|
Lesson No: 6 Unit Title:
Solutions Unit No: 7H
      
|
|
Lesson Title: Dyeing for juice NC
Ref: Sc3 1h
|
|
Objectives:
MK - What chromatography is, how to
make a chromatogram, how it is used to
separate colours in inks.
SK - How chromatography works, what it is used for, what
a chromatogram is.
CK - Applications of chromatography
DNA
fingerprinting.
|
|
Lesson outline:
MK
-
Review separation techniques covered
so far using slip / sudden death tests.
-
We have looked so far at how to
separate solute from solution, solvent from solution. Sometimes more than one
solute is dissolved in a solvent and we need to know what solutes are in the
solution. Ink is an example of a solution made up from many solutes (dyes).
Students will have done this before at feeder schools.
-
Practical
Students
to do some chromatography with a selection of inks.
SS58
(or
how you would like to do it) shows students the general set up.
-
After doing this with
inks, get them to try it with biro. Let them find out for themselves
that it wont work. Get them to try again using
ethanol instead of water.
-
Exploring Science P98 99 and
7Hd/1 and
7Hd/6
Plenary
-
MK
Chromatography
separates the dyes in inks. We can tell what dyes make up ink by looking at
the colours on chromatogram.
7Hd/1
-
SK Each dye is different in its solubility. As
the solvent spreads out, the least soluble gets left on the paper nearest the
centre while the most soluble will stay in solution until near the end. In
effect we have a solubility gradient.
7Hd/6
-
CK
Applications
DNA
fingerprinting.
(7Hd/7
- extension work)
|
|
|
Homework: MK/SK
- 7Hd/5
|
|
Resources: SS58
7Hd/1
7Hd/5 7Hd/6
7Hd/7 filter paper, scissors, water
soluble
inks, paper clips, glass rods, permanent markers.
|
|
Risk
Assessment: safety glasses. Ethanol is flammable. Watch out for students trying to
write on desks with permanent marker.
|