Convection Experiment (Video)

Water is a vital element in our lives. Its properties and behavior have always intrigued scientists, educators, and students alike.

One fascinating aspect of water is how it moves in response to differences in temperature, creating convection currents.

Understanding these currents is essential in explaining various natural phenomena, such as the formation of thunderstorms, deep-sea currents, and even wind patterns.

Convection currents can be observed in the oceans, where varying temperature and salinity levels give rise to deep-sea currents.

Ocean currents are like a moving belt in the ocean. These currents transport warm water and precipitation from the central regions of the Earth towards the upper parts while simultaneously moving cold water from the upper back towards the middle.

This helps in redistributing heat around the planet.

By doing so, ocean currents help control the world’s climate by balancing the differences in sunlight across the planet.

It helps to maintain global climatic balance and contributes to the ocean’s biodiversity.

Convection currents also exist in the atmosphere, where the rising of warm air and the sinking of cooler air creates wind patterns and weather systems, such as thunderstorms.

What is a thunderstorm?

A thunderstorm refers to a weather phenomenon characterized by the presence of both lightning and thunder.

Lightning occurs due to the buildup of electrical charges within the storm cloud, with negatively charged particles accumulating near the bottom and positively charged particles near the top.

The discharge of this electrical energy creates bright flashes of lightning and the subsequent sound waves we perceive as thunder.

Causes of thunderstorm

A thunderstorm results from the rapid updraft of warm, humid air, which collides with colder air in the upper atmosphere.

This process leads to the condensation of water vapor, followed by the formation of clouds and precipitation.

As the warm air rises, it loses heat and starts to cool, becoming denser and sinking back to the surface.

This continuous exchange of heat and the movement of air molecules due to convection currents result in the development of a thunderstorm.

Experiment, please?


The primary aim of this experiment is to showcase the formation of convection currents in water due to die temperature differences.

This exciting science experiment will explore the principles behind the water movement due to convection currents and how temperature felt the behavior of liquids.

This simple experiment is designed for both children and adults. It uses easily accessible and cost-effective materials, such as cups of water, food coloring, and a clear container, to illustrate the transfer of heat and the dynamics of water movement.

Here is an experiment to illustrate how thunderstorms formed using water.

Thunderstorm Science | Weather experiment

Thunderstorm Convection Experiment

Prep Time: 1 hour
Active Time: 30 minutes
Total Time: 1 hour 30 minutes

In this experiment, we need cold water with one coloring added to it and warm water with another so that we can see and distinguish the two. I used blue for the cold water and red for the warm.


  • washable paint or food coloring (2 different colors. I used blue for cold and red for warm.)
  • 2 cups
  • water


  • a large glass or clear plastic tank/container such as this (rectangular shaped preferred)
  • refrigerator
  • adult supervision


    1. To get cold water, you can first add the blue coloring into tap water and then chill it in the refrigerator. Or you can make ice cubes by putting it into the freezer.
    2. For the warm water, I used the microwave. After adding the red coloring into the warm water, you can either use a cup to hold it, or put it into a narrow-necked bottle.
    3. Fill the large tank with room temperature water.
    4. Slowly pour the cold water (or ice cubes) into one end of the tank.
    5. Then pour the warm water into the other end. If you use a bottle, simply place it into the water. Depending on the weight of the bottle and how much air is left in it, the bottle may sink or it may float. Both are fine.
    6. Observe how the blue quickly descends into the bottom of the tank while the red floats on top and the water churns. convection: red water floats from bottom to top, blue water sinks from top to bottom

Did you try this project?

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Cold water is denser than warm water, as the molecules are more tightly packed. Thus, when the water is mixed, cold water will sink while warm water rises to the surface. The motion is caused by variations in density caused by changes in temperature.

When cold and warm water are poured into a container, they create convection currents as they mix.

The colored water used in this experiment allows for better visualization of the movement of water through the convection process.

The cold water, represented by blue food coloring, sinks to the bottom of the container because of its higher density. On the other hand, the warm water, the red food coloring, rises to the surface due to its lower density.

The heat transfer between the cold and warm water causes the water molecules to expand or contract, further influencing the convection currents.

As the cold water warms, it becomes less dense and starts to rise. Then, the warm water cools, leading to an increase in density and a downward movement.

This continuous exchange of heat generates the convection currents observed in the experiment, with the colored water providing a visible demonstration of temperature-driven water movement.

It is because low-density fluid rises above the high-density one.

This process is called convection.

In the ocean (giant water tank), when water from areas with different temperatures comes together, convection makes the water churn to create a deep sea current.

Likewise, in the atmosphere, warm air rises. Then, the cold air falls to churn the air.

To create a thunderstorm, the air must be humid to form clouds and rain. Thus, thunderstorms often happen in the afternoon because the sun heats the air near the ground. When the air becomes unstable, pockets of warm air rise, making clouds, rain, and eventually lightning.

Want to learn more about water? Here are some science project ideas with water.

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