Experiment 1 Effects of Density In this experiment you will observe how the density of various materials affects their vertical arrangement in a density column You will also observe the behavior of ice and water and draw conclusions about the molecular arrangement of each By definition water has a density of 1 gram cubic centimeter However the density of every liquid is not the same This principle is often used in the oil industry to separate hydrocarbons from water Some liquids like oil have densities of around 0 91 g cm3 Such a liquid would float on water because it is less dense Solids also have varying densities causing them to either float or sink in water Materials 1 100 mL Beaker 1 250 mL Beaker 1 50 mL Cooking Oil 1 Cork 1 50 mL Corn Syrup 1 Drop Food Coloring 1 100 mL Graduated Cylinder 1 Plastic Coffee Lid Scissors 1 Washer 100 mL Water You Must Provide Procedure 1 Use the graduated cylinder to measure 100 mL of water and pour it into the 100 mL beaker 2 Add one drop of food coloring to distinguish it from the other liquids 3 Pour the water into a 250 mL 4 Use the 100 mL graduated cylinder to measure 50 mL of corn syrup and pour it into the 250 mL beaker 5 Use the 100 mL graduated cylinder to measure 50 mL of cooking oil and slowly pour it into the 250 mL beaker 6 Once all liquids have been added allow the contents of the beaker settle for a few minutes Observe and record the order of the different liquids in Post Lab Question 1 7 Use the scissors to carefully cut the plastic coffee lid into four pieces 8 Carefully without splashing the liquids drop the washer of the plastic coffee lid and the cork into the beaker Observe what liquid each object settles in Record your observations in Post Lab Question 1 Post Lab Questions 1 Sketch and label what the arrangement of objects and liquids in the beaker 2014 eScience Labs LLC All Rights Reserved Cooking oil corn syrup then normal water 2 Rank the liquids and solids in order of least to most dense and use your results to explain you reasoning Cooking oil corn syrup normal water densities are 930 kg m3 1370 kg m3 1000 kg m3 3 Which of the solid materials used in this experiment would make the best boat Why It would be better if the boats are made up of plastic material and the medium in which it can move very easily is the maple syrup as the density is more among the given liquids easily the boat can move without sinking much 4 Would it be easier to design a boat in a world with oceans of maple syrup than oceans of saltwater What property of maple syrup might prevent boats from traveling in it very effectively compared with in water It would be easier to design a boat in a world with oceans of maple syrup than oceans of saltwater because the property of high density of maple syrup might prevent boats from traveling in it very effectively compared with in water Experiment 2 Buoyant Force and Floating Have you ever wondered why you feel weightless in water If you have spent enough time in the pool you will know that it is possible to lift heavy objects underwater like a person that would require much more effort to lift on land This phenomenon is due to the effect of the buoyant force that acts on solids submerged in liquids In this experiment you will explore the science behind why objects seem lighter in water and will explain this reduction in weight using Archimedes Principle You will also examine buoyancy in a solution of salt water and compare it to that in plain water and will explain your observations in terms of density Materials 1 250 mL Beaker 1 100 mL Graduated Cylinder Measuring Spoon Stick Modeling Clay Popsicle Stick 5 tsp Sodium Chloride Salt NaCl 15 Washers Paper Towels Water You Must Provide Procedure 1 Use the graduated cylinder to measure and pour 150 mL of water into a 250 mL beaker 2014 eScience Labs LLC All Rights Reserved 2 Take a stick of modeling clay and divide it into two equal pieces so that the masses are equal 3 Roll one piece into a ball and place it in the beaker Observe the buoyancy of the ball Record your observations in Post Lab Question 1 4 Remove the ball from the beaker 5 Design a shape for a clay boat so that the boat will float 6 Use the remaining clay to form your boat design Remember you want the buoyant force to be large along with a shape that won t tip over 7 Place your boat in the beaker and observe what happens If your boat doesn t float try out different shapes until you are successful Use these observations to answer PostLab Question 2 8 Once you have designed and built a boat that floats add metal washers to the boat one by one Record how many washers you can add before the boat sinks in Table 1 9 Remove the boat and washers mix five teaspoons of salt into your beaker stir well with a popsicle stick to ensure the salt is even dissolved in the water and repeat Step 8 Table 1 Number of Washers a Clay Boat Can Hold Before Sinking Type of Liquid Number of Washers Plain Water 2 Salt Water 4 Post Lab Questions 1 What did you observe when you placed the ball of clay into the beaker The ball sank quickly to the bottom 2 What were characteristics of the boat design that floated the best Explain why this works and the clay ball fails to float using Archimedes Principle The best design was a boat that was wide and long giving the most surface area This agrees with Archimedes principle that states that upward direction at the center of mass must displace the fluid in order for the object to not sink 3 How much water does an object have to displace before it will float According to Archimedes it has to equal the weight of the fluid that the body displaces pushing it upwards and keeping it floating 4 If your clay boat weighs 005 kg and is floating what is the upward force the water is exerting on the boat Upward force exerted by water will be 0 05 x 9 8 0 49 N 2014 eScience Labs LLC All Rights Reserved 5 How could you improve your boat design to increase the buoyant force without using more clay Use less clay to make the weight less and make it have as much surface area as possible 6 In the second part of the experiment does the boat hold more weight in the regular water or the salt mixture What does this say about the relative densities of salt water and plain water More in the salt mixture this is because the salt water is more dense than plain …
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