A lemon floats in salty water because the density of the saltwater is greater than the density of the lemon.
Understanding Density and Buoyancy
The ability of an object to float or sink in a liquid depends on the relationship between the object's density and the liquid's density. Density is the mass per unit volume of a substance. Buoyancy is the upward force exerted by a fluid that opposes the weight of an immersed object. If an object is less dense than the liquid, it will float. If it is more dense, it will sink.
Why Saltwater Makes a Difference
Plain water has a certain density. When salt is added, the salt molecules occupy spaces between the water molecules, effectively packing more mass into the same volume. This increases the density of the water. According to the provided reference, a lemon sinks in normal water but floats in salty water because the density of saltwater is more than in normal water.
Lemon's Density vs. Water Density
- Freshwater: The density of a lemon is slightly higher than that of freshwater, causing it to sink.
- Saltwater: The density of saltwater is higher than the density of the lemon, causing it to float.
Practical Demonstration
Here's a simple experiment you can try:
- Fill two glasses with water.
- Add a few tablespoons of salt to one glass and stir until dissolved.
- Place a lemon in each glass.
- Observe that the lemon sinks in the plain water but floats in the saltwater.
Summary Table
| Liquid | Density | Lemon Behavior | Explanation |
|---|---|---|---|
| Freshwater | Lower | Sinks | Lemon's density is higher than freshwater's density. |
| Saltwater | Higher | Floats | Saltwater's density is higher than the lemon's density. |
