Electrical and Chemical Signals

Aim: Does the colour intensity of a drink affect how sweet it tastes?

Any Questions

?

Method:1) Collect cups, lemonade (of a known

sucrose concentration), red food dye, stirring rod and a measuring cylinder.

2) Measure out 50ml of lemonade into a measuring cylinder.

3) Label the containers A-E.4) Add 1 drop of red food colouring to cup A, 2

to cup B, 3 to cup C, 4 to cup D and 5 to cup E.

5) Stir the different lemonade/dye solutions to ensure an even distribution of food colouring.

6) Ensure that the person tasting the drink does not see the preparation of the drink.

Method Continued…….7) Get the same person to try all of the drinks A-E,

in between each drink they should rinse their mouth out with mineral water.

1) Then they should put the drinks into the order of which one they think is sweetest (A-E).

2) Collect the results in a table and repeat the experiment again with the same person 2 more times.

3) Making sure that you use clean cups each time.4) Then get different people to do the same

experiment and compare the different results.5) Ensure that no-one shares the same cup, cups

are clean and that the equipment used has not been used for any other experiments.

Results Table – Let’s Fill it in as a class………

Number of drops of red food colouring in each

drink.

Number of volunteers who thought the drink

was the sweetest.

1

2

3

4

5

How did you make your experiment reliable?• We repeated our experiment 3 times for each

individual.• We ignored any odd results or repeated them.

How did you make your experiment valid?• We used the same amount of lemonade each time

(50ml)• We used the same lemonade each time (with the same

amount of sucrose in it).• We washed our mouths out with water after each taste

to get rid of any sugary taste• We used clean cups• We measured the amount of food dye used each time

and used the same food dye each time• People should be in the same age range• Same brand of lemonade should be used• Only one colour of food dye is used as this could affect

results• Try not to use other senses like smell as this could

affect the results.

How could you make your experiment even

better??

How would you carry out an investigation to investigate the effect of smell on

taste?

Method (in your own words)………..

1) Collect cups, lemonade (of a known sucrose concentration), blindfold, sugar, stirring rod and a measuring cylinder.

2) Measure out 50ml of lemonade into a measuring cylinder.

3) Label the containers A-E.4) To each bottle add a different amount of sugar.5) Stir the different lemonade/sugar solutions to

ensure an even distribution. 6) Ensure that the person tasting the drink does not

see the preparation of the drink.7) Blindfold a person.8) Get the person to smell a cup of one of the drinks,

then taste it.9) Get the person to rank the drinks in order of

sweetness.

One hundred volunteers were chosen to complete this task. The results are shown in the table. The remainder of the volunteers were unable to detect a difference in the sweetness of the drinks.

How many volunteers were unsure?

5

20

How would you draw a bar chart of your data?

Look at your graph, what do you see?

Transfer your results onto the table issued to you.

Put your name onto the table.I will collect these in.

This table will be given to you during the IAA exam on Monday.

Look at the table of data

5

30

One hundred volunteers were chosen to identify flavours of drinks. The results are shown in the table.

What is on each axis?

Use the information from your graphs and

scientific principles to help you explainwhy being able to see may have

affectedpeoples sense of taste?

What does your investigation tell you about the senses of

sight and taste?

How could you make an experiment looking at how sight affects taste, reliable

and valid?

How could you make a future investigation more…

Reliable:• Test more people (repeat).

Valid:• Use a wider range of people (age,

gender).• Use a placebo/ control to compare

results to.• Control other senses.• Do under lab conditions.

What are the advantages and disadvantages of adding

artificial food colourings to foods?

What are the advantages and disadvantages of adding artificial

food colouring?Advantages:Advantages: Disadvantages:Disadvantages:Mainly to food Mainly to food manufacturers.manufacturers.

Mainly to consumers.Mainly to consumers.

Aesthetics (nice Aesthetics (nice appearance).appearance).

Adding man-made Adding man-made chemicals (unknown).chemicals (unknown).

Make more profit.Make more profit. May be allergic to May be allergic to chemicals.chemicals.

Influences us to spend Influences us to spend money and buy them!money and buy them!

Stain fingers/ teeth.Stain fingers/ teeth.

Could use natural Could use natural colourings.colourings.

Hyperactivity.Hyperactivity.

Adverse effects on Adverse effects on health.health.

Any questions???