Safety in the Lab

• What is different about this classroom and every other classroom in your school?

Safety in the Lab

• Do you think there are any special rules that apply to a Science Classroom?

• Can you write 5 down please

Safety in Science

• How to use a Bunsen burner safely

• How do use chemicals safely

Indicator

To accurately make an indicator and test how well it works

Acids and Alkalis

• What are they?• Where are they used?• How do we know if something is an

acid or an alkali?

Universal indicator has a range of colours that show how weak or strong the acid or alkali is.

stronger alkalistronger acid

What is the colour for a weak acid? What is the colour for a strong alkali?

weak alkali

weakacid

strongalka

lineutral

strongacid

Telling the difference between solutions-Are they an acid or an alkali?

INDICATORS

How can you get the red dye out of the cabbage

looking at the equipment I have and the equipment in the

science room?

IndicatorsAIM- To make an indicatorApparatus :

Red CabbageHydrochloric acid droppersSodium Hydroxide droppersTest TubesWhite TilesVarious different substances to be tested for their pH (lemonade, vinegar , lemon, bleach etc) Household substances as well as scientific solutions (calcium hydroxide, nitric acid, sulphuric acid).Pipetters

Method• Place some red cabbage in a 250 ml

beaker• Add 50 ml of water to the beaker• Heat up under a Bunsen burner until the

dye appears• Pour 1ml in to 2 test tubes• Test each test tube with an acid and an

alkali• What colour does it go in acids?• What colour does it go in alkali’s?

RESULTSSUBSTANCE COLOUR IN INDICATOR

Higher Tier Experiment Write Up

• Aim: To test the effect of different substances on the colour of the red cabbage indicator.

• Independent Variable:

• Dependent Variable:

• Control Variables:

Variables• Experiment:

• Independent Variable:

• Dependent Variable:

• Control Variables:

How can you measure the strength of an acid or an

alkali?

INDICATORS

• Can you name any indicators?

The strength of an acid or alkali is measured by the pH scale.

What is the pH scale?

Each universal indicator colour is given a number called the pH value.

Universal indicator can tell you the pH of a solution.

What is the pH of a weak acid? What is the pH of strong alkali?

weak alkali

weakacid

strongalka

li

strongacid

stronger alkalistronger acid

neutral

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Indicators

• Litmus-

• Methyl Orange-

• Universal Indicator-

• Red Cabbage-

The strength of an acid or alkali is measured by the pH scale.

What is the pH scale?

Each universal indicator colour is given a number called the pH value.

Universal indicator can tell you the pH of a solution.

What is the pH of a weak acid? What is the pH of strong alkali?

weak alkali

weakacid

strongalka

li

strongacid

stronger alkalistronger acid

neutral

1 2 3 4 5 6 7 8 9 10 11 12 13 14

INDICATOR QUESTIONS1. What colour will Litmus go when added to

orange juice?2. What colour will methyl orange go in Sodium

Hydroxide?3. What colour will Red Cabbage go in Hydrochloric

Acid?4. What colour does toothpaste turn Universal

Indicator?5. What colour would methyl orange go in Vinegar?6. What colour will Litmus go in Acid Rain?7. What colour will Litmus go in Sodium

Bicarbonate?8. What colour will Universal Indicator go in tap

water?9. What colour will Methyl Orange go in Soap?10. What colour does red cabbage go in Nitric Acid?