Page 127 - Active Science 5 Ebook and Activity

Activity 11.1

Fill half a glass with water. Mark the level of Factual Study

water by sticking a piece of coloured tape on the Water is the only substance
glass. Place the glass in the freezer. After three on earth that exists in all the
hours, take it out. The level is raised, why? three states.

Let’s Recapitulate

Fill in the blanks.

1. Matter is made of tiny units called _______________.
2. ______________ are building blocks of matter.

3. There are three states of matter – ____________, liquid and ___________.
4. In gases, intermolecular space is very _____________.

Heating of Liquids, Solids and Gases

Upon continuous heating, the molecules Factual Study
gain energy and move at an extreme pace. In ancient Greece, a man named
Therefore, they lose contact with each Democritus figured out that every single
other transforming a liquid into gas. This thing in the universe must be made up

process of changing liquid to a gaseous of tiny particles that can’t be cut any
form is called evaporation. Evaporation further. He called these particles ‘atoms’,
causes the water to disappear from a glass, which in Greek means ‘uncuttable’.
wet clothes, etc.

On heating solids, the molecules start to vibrate which on further heating, moves the

particles and transforms the solid into a liquid. This is called melting, i.e., transforming
of solid into liquid. Normally, some solids undergo changes, but not all of them change.
For example, a candle would melt and change into wax on heating.

Activity 11.2

Aim : To understand the result of heating a solid and the concept of
expansion and contraction.

Materials Required : Some wax, a beaker, a burner
Procedure : • Put the wax into the beaker.
Melt Candle
• Then heat for some time.
• Is it flowing like a liquid?

Observation : The wax has expanded. Burner
Conclusion : Some solids expand on heating.

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