Question 24
Materials: Safety goggles; gloves; six beakers with 10 cm³ of each of these substances: distilled water, lemon juice, vinegar, liquid soap, fizzy drink (such as cola) and dilute bleach; Universal Indicator paper; white tile; pH chart; Universal Indicator solution in a dropper bottle.
1. Work in pairs or small groups. Put on your safety goggles.
2. Dip a piece of Universal Indicator paper into the substance in each beaker. Use a different piece for each substance.
3. Place the pieces of Universal Indicator paper on a white tile to dry.
4. Match the colour of each piece of Universal Indicator paper to the pH value on the chart. Record this value in the table.
5. Add three drops of Universal Indicator solution to each beaker.
Caution: Universal Indicator solution is flammable. Keep it away from flames. Wipe any spills as soon as they happen. Wash your hands after doing this activity.
Compare the colours of the substances in the beakers with those of the pieces of Universal Indicator paper. Do the colours match? Use the pH chart to check.
1. Work in pairs or small groups. Put on your safety goggles.
2. Dip a piece of Universal Indicator paper into the substance in each beaker. Use a different piece for each substance.
3. Place the pieces of Universal Indicator paper on a white tile to dry.
4. Match the colour of each piece of Universal Indicator paper to the pH value on the chart. Record this value in the table.
5. Add three drops of Universal Indicator solution to each beaker.
Caution: Universal Indicator solution is flammable. Keep it away from flames. Wipe any spills as soon as they happen. Wash your hands after doing this activity.
Compare the colours of the substances in the beakers with those of the pieces of Universal Indicator paper. Do the colours match? Use the pH chart to check.
