Density is a property of matter that relates mass (how much matter is in a substance) to volume (space occupied by a substance). Basically, you can think of density as the amount of matter in a given space, or how tightly packed an object's atoms are. If you look at the image below, you will notice that all three circles are the same size, but the amount of matter in each sphere is different. The circle on the left has the least amount of matter (mass), while the one on the right has the most amount of matter (mass). Mathematically, you could calculate the density of each circle using the equation: density = mass/volume. However, you can also look at them and see that the one on the left is the least tightly packed, so it has the lowest density; the one on the right is the most tightly packed, so it has the highest density.
Density isn't just a mathematical concept though. It is also used for determining whether something will float or sink. Objects or liquids with a higher density will sink, while those that are less dense will float. So, how can you use density to stack the liquids in your drinkable density column? Well, you will need to manipulate (change) the density of each of your layers.
Watch the video below if you feel like you need a visual explanation of how density affects an object's ability to float or sink.
Creating a Density Column Drink
This recipe will make approximately four density column drinks with 7 layers each. You can reduce the number of layers if needed though.
Make sure you read the recipe (procedure) completely before you start your density column!
Ingredients:
A "tart" unsweetened or fresh fruit juice of your choice (e.g., pomegranate, cranberry, lime, grapefruit, orange, cherry, pineapple)
Sugar
Water
Food coloring (technically this is optional, but it is helpful for seeing the layers!)
Ice (optional)
Procedure:
Step 1. Make a simple syrup by adding 1 cup cold water and 1 cup sugar to a medium-sized saucepan (or pot). Heat the sugar and water mixture over medium-high heat until it boils. Once it boils, turn the heat down to low and stir constantly until all the sugar dissolves. This should take approximately 3-5 minutes. You will know the sugar is dissolved when the liquid is clear - you shouldn't see any sugar crystals. Set your simple syrup to the side and let it cool to room temperature.
Step 2. Fill four water glasses with ice. (The ice will make it easier to get the layers to stack, but it's not necessary.)
Step 3. To make your first (and most dense) layer, add 5 tsp. of your unsweetened or freshly squeezed juice and 8 tsp. of your simple syrup to a liquid measuring cup. Then, fill the measuring cup to the 1/2 cup (4 oz) line with water, and add the food coloring of your choice. Stir until all the ingredients are blended and then slowly pour your layer into each of the drinking glasses full of ice. You should have an even amount in each glass.
Step 4. Repeat step 3 with 3 tsp. of your unsweetened or freshly squeezed juice and 5 tsp. of your simple syrup.
Step 5. Repeat step 3 with 2 tsp. of your unsweetened or freshly squeezed juice and 3 tsp. of your simple syrup.
Step 6. Repeat step 3 with 1 tsp. of your unsweetened or freshly squeezed juice and 2 tsp. of your simple syrup.
Step 7. Repeat step 3 with 1 tsp. of your unsweetened or freshly squeezed juice and 1 tsp. of your simple syrup.
Step 8. Repeat step 3 with 1 tsp. of your simple syrup.
Step 9. To make your final (and least dense) layer, repeat step 3 with 1 tsp. of your unsweetened or freshly squeezed juice.
Step 10. Step back and admire your layers before drinking them!
Challenge/Extension:
Did you notice a pattern in the amounts of juice and syrup you added for each layer?
If not, look again at the layers below. Do you see it now?
The layers, from least dense (top) to most dense (bottom) were as follows:
1 tsp. juice
1 tsp. simple syrup
1 tsp. juice + 1 tsp. simple syrup
1 tsp. juice + 2 tsp. simple syrup
2 tsp. juice + 3 tsp. simple syrup
3 tsp. juice + 5 tsp. simple syrup
5 tsp. juice + 8 tsp. simple syrup
This recipe is modeling the first part of the Fibonacci sequence!
Watch the videos below to learn more about what makes this sequence so special, then choose one or more of the following challenges to complete.
Challenge #1. Come up with another recipe of your own that uses the Fibonacci sequence.
Challenge #2. Figure out how temperature affects the density of liquids.
Challenge #3. Find flowers and pinecones and see if you can find the Fibonacci sequence in them.
Challenge #4. Practice drawing squares and spirals using the Fibonacci sequence.