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Water & Changes of State. Boiling, Evaporation & Condensation P6 Science Extra Class 4 May 2011. How much do I know?. Concept Map. STEAM. to become. ICE. Boils at 100 0 C. into. gains heat &. loses heat &. loses heat &. Freezes at 0 o C. into. WATER. gains heat &. Condenses
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Water & Changes of State Boiling, Evaporation & Condensation P6 Science Extra Class 4 May 2011
Concept Map STEAM to become ICE Boils at 1000C into gains heat & loses heat & loses heat & Freezes at 0oC into WATER gains heat & Condenses (no specific temp) gains heat & loses heat & into Evaporates below 1000C melts at 0oC WATER VAPOUR into
1 (a). Safia and Josh are doing experiments with ice cubes.First Safia puts ice cubes on a plate over a bowl of hot water After some time, Safia sees droplets of water drip from underneath the plate. Water from the melting ice cannot pass through the plate and the bowl has not moved. Explain how the water droplets formed in the bowl underneath the plate. __________________________________________________________ Hot water evaporates into water vapour and loses heat as it touches the cooler surface to condense into the water droplets underneath the plate.
(b)In winter, people put salt on the road to make the ice melt. Josh investigates the effect of salt on melting ice. He puts the same amount of ice in two funnels.He adds salt to the ice in one funnel. The ice starts to melt. Every ten minutes, Josh measures how much water is in each cylinder. The graph below gives Josh’s results.
One axis on the graph has been labelled.Write the label and the units for the other axis. Time (minutes)
Ice melts more quickly when salt is added. (c)What has Josh found out about the effect of salt on melting ice? (d)Josh concludes ‘The more salt I add, the steeper the line on the graph will be’. Josh’s results on the graph do not support his conclusion. Explain why his results do not support his conclusion. _____________________________________________ _____________________________________________ He did not try different amounts of salt.
Rose sets up a test to find out if more water or more vinegar evaporates over 3 days. She puts water in one container and vinegar in another container, like this: 2. (a) Rose knows that water and vinegar evaporate.
Rose places both containers on the same windowsill. (i) Use the information above to describe ONE thing that is not fair in her test. The containers are of different sizes / there is more vinegar than water (ii) Why does it matter if her test is not fair? The results will not be reliable and she will not be able to interpret or compare her results/ know that the results are the true results of her test. (The results will not be accurate – 0m)
(c) Rose changes her test to make it fair. She measures the volumes of water and vinegar twice each day to see how much has evaporated. The table below shows her results.
Rose wanted to compare water and vinegar to find out which evaporated the most over 3 days. Use Rose’s results to write an observation for her test. More vinegar than water evaporated over the three days. • Rose notices that more water and vinegar evaporated between 10am and 3pm on Tuesday than between the same times on Monday or Wednesday. • Suggest ONE possible reason why more water and vinegar evaporated on Tuesday. • Air temperature increased/ it was hotter/ It was more windy/ Less humid/ Cooler on Monday.
5. The diagram below shows particles in a gas, a solid and a liquid.Each arrow, A, B, C and D, represents a change of state.
Choose from the following words to complete the sentences below. boilingcondensingevaporating filteringfreezingmelting • Change of state A is called Evaporation/ boiling • Change of state B is called melting • Change of state C is called freezing. • Change of state D is called condensing
8. The graph shows the temperature change of pure water in a beaker that was left on a table in a room over a period of time. (a) Based on the graph, explain why the temperature of water stopped decreasing after the second minute. 100 The temperature of water has reached the temperature of the room/ surroudings. Temperature (oC) 80 60 40 20 Time ( min) 2 4 6 8 10 12 14
(b) A heat source was introduced at the 6th minute. The water boiled after heating for four minutes. The heat source was removed at the 12th minute. Complete the graph until the 12th minute.
100 Temperature (oC) 80 60 40 20 Time ( min) 2 4 6 8 10 12 14