CBSE Book Class 8 Science Activity Lighter or Heavier

 MATERIALS- METAL AND NON METALS

Karan is a curious student. One day, he put some iron dust in a beaker containing dilute hydrochloric acid. He noticed fumes coming out of the beaker. He got worried and wondered what had happened? He picked  up the beaker to throw away its contents. But, OUCH! It was so hot. His teacher will definitely scold him  now for being careless.

What to do: 

1. Take dilute hydrochloric acid in the glass bottle. 

2.  Put some iron filings or zinc dust in the balloon. 

3.  Fix the balloon on the mouth of the glass bottle so that the iron filings get dropped in the glass bottle.  What do you notice? Does the balloon inflate?

4.  Remove the balloon carefully and tie its mouth tightly without letting the gas escape. 

5.  Release the balloon. Does it rise and float away? What does this indicate? Is the gas trapped in the balloon lighter or heavier than air? Which gas could it be?In the above activity you allowed metal iron to react with an acid. What happens when metal carbonates and bicarbonates react with acids? Let us find by doing an activity.

6.  Take 2mL of vinegar in a glass bottle.

7.  Take a pinch of baking soda in a balloon.

8.  Fix this balloon on the mouth of the glass bottle so that baking soda gets dropped in the glass bottle. Do you notice bubble formation? What happens to the balloon? Remove the balloon and tie its mouth tightly without letting the gas escape. 

Release the balloon. Does it rise and float away? Does it behave the same way as the first gas filled balloon in the first case? Is this gas heavier or lighter than air? Find out from your science teacher how you can test for these gases?

Please refer to the link below - CBSE Class 8 Science Activity Lighter or Heavier