Page 104 - Innovator's Science-8

exist in different states—solid, liquid, and gas—depending on its
temperature. The particles of water stay the same during these changes;

they just move differently. For example, in ice, the particles vibrate closely
in fixed positions. In liquid water, the particles move more freely and can
slide past each other. When water turns into vapor, the particles move very
fast and spread apart. These changes between ice, water, and vapour are

called physical changes because the water itself does not change
chemically. Now, if we pass electricity through water, we can observe how
electricity affects these particles in a new way.

Activity-3 Aim: To demonstrate that water is made up of Test tubes
hydrogen and oxygen using electrolysis.
Experiential Learning Water
• Collect two small test tubes, a beaker or a
glass tumbler, and a 9 V ba ery. Test tube
stand
• Fill 2/3rd of the beaker with water and add a
few drops of dilute sulfuric acid to it.
• Fill both the small test tubes completely (a) Test tubes filled with water
with water taken from the beaker.
Beaker
• Place a 9 V ba ery inside the beaker
• Without spilling the water, carefully place Water
Science the water-filled test tubes on each of the 9 V
Bytes
terminals of the ba ery. battery
Observation (b) 9 V battery placed inside
• Wait for a few minutes. the beaker containing water
The process of spli ng
water into hydrogen and • Do you observe the forma on of any
oxygen using electricity is gas bubbles at both the terminals Water filled
test tube
called electrolysis. It was inside the test tubes? placed on the Water filled
test tube
first demonstrated by terminal of the placing on
the terminal
William Nicholeson and • Let it con nue for 10–15 minutes. battery of the battery
Authony Carlisle in 1800. Observe the volume of gas collected in
each test tube.
• Is the volume of the gas collected the
same in both the test tubes?

• Remove these test tubes one-by-one (c) Water filled test tubes placing over
the terminals of the battery
carefully. Hydrogen gas
• Test these gases one-by-one by Oxygen gas
bringing a burning candle close to the
Test tube
mouth of the test tubes.
Gas bubbles
• What happens in each case? Which Water containing
gas is present in each test tube? a few drops of
sulfuric acid
9 V battery
(d) Gases collected in the test tubes
Passing electricity through water

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Science-8