1 41 To measure the density of a block of modelling clay, we carried out this experiment: We weighed it on some scales: 27.6 g. We put it into a graduated cylinder containing 120 mL of water. The water level increased to 140 mL. a) Calculate the density of the modelling clay. b) If the block of modelling clay were half the size of the previous one, what would the mass and volume results be? What would the density be? 42 Objects sink in a liquid whose density is lower. Objects float on a liquid whose density is higher. Oil is less dense than water. The denser liquid goes to the bottom. Order the candle, cork, rubber, water and oil from the lowest to the highest density. 43 In an experiment to measure the density of sugar, we obtained: Mass of the empty graduated cylinder: 130 g. Mass of the graduated cylinder containing the sugar: 198.5 g. a) What is the density of the sugar? b) Compare this procedure with case B on the previous page. Why don’t we follow the same steps if sugar is also a solid? 44 The density of milk, water and oil is given below. Calculate the mass of 1 L of each one and complete the table in your notebook. Density (g/mL) Mass of 1 L Milk 1.04 … Water 1.00 … Oil 0.92 … 45 Take an empty drink can and put it in a bowl of water so it floats. Then flatten it as much as you can and put it back in the water. Does it still float? Which of these statements provides an explanation? a) The flattened can weighs more than the empty can. b) The flattened can is denser than the empty can, which contains air. A C T I V I T I E S Is it worth separating waste at home? Some people think that the waste we separate into dif ferent bins is mixed together again when it is collected and transported , so there is no point in separating packaging, glass and paper at home. However, after our waste separation , this separation and recycling process continues in the recycling plants. It is important that we separate waste before we throw it away. T R U E OR FALSE ? 25
RkJQdWJsaXNoZXIy