Fill the aquarium or sink almost to the top with water. Place a can of regular soda into the water. Make sure that no air bubbles are trapped under the can when you place it in the water. Does it sink or float? Repeat the experiment with a can of diet soda. Does it sink or float?
The cans of soda have exactly the same volume, or size. But their density differs due to what is dissolved in the soda. Regular soda contains sugar as a sweetener. If you look at the nutrition facts on a can of regular soda, you will notice that it contains sugar...a lot of sugar. In some cases a 12 ounce can of regular soda will contain over 40 grams of sugar. Diet sodas, on the other hand, use artificial sweeteners such as aspartame. These artificial sweeteners may be hundreds of times sweeter than sugar, which means that less than a few grams of artificial sweetener is used in a can of diet soda. The difference in the amount of dissolved sweeteners leads to a difference in density. Cans of regular soda tend to be more dense than water, so they sink. Cans of diet soda are usually less dense than water, so they float.
Why does a can of Diet Coke float on water while a can of regular Coke sinks Do…
Many science teachers perform a demonstration in which they immerse sealed cans of Coke and Diet Coke in a tank of water. The can of Coke immediately sinks, while the can of Diet Coke floats. Some instructors have adapted this demonstration as an experiment to teach students the principles of density and buoyancy. The experiments allow students to conduct measurements so that they can devise a scientific explanation for the observed behavior.
Whether an object sinks or floats depends on its buoyancy. An object placed in water exerts a downward force on the water. The water, however, pushes back. Archimedes' principle states that the buoyant force exerted by water or any other fluid on an object is equal to the weight of the water displaced by the object. If the weight of displaced water exceeds the weight of the object, the object floats. Otherwise, it sinks. This, in part, explains why metal ships float. It also explains why the can of Diet Coke sinks. Because the two cans exhibit identical shapes and sizes, they displace equal amounts of water when submerged. But the fact that the can of Coke sinks means it must weigh more than the amount of water it displaces, whereas the can of Diet Coke weighs less.
Remember the other day when I posted about density and wanting something new? (If not, it was a great post [with a freebie!] about creating your own lava lamps. You can check that post out here.) Well, my husband reminded me that we use to entertain our masses with the magic of the floating diet coke!
Objects and liquids float on liquids of a higher density and sink through liquids of lower density. The LEGO brick falls through the oil but floats on the water, while the coin sinks through both. The coin is therefore more dense than both the oil and the water. The plastic bug floating on the oil is less dense than both.
Did you know that if you reduce the density of an object that sinks in water, it will float? We tried this with a heavy ball and used bubble wrap to make it less dense. The addition of the bubble wrap made the ball float!
Some of my favourites are our Fairy Tale Activities, where you can make a raft for the Billy Goats and a Zip Line for Jack and the Beanstalk. The infamous coke and mento explosion is always great fun to watch, and our water science experiments will keep you busy for weeks!
Another great demo for teaching density would be with pop. What you need is a fish tank full of water, a diet coke, and a regular coke. When you put the two cans in the water, the diet coke will float and the regular coke will sink. Explain to the kids that since the diet coke does not have as much mass, it is less dense so it floats.
The materials required for this science fair project:- 1 empty aquarium tank- 1 pail of tap water (we will use about 5 liters)- 1 can of regular coke- 1 can of diet coke- 1 kg of sugar
1. For this experiment, the independent variable is the density of the regular coke and diet coke. The dependent variable is whether the can will float or sink in water. This is determined by observing the cans after they are placed in the water. The constants (control variables) are the density of the water, the temperature of the water and volume of the tank.2. The water tank is filled with 5 liters of water. The depth of the water in the tank must be at least 150mm. 3. The cans of regular coke and diet coke are placed in the water.4. Observation is made to ascertain whether the cans float or sink in the water - these observations are recorded in the table below.5. The 1 kg of sugar is dissolved in the water inside the fish tank.6. Observe whether the cans float or sink in the water and record the finding in the table below.
The density of water is 1.0 g/ml. The regular coke can has a density higher than that of water and therefore it sinks in the water. The Diet Coke has a density that is the same as water and therefore floats in the water.When 1kg of sugar is added to 5 liter of water, the water's density becomes,1.0 g/ml + 1000g/5000ml = 1.2 g/mlAfter the sugar is added to the water, the density of both the cans becomes less than the sugared water. Therefore both the cans will float in the tank.
This activity goes along with the Science Lesson Plan I taught in Practicum B to the second grade class I was working in. The Discrepant Event Demonstration was done to show students that regular Coke sinks while Diet Coke floats. It was fun to do with the students because both sodas were in the same size cans, but have different ingredients in each. Attached below are the documents for the students (worksheets they fill out) as well as the teacher handout.
Carefully place a regular soda in the bowl. It should sink and stand up-right in the bowl. Then place a diet drink in the bowl. It should turn slightly sideways and float a little. Do this again with the others. See if the children can figure out which cans are sinking, which are floating, and why. The regular soda cans should sink while the diet cans of soda should float. Regular soda is made of sugar and is heavier than the ingredients used to sweeten diet sodas. Therefore, those cans will sink in a bowl of water. 2ff7e9595c
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