5. Complete Activity 5.5 (Page 48). Hold a used hack-saw blade with a pair of tongs. Keep the tip of the free end of the blade on the gas stove. Wait for a few minutes. Does the colour of the tip of the blade change? Remove the blade from the flame. Observe the tip once again after some time. Does it get back its original colour?
Answer: The above activity can be carried out as follows:
Aim: To observe if the colour of the blade tip changes on contact with the stove and conclude based on that.
Materials Required: Hack-saw blade, tongs, gas stove.
Procedure:
(i) Using a pair of tongs, hold the tip of the free end of the blade on the gas stove.
(ii)Wait for a few minutes and observe if the colour of the tip of the blade changes.
(iii) Next, remove the blade from the flame, wait for some time and observe the colour of the tip once again.
Observations:
On contact with the gas stove the colour of the blade tip glows red. On removal from the stove the blade tip stops glowing and retains its original colour after some time.
Conclusions:
The colour of the blade tip changes. Colour is a physical property. Hence, the change is a physical change.
“Complete Activity 5.5 (Page 48). Hold a used hack-saw blade with a pair of tongs. Keep the tip of the free end of the blade on the gas stove. Wait for a few minutes. Does the colour of the tip of the blade change? Remove the blade from the flame. Observe the tip once again after some time. Does it get back its original colour?” – Solved.
Related Links:
Solution to Extended Learning – Activities and Projects Question 1
Solution to Extended Learning – Activities and Projects Question 2
Solution to Extended Learning – Activities and Projects Question 3
Solution to Extended Learning – Activities and Projects Question 4
Solution to Activity 5.1
Solution to Activity 5.2
Solution to Activity 5.3
Solution to Activity 5.4
Solution to Activity 5.6
Solution to Activity 5.7
Solution to Activity 5.8
Solutions to Chapter 5 Physical and Chemical Changes
