Grade Level: Kindergarten to 5th; Type: Physical Science
Demonstrate the correspondence between the volume of water displaced by an object and and the volume of the object displacing it.
- What happens when you drop an object into a glass of water?
- What happens when you drop a larger object into a glass of water?
- How many of each object can you drop into the glass of water before it overflows?
- Can you predict how many of each object it will take to make a different glass of water overflow?
Archimedes, upon stepping naked into his bath, famously cried out “Eureka!” when he suddenly understood the correspondence between the volume of water displaced by a submerged object and the volume of the object displacing it. This project demonstrates this displacement of water and the correspondence of volumes, and exercises prediction skills.
- Two glasses of the same size and shape
- Glasses of other sizes and shapes
- A wax pencil to mark the glasses
- A bunch of pennies
- A bunch of small rocks, approximately the same size as each other but bigger than a penny
- Other sinking objects
- A tray to control spills
- Fill two glasses partway, each with the same amount of water.
- Mark the water level on the glasses.
- Drop a penny into the first glass. What happens to the water?
- Drop a rock into the second glass. What happens to the water?
- Drop 10 pennies into the first glass. What happens to the water?
- Drop 10 rocks into the second glass. What happens to the water?
- Keep dropping pennies and rocks into their respective glasses until the water overflows. How many pennies does it take to make the water overflow? How many rocks?
- Fill a different glass partway with water.
- Predict how many pennies it will take to make that glass overflow. Predict how many rocks it will take. Test your predictions.
- Try this with many different sizes and shapes of glasses and many different (sinking) objects.
- Predict how many Object A’s it will take to make the water level rise the same amount as Object B. How do the volumes of Object A and Object B compare to each other?
Terms/Concepts: displacement, volume, compare, predict