interviewers, where one interviewer is responsible for the questioning and the other interviewer is responsible for note-taking.
The note-taker also can ask follow-up questions that the primary questioner might miss. This division of responsibility should remain consistent throughout the interview process. Two interviewers will give you two different perspectives on the situation. Many difficult investigations require tough credibility judgments and it would be valuable to know, for example, that two interviewers have different perspectives on the credibility of a key witness.
Many times, the organization can avoid liability for wrongs committed by its employees, even supervisory employees, if management takes quick and appropriate action to remedy the situation. Thus, it is always desirable to conduct the investigation promptly after becoming aware of the issue.
Impress upon others the need to investigate and resolve the issue quickly and obtain the cooperation necessary to have interviewees available. Of course, if the investigation becomes more complicated than anticipated or unanticipated delays occur, extend the deadline if necessary to do a complete investigation. The investigator must determine whether to provide the complainant with a confirmatory memorandum.
This frequently is desirable when the complainant raises a verbal complaint. The memorandum serves a variety of purposes. Most importantly, it provides the complainant with a clear understanding of the expectations that the organization has for him or her during the investigation.
A letter to the complainant should include the following items:. A request that the complainant add, delete or correct the facts summarized and a confidential means to provide this information. A statement identifying the investigator s and confirming that the complainant has agreed the investigator s will be fair and objective.
If the identity of the investigator s was not previously known to the complainant, the letter should include a statement that the complainant finds the investigator s to be fair and objective unless the complainant indicates otherwise.Use Advanced Search to search by activities, standards, and more. When describing location, it is common to mention the city, state, or country as a location descriptor.
It is also common to talk about landmarks that may be nearby. Another way to describe location is to use reference lines to describe coordinates, or absolute position, on the globe. Two types of imaginary reference lines are used to locate positions or points and to make accurate globes and maps. These lines are called parallels of latitude and meridians of longitude. Two of these imaginary reference lines, the equator and the prime meridian, are called primary reference lines because they are where we start the numbering system.
The earth rotates daily about its axis. The north and south poles are the two imaginary points where the axis would enter and exit from the earth if the axis were a pole or a line see Fig. The equator is the imaginary primary reference line drawn around the earth halfway between the north and south poles.
The half of the earth to the north of the equator is the northern hemisphere ; the half to the south is the southern hemisphere Fig. The prefix hemi- means "half"; thus, hemisphere means "half-sphere.
Movement toward the North Pole is northerly in direction. Movement toward the South Pole is southerly in direction. Degrees of latitude are measured from an imaginary point at the center of the earth.
If the earth was cut in half, this imaginary point would be intersected by a line drawn from the North Pole to the South Pole and by a line drawn from the equator on one side of the earth to the equator on the other Fig. A radius is a line drawn from the edge of a circle to its center. To calculate the angle, draw a line from the point to the center of the earth and a line from the equator to the center of the earth Fig. Parallels of latitude are imaginary reference lines that form complete circles around the earth parallel to the equator and parallel to each other.
Every point on a parallel of latitude is the same distance from the equator, and thus the angle formed between the equator and the latitude line is constant. This is shown in Fig. Parallels of latitude are circles of different sizes see Fig. The largest parallel is at the equator, and the parallels decrease in size towards the poles. The greater the distance from the equator, either north or south, the higher the latitude.
Meridians of longitude are imaginary half-circles running from the North Pole to the South Pole. They are sometimes called lines of longitude. Unlike parallels of latitude that are different sizes, all lines of longitude are the same length.The colours associated with each number correspond to the colour that universal indicator turns in solutions of that particular pH.
On a simple level, the pH scale can be thought of as a ranking of the amount of hydrogen ions in a solution: the more hydrogen ions, the lower the pH number. Looking at the graphic above, you can see that an increase in pH of one point actually involves a tenfold decrease in the concentration of hydrogen ions in a solution.
Why do we bother with this mathematical manipulation in the first place? A pH of spot on 7 denotes a neutral solution neither acidic or alkaline. Any pH below 7 is acidic, whilst any pH above 7 is termed alkaline. Water molecules have the chemical formula H 2 O. In a neutral solution, the concentrations of these two ions are equal. However, the addition of an acid or alkali can cause them to vary. Another common misconception about pH concerns the human body. However, this has no effect on the pH of our body, or, more specifically, our blood.
If we were able to purposefully change the pH of blood outside of this small range, we could actually cause ourselves a good deal of harm; even a pH change of 0. Luckily, the food we eat has next to no effect on blood pH. What we eat can affect the pH of our urine. The pH of urine has an average value of around 6, but can range between 4. Concentration is a measure of how much of a substance is dissolved in a solution.
Since concentration of solutions can easily be varied, solutions of varied concentration of the same acid can have different pH values. Some acids, however, are stronger than others. Hydrochloric acid, the same acid found in stomach acid, is a strong acid as it can easily split up into its component ions.
Always nice and instructive graphics as usual! Just one little point : negative values or values above 14 should be mentioned or at least one should give the impression that pH scale does not end at zero or Thank you. This is an excellent resource for high school chemistry and the introduction of acids and bases.
I particularly like the columns showing the concentrations of the two ions. Thanks for the great chart. Are the two terms synonymous or is there some distinction? In the UK, we use both — a base is used to describe a solid that reacts with an acid, such as a metal oxide. An alkali is a base that is soluble in water. So all alkalis are bases, but not all bases are alkalis!
Acid and alkaline graphics are a staple in many science labs and I predict that this graphic will be useful to many. Another great post.
Gorgeous and informative as always.This is an example of a common experiment used to classify material which should help you to understand how to work scientifically. To classify some mystery substances as acids or bases. Acids and alkalis are irritants. If they get onto your skin, rinse them off. Substance A is neutral and has no effect on acids or alkalis. B is a soluble acid, so it could be a non-metal oxide. C is an insoluble base because it neutralises an acid, so it might be a metal-oxide.
D is an acid solution. E is a soluble base, so it dissolves to make an alkali. F is also an alkali. Classifying materials This is an example of a common experiment used to classify material which should help you to understand how to work scientifically. Aim of the experiment To classify some mystery substances as acids or bases.
Method If the substance is a liquid, add three drops of universal indicator and compare the colour to a colour chart. If the substance is a solid, try to dissolve it in some water and then test its pH. Test to see what effect the substance has on the pH of an acid or alkaline solution to see if it neutralises it. Colour chart of universal indicator colours at different pH values Risks Acids and alkalis are irritants.
Evaluation Your measurements are accurate if they are close to their true value. Your measurements are precise if they are similar when completed again. Your experiment is repeatable if you get precise measurements when it is repeated.
Your experiment is reproducible if others get precise measurements when they repeat it. No change. Neutralises alkali. Neutralises acid.Indicators, Paper, and Meters. It is measured on a negative logarithmic scale from 0 to Acidic solutions are below pH 7, with 0 being the most acidic.
Basic solutions are above pH 7, with 14 being the most basic.The Perfect Crime - Scientific Fraud in America
A solution with a pH of 7 is considered neutral. An example of a neutral solution is pure water at room temperature. In the science classroom, there are many activities that require pH testing.
They include chemistry titrations, environmental science water quality testing, and biological processes labs. As science teachers plan these activities, they may be overwhelmed by the variety of testing options available, including liquid pH indicators, pH test papers, and pH meters. Some activities clearly specify the type of measurement tool to be used, while others do not.
Read on for information about pH indicators, pH test papers, and pH meters. Liquid acid-base indicators are weak organic acids or bases that present as different colors in their acid and base forms.
An indicator has a specific pH range over which it changes from its acid form to its base form. An indicator is not useful outside its pH range because the indicator does not change color over these pH values. Some of the most widely-used pH testing tools are pH indicators, including phenolphthalein range pH 8. Universal indicators are mixtures of several different pH indicators that extend the pH range over which they operate.
Acids, Alkalis, and the pH Scale
Bogen universal indicator is a mixture of methyl red, bromthymol blue, and phenolphthalein, and indicates on a wide pH range of 4. Liquid indicators are especially useful in acid-base titrations, where a noticeable pH change occurs near the equivalence point.
Select a pH indicator whose pH range falls within the pH change of the reaction. This method of measuring pH is quick, inexpensive, and easy. There are drawbacks to using pH indicators. The test sample should be fairly colorless to clearly see the indicator's color change. Also, the indicators inherently measure pH at a low accuracy. Litmus paper is probably the most familiar pH paper.
It is used to broadly test whether a solution is acidic or basic and comes in 3 types—red, blue, and neutral.