ShareEarth's Structure - Help I'm Drowing
Water has a density of 1.0 g/cm3 (one gram per cubic centimeter). Objects that have a density greater than 1.0 g/cm3 will sink in water. Objects that have a density less than 1.0 g/cm3 will float in water. When you fill a graduated cylinder with water, there is often a curve instead of straight line at the top of the cylinder. This curve is known as a "meniscus."
Your challenge in this activity will be to accurately measure both mass and volume. Using this data, you will calculate density.
The formula for calculating density is: 
.
Materials:
- Balance scale
- Calculator
- graduated cylinder (large enough for objects to fit into)
- Pencil or pen
- Paper
- Water
- Variety of items with different densities
Safety concerns: 
Be sure to follow all chemical and glassware object safety
rules that are specified by your teacher in all general laboratory
experiences.
Procedures:
- Select one item and predict whether it will sink or float in water.
- Record your prediction.
- Using the same item, determine its volume by using a graduated cylinder and water.
- Fill the cylinder to a designated amount and record this starting point.
- Gently drop in the item. Record the amount of water that was displaced by the item.
- If the graduated cylinder is not large enough for the selected item, set a small container in an empty larger pan.
- Completely fill the small container with water.
- Gently drop the item into the water.
- Water will spill out into the larger container.
- Measure this water as the amount that is displaced = volume.
- Using same item, determine its mass by weighing the item on balance scale. Record the mass.
- Divide the mass by the volume to calculate the density and record the item's density.
- Items having a density greater than1.0 g/cm3 will sink; items having a density less than 1.0 g/cm3 will float.
- Organize items you tested into appropriate groups based on whether they sink or float.
Analysis:
- How well did you predict which objects would float and which would sink in water?
- What other items would you like to test to determine their density?
- Get permission and try your other objects and calcuate their density.
Extension:
Try to find an object that has a density which is greater than 1.0 g/cm3 but will still float in water!
