Ever wondered why lemons float and limes don't? Here's the fascinating answer

Lemon and lime experiment: Drop a lemon and a lime into a bowl of water, and you'll probably notice something unexpected. The lemon floats, while the lime often sinks. Considering how similar the two fruits look, it seems like they should behave the same way. But they don't, and the reason is surprisingly simple.

The experiment of lemons and limes in water

Curiosity to find the reason arose after someone noticed that lemon slices floated in a glass of infused water while lime slices settled lower.

To find out why, whole lemons and limes were tested in water. The experiment didn't stop there. The fruits were also peeled and sliced before being placed back into the water.


No matter how they were tested, the pattern remained the same. Lemons floated, while limes sank, as per a BestFoodFacts report.

An expert explains why lemons and limes behave differently

According to registered dietitian Sarah Downs, the explanation comes down to density, the relationship between an object's mass and its volume. Objects that are less dense than water float, while those that are denser sink.

Lemons and limes are both very close to the density of water, but limes are slightly denser. That tiny difference is enough to change what happens when they are placed in water.

Downs explained, “The reason limes sink and lemons float is due to density, or the mass per unit of volume. An object will float if it is less dense than the liquid it is placed in and will sink if it is denser than the liquid it is placed in. Lemons and limes both have densities that are very close to water, so you would expect that they would both float. However, limes are slightly denser than lemons, which is why they sink and lemons float,” as quoted by BestFoodFacts.

How researchers measured the density of lemons and limes

To understand the difference more closely, STEM educator and American TV personality Steve Spangler's team of lemon lime researchers compared a lemon and a lime that weighed exactly the same, 101 grams.

Although they had the same weight, they didn't have the same volume.

Using water displacement, they found that:

• The lemon had a volume of 99 milliliters.
• The lime had a volume of 90 milliliters.

Using these measurements, they calculated each fruit's density. The lemon's density was 1.02 grams per milliliter, while the lime's density was 1.12 grams per milliliter, as per the Stevespangler. com report. Since water has a density of about 1 gram per milliliter, the lemon remains buoyant, while the denser lime sinks.

What happens when you peel lemons and limes

At first, it seemed like the peel might explain everything. Lemon peels are thicker and contain more tiny air pockets than lime peels, similar to oranges, which are known to float because of their porous rind.

But when both fruits were peeled and tested again, the lemons still floated and the limes still sank. That showed the peel wasn't the main reason behind the difference.

Because lemons, limes and water all have very similar densities, even a small variation in their internal structure can change whether they float or sink.

FAQs

Why do lemons float in water?
Lemons are slightly less dense than limes, which helps them stay buoyant in water.

Does the peel make lemons float?
No. Even after peeling, lemons continued to float while limes still sank.