You are not doing anything wrong. Some inks are not soluble in alcohol. It is possible that an ink sample like this could show up on a test.
The rubbing alcohol will already be poured into cup.
Teams should bring their own pencil to suspend the chromatography paper. It can be either round or flat-sided.
Generally, no limit.
The magnifying glass can have a light on it, but one is not required.
It can be any practical size, and there can be an additional magnification, such as having one magnification as the majority of the glass and having a smaller window of stronger magnification.
Microscopes are not allowed.
There is no requirement for the notes to be typed or hand-written. Either will be acceptable. It may have notes on both sides.
There will be at least 6 cups at each station, and students may ask for more if needed.
Points are awarded for identifying the correct suspect(s). If innocent suspects are also named, a fraction of those points are taken off.
The magnifying glass must be one piece, and work without being plugged into an outlet.
A high-scoring chromatogram will have six neat designs that implicate the correct suspect(s) and travel straight up the paper running into each other.
Yes, splash-proof goggles which can fit over prescription glasses are required. There should not be any gap between the goggles and the student's face. Goggles which look like glasses are not adequate.
The fingerprints may not be labeled. Students should learn how to identify them.
The chromatography paper will already be marked.
No. Rubbing alcohol is used only for chromatography.
No. However, it may be beneficial to mention this vocabulary when learning about fingerprints to make it easier to describe them.
Students will be provided one plastic spoon for each cup.
Yes. They will not be scaled.
1 will be for the powders portion
2 will be for the chromatography
3-5 will be for the finger, foot, and tire prints respectively
6 will be for unspecified evidence
7 will be for final criminal implication.
No. The students will be provided everything they need. To see how this will look in the testing room, view the chromatography video we've posted.
The students could be presented with either. If they are physical samples, they will be presented as a microscope slide. If they are photographs, they will be very magnified.
Liquids should be added to the powders in the plastic cups. Students will be provided spoons and extra empty cups to split up their samples and conduct tests on them. The black paper is helpful for looking at dry powders up close.
No. The only written part is the identification of powders.
Yes, any information may be included, provided that it is printed or written directly on the page.
Powder identification is still written and hand scored as before. Every "implication” question utilizes the ZipGrade, and will be labeled to match the form. Students will be given a numbered list of very specific implication questions to avoid confusion. For example, students might be asked which suspect(s) has the same powder(s) on them that were found at the crime scene. Similarly, they could be asked which suspect's ink sample on the chromatogram matches the ink sample from the crime scene.
The ZipGrade scoring system has the ability to score multiple correct answers in the same question. For example, if both B and D are correct matches, the student would be expected to mark both. Students will be expected to select only the correct matches, and may lose points for answering incorrectly.
They might or might not have the same matches. Students should only implicate two criminals if they see two suspects with the same number of implications over all sections.
Yes, however the calcium carbonate provided on the test will be in powder form and uncolored. Keep in mind that chalk may contain extra ingredients besides calcium carbonate.
Tums contains calcium carbonate as the active ingredient, however it will likely contain extra ingredients that can interfere with reactions.
Powdered calcium carbonate is available in bulk from several sources on Amazon at a cheap price. We purchase it this way and it is classified as "food grade" which is 97% pure ground limestone.
You may also find it at some pharmacy stores in powder form, or you may have to buy it in tablet form and crush it.
Chalk can be a viable substitute if it is pure calcium carbonate.
All powder mixtures will be well mixed together.
Students may lose points on chromatography quality and neatness of their test. Perfect chromatography experiments will have straight ink lines from the wicking alcohol, and not over exposed (around 10 minutes is ideal) so the ink colors are nice and sharp looking.
Students are not allowed to smell the liquids.
Here is the approximate breakdown, this can change by up to 15%
Powder identification 40%
Crime Analysis 50%
Cups will be filled with about 15 grams of powder total. Teams will be given an excess of water, vinegar, and iodine. Students should learn to only use drops of water, vinegar, and iodine when experimenting.
The test will be age appropriate.
For example, blood found at the crime scene could be from the criminal accidentally getting a paper cut while committing the crime. No blood spatter analysis or other information relating to violent crime will be included. Students could be required to match characteristics of blood, such as blood types and DNA.
Students will be scored on their ability to name all powders in all six cups. There is a handwritten portion of the test for this, separate from the Scantron portion.