Short Answer

Small insects can walk on water because of the high surface tension of water. Surface tension makes the surface of water behave like a thin, stretchy skin. This strong, tight surface supports the light body weight of insects without breaking.

These insects also have long legs and water-repellent (hydrophobic) hairs that help them stay on top of the water. Their legs spread their weight over a larger area, preventing them from sinking. Because of these features and water’s strong surface tension, small insects can easily walk on water.

Detailed Explanation :

Small insects walk on water

Many small insects, such as water striders, pond skaters, and tiny bugs, can walk or glide on the surface of water. This special ability comes from surface tension, which allows the water’s surface to resist external force and act like a tight, flexible skin. Water has very strong intermolecular forces, especially hydrogen bonding, that create high surface tension. Combined with the insects’ special body structure, this helps them stay on top of the water without sinking.

Water molecules attract each other strongly. These forces pull the molecules at the surface tightly together, making the surface strong enough to support light objects. Small insects weigh very little and their legs are adapted to spread their weight, allowing them to stay on the surface.

1. High surface tension of water

Surface tension is the main reason insects can walk on water. Water has strong hydrogen bonds that pull its surface molecules together. This creates a tight surface that can hold light objects.

For insects:

• Their bodies are extremely light
• Their legs do not break the surface tension
• The water surface acts like a stretchable sheet

Because of this, the insects remain on the surface instead of sinking beneath it.

2. Weight of insects is very small

Small insects are very lightweight. Their mass is so low that they do not create enough downward force to break the water’s surface. Since surface tension is strong enough to hold their weight, insects stay on the surface.

If a heavier object is placed on the water, it sinks because its weight is greater than the force created by surface tension. But insects are light enough to be supported.

3. Long, thin legs increase surface area

Insects that walk on water have long, thin legs that spread their body weight over a large area. When weight is spread out, pressure decreases. This allows the insect to stay on top of the water.

This is similar to:

• Lying flat on thin ice instead of standing
• A person wearing snowshoes not sinking into snow

The large contact area reduces pressure and prevents them from breaking the surface.

4. Water-repellent (hydrophobic) legs

The legs of water-walking insects are covered with tiny hairs that trap air. These hairs make the legs water-repellent or hydrophobic. Because of this:

• Water does not stick to their legs
• Their legs do not get wet
• They do not sink

The trapped air also gives extra buoyancy, helping them float easily.

5. Adaptation for movement

Insects like water striders have special adaptations that help them move smoothly:

• Their middle legs push the water
• Their hind legs act like steering tools
• Their front legs help catch prey
  These adaptations, along with surface tension, let them glide rapidly across the water.

6. Surface tension acts like a flexible skin

Because surface tension makes water behave like a thin sheet, insects can press against it without breaking it. The surface bends slightly under their legs but does not tear.

This is why you often see tiny dents or ripples where insects step. As long as the surface tension remains unbroken, the insect stays afloat.

7. Why larger animals cannot walk on water

Larger animals cannot walk on water because:

• Their weight is too high
• Their feet do not spread weight enough
• They break the surface tension instantly
  Thus, surface tension can only support small, lightweight creatures.

8. Real-life examples

Some insects that walk on water include:

• Water striders
• Pond skaters
• Jesus bugs
• Water boatmen (move on water surface)

These insects use surface tension to move, rest, hunt, or escape predators.

Conclusion

Small insects walk on water mainly because water has high surface tension, which creates a strong, flexible surface capable of supporting their lightweight bodies. Their long, thin, water-repellent legs help spread their weight and prevent them from sinking. These adaptations, combined with water’s unique properties, allow insects to glide, skip, and walk across water with ease.