CSI



Learning Intentions:

1. To become familiar with //chromatography// and be able to apply it to 'real life' situations.

2. To perform 'fair tests' in Science identifying substances and fibres.

3. Identify and group fingerprints into 3 main categories: Arch, Loop and Whorl.

4. Set up and carry out Scientific Experiments following the correct process of; Aim, Equipment, Hypothesis, Method, Results and Conclusion.

5. Work collaboratively with peers to solve problems using the skills learnt.

Lesson One - Paper Chromatography

Chromatography is a technique used for seperating mixtures. In all of the variations of Chromatography, a substance is placed onto or into a medium and then a solvent passes through the test substance, some of the test substance may be attracted to the solven and follow it up in the medium. Different types of molecules are transported different distances, causing them to seperate. In these activities, filter paper is the medium, solvent is the solvent and black ink is the test substance. Chromatography is used in crime labs to seperate the components of 'clue' substances such as blood, ink or other mixtures found at the scene of a crime. Chromatograms of these clue substances are then compared with those of the suspected sources.

__Chromatography Monday 9th May 2011__

__L.I__ I am learning the process of the chromatography and use this to assist with solving the crime.

__Aim:__ To use chromatography to distinguish which pen was used in the ransom note.

__Hypothesis:__ I think that Casade marker because it looked close to the pen used on the note.

Black marker x5 Casade marker x14 Sharpie x3 Vivid x4

__Equipment -__ Beaker, felt pens, ransom note, filter paper, water, hand lens, masking tape and straws.

Method:

1. Gather samples of pens. 2. Draw a line across a strip of filter paper, 1-4cm from the bottom. 3. Attach to straw with masking tape. 4. Put filter paper in beaker, making sure the ink is at least 1-2cm above the water. 5. Observe. 6. Remove filter when water has travelled about 3/4 of the way up the strip. 7. Compare results with the ransom note results.

Results - 1. Black Ballpoint Pen 2. Vivid 3. Cascade marker 4. Sharpie 5. Black marker

Reflection - That it is not hard at all to find out what pen has been used to write a note. I learned that the Cascade marker will spread a lot and looks really cool. The Black marker does not spread very much.

__Lesson Three - Kitchen Chaos Wednesday 11 May 2011:__

The kitchen cupboard has got very damp and the labels have fallen off some of the containers. From the label scraps it is found that there is:

Icing sugar baking soda salt cream of tartar cornflour

TASK - Make order out of chaos

Use a series of simple tests and good observations to find out what substance is in each container.

Caution: You are not allowed to taste them! Please use small quantities.

Aim: to find out what the substance is by carrying out a series of simple tests.

Hypothesis: I think that the substance in the different containers is;

Substance A - ............................. Substance B - .............................  Substance C - .............................  Substance D - .............................  Substance E - .............................

Equipment - Five containers with the different substances labelled A, B, C, D, E. - Eyedroppers - Vinegar - Magnifying Glass - Litmus Paper (red and blue) - Iodine

CLUES TO HELP YOU.......................

1. Cream of tartar is an acid, and turns blue litmus paper red. 2. Cornflour and sugar are neutral and don't affect litmus paper. 3. Salt and bicarbonate of soda are alkaline, that is they turn red litmus paper blue 4. Bicarbonate of soda fizzes when mixed with vinegar. 5. Iodine changes from yellow-brown to blue-black with cornflour. There are many different ways of telling the differences between substances. You could: Results: Substance A is .......................... Substance B is ........................ Substance C is .......................... Substance D is ..........................  Substance E is ..........................
 * Smell them carefully.
 * Compare the way they dissolve in water.
 * Examine with a magnifying glass.
 * Test the acidity with litmus paper.
 * Test the reaction with vinegar and iodine.

__Lesson 3 - Fossicking for Fuels Friday 13 April 2011:__

__Aim:__ to determine properties of different fibres/materials.

(Record your results on the sheet provided then glue this into your Science book.)

__Equipment:__ 1. 3 different types of material. 2. 2 beakers 3. 3 test tubes 4. Force meter (spring balance) 5. Ruler 6. Felt pen 7. Magnifying glass 8. Tongs 9. Candle

THE TESTS

TASK ONE - HOW MANY FIBRES ARE THERE IN THE MATERIAL?

TASK TWO - WHICH MATERIAL IS THE STRONGEST?

TASK THREE - WHICH FIBRES SOAK UP THE MOST WATER?

TASK FOUR - HOW DO THE MATERIALS BURN?

TASK FIVE - WHICH MATERIALS STRETCH THE MOST?

(Record results on the sheet provided)