Want a preview of a QuantumCamp in-class lab? Try this one at home! This lab is part of our Geochemistry course where students learn about the property of density to help classify rocks and minerals.
Before we start, there’s an really interesting measurement scientists use to define the relationship between an object’s mass and volume (make sure to check these terms out if you haven’t heard of them before!) The term used to define the relationship between mass and volume is called density - it’s a way how describe how heavy an object is, compared to it’s size! You can find density by dividing an object’s mass, by its volume!
Density = Mass / Volume
In this experiment, we’ll measure and calculate the density of several liquids, in order to rank and predict the order they will settle in a cylinder.
Small cups (1 per liquid you’ll be testing)
Assorted food coloring
Liquid measuring cup
Clear hollow cylinder or vase
Household liquids (grab at least 3):
Salt (for making salt water)
- Mix a solution of salt water for the activity - start with ¼ cup of warm water, and stir in as much salt as you can until the water looks cloudy.
- Add food coloring of different colors to the rubbing alcohol, water, and salt water.
- Optional: If you have a small food scale, measure the weight of each liquid and subtract the weight of the cups (see table below where we provide these measurements).
- Measure out 1/4 cup or 60mL of each liquid into a small cup
- Make sure between each measurement to wash and dry your measuring cup!
- Optional: Calculate the density of each liquid by dividing mass by volume.
|Salt Water||60.7g||1/4 cup|
|Baby Oil||49.0g||1/4 cup|
|Vegetable Oil||53.7g||1/4 cup|
|Corn Syrup||80.8g||1/4 cup|
|Dish Soap||60.8g||1/4 cup|
|Rubbing Alcohol||51.3g||1/4 cup|
Now that we’ve calculated the densities of each substance, we are ready to make predictions about what order the liquids will settle in our density columns! Make a prediction about the order you think the liquids will settle based on your data. Order your list from liquid on the bottom to liquid on the top, and write down your prediction.
Add each liquid to a clear hollow cylinder, pouring the liquid you think will be on the bottom first, and continuing to layer according to your predictions. Within an hour, the liquids will all settle, and you should have something that looks like the picture at right.
As most of you probably predicted, the highest density liquids were at the bottom of the column, while the lowest rose to the top. The greater the mass per volume, the greater the effect of gravity on the liquid!
If you used our liquids, you should see this order, bottom to top: Corn Syrup, Dish Soap, Salt Water, Water, Vegetable Oil, Rubbing Alcohol, Baby Oil. Sometimes the Water and Salt Water will mix into one layer since they are close in density!