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Science 4th Lesson

Science Tuesday 2nd March 2021

Still image for this video

Tuesday 2nd March 2021

L.C. to use scientific terms to explain changes of state


Yesterday we looked at the 3 different states of matter : Solid, Liquid and Gas


Materials can change from 1 state to another. Today we are going to look at change in states between Solid and Liquid and Liquid and gas.


Changes between Solid and Liquid?




Freezing occurs when a liquid cools down. The warm liquid loses heat to the cold air. This heat transfer occurs until no energy is available for the particles to slide past each other. This forces them to remain in fixed positions. This way liquid is changed into solid. The temperature at which it occurs is known as the freezing point.


Water ------------> Ice




If a solid is heated to a high enough temperature, it will turn into a liquid. When the solid is heated, the particles gain more energy. This allows the particles to move away from each other rather than sticking together. The melting point is the temperature at which a solids change to a liquid.


Ice ------------> Water


Watch the video on the BBC bitesize link below.



Changes between Liquid and Gas?




If a liquid is hot enough, it starts to boil. Bubbles of vapor are formed. This happens as particles of liquid water gain enough energy to completely overcome the force of attraction between them and change to the gaseous state. The process in which a liquid boils and changes to a gas is called evaporation. The temperature at which a liquid boils is its boiling point.


Water ------------> Steam




This is when the evaporated water (vapour) comes into contact with cooler surfaces.  It cools and loses energy. The cooler water particles no longer have the energy to overcome the forces of attraction between them. They come together and form droplets of liquid. This process in which a gas changes to liquid is known as condensation.


Steam ------------> Water


Watch the video on the BBC bitesize link below.



Your Activity


Activity 1

Label the diagram on Seesaw.


Activity 2

Fill in the blanks within the text. Page 2 on Seesaw.