Solids, Liquids, Gases Medium Demand Questions 1. Mixing materials Seema and Alan are mixing materials. They put different materials in four clear plastic bags. They tie the top of each bag. They watch what happens and record their observations. Mixture Bag A: Brown sugar and water. Observations Water turns brown and cannot see the sugar after a while. Bag B: Oil and water. Oil floats on top of the water. Bag C: Bicarbonate of soda and vinegar. Lots of fizzing. It looks frothy. Bag puffs up. Bag D: Bicarbonate of soda and oil. Bicarbonate goes in a lump at the bottom. Write the names of the THREE liquids that the children used. (i)... (ii)... (iii)... Look at the table. In one bag dissolving was the only change. In which bag was dissolving the only change?
(c) The mixture in Bag C fizzed and the bag puffed up. Why did Bag C puff up?... (d) Three of the mixtures can be separated to get the starting materials back again. One of the mixtures cannot be separated. Which bag has a mixture that cannot be separated?... 2. Solids and Liquids Helen and Amy put an ice lolly in a dry glass jar. After 105 minutes they saw that the ice lolly had turned to liquid. What is the name of the process when a solid turns into a liquid? They saw drops of liquid forming on the outside of the jar. What is the name of this liquid? Tick ONE box. (c) (d) ice lolly steam water juice mist What is the name of the process which causes this liquid to form on the outside of the jar? Where did the liquid on the outside of the jar come from? (e) A similar ice lolly was placed in a similar glass jar.
They wrapped this second jar in a woollen scarf.
3. Toffee Adrian and his dad are cooking toffee. The pictures below show how they make the toffee. 1. Put a metal tray into a freezer for an hour. 2. Stir sugar into some cold water. 3 Heat the mixture until it turns golden brown. 4 Pour the mixture into the cold tray from the freezer What happens to sugar when it is put into cold water and stirred?... What happens to some of the water when the mixture is heated?... (c) The mixture becomes very hot. Tick ONE box to show what Adrian should measure to find out how hot the mixture is. weight temperature (d) volume time Adrian carefully stirs the hot mixture with a wooden spoon. The handle of the wooden spoon stays cool. Tick ONE box to explain why the handle of the wooden spoon stays cool. Wood cannot get hot. Wood is a poor conductor of heat. Wood is a hard material.
Wood is a poor insulator of heat. (e) Adrian takes the tray out of the freezer. He pours the runny mixture into the metal tray. He leaves the tray on a table for 10 minutes. The mixture becomes solid. Why does the runny mixture become solid?... 4, Water Cycle Some children are learning about the water cycle. The different forms of water are solid, liquid and gas. Put ONE tick in each row of the table below form of water solid liquid gas to show whether each one is solid, liquid or gas. One has been done for you. (3 marks) rain water vapour snow ice Sanjay says, The water vapour rises from the land and sea into the air. It is part of the water cycle. The statements below describe a water cycle. Write the numbers to show the correct order, 1 to 5. Write ONE number in each box. The first one has been done for you.
Water flows back to the sea in rivers. Clouds cool and water droplets form. Water vapour rises from the sea into the air. 1 Water vapour cools and turns back into water which forms clouds in the sky. Droplets of water fall back to the ground as rain. Breathing Nick breathes onto a mirror. mirror It becomes misty. Choose one reason that helps to explain why the mirror becomes misty when he breathes on it. Tick ONE box. The mirror is hotter than his breath. The mirror is colder than his breath. The mirror is the same temperature as his breath. The mirror is dry. Name the process that makes the mist appear on the mirror.
(c) After a few moments, the mist has gone. Nick has not wiped the mirror. What has happened to the mist to make the mirror look clear again?