Cool Science Experiments With Water

Here are some cool science experiments using water that are safe to be performed at home.

The Water Cycle

Water is the most important element on Earth as all living beings need water to survive. Almost 75 percent of Earth’s surface is covered with water in the form of rivers, lakes, seas, and oceans.

Main sources of water

• Rainwater – During rainy season, rainwater seeps through the soil and is stored in the underground table. This water is used by digging wells.
• Surface water – This includes different water bodies like reservoirs, rivers, streams, ponds, and lakes.
• Groundwater – this includes water bodies like wells and springs.
• Manmade sources: Bore wells, dams, canals, an tans are manmade sources of water.

Water from rivers, dams, lakes, etc. is passed to the purification plants through closed pipelines. Water is filtered here. From the purification plants, water is distributed o the houses through the network of pipes. Once it reaches our house, we store it in tanks and containers, like bottles, pots, buckets, etc.

The Water Cycle

Earth has been recycling water for over 4 billion years.

Water from the various water bodies on Earth evaporates because of the Sun’s heat (Evaporation). The water in the form of vapour then cools down at certain height and condenses to form clouds (Condensation). When too much water gets collected, the clouds become heavy and the water falls from the sky in the form of rain, snow or hail (Precipitation). The water gets collected in oceans, lakes, or ponds (Collection).

This water again gets evaporated starting the whole water cycle again.

Experiment

You can easily carry out an experiment at home to demonstrate the water cycle. You need common household items such as a large bowl, a smaller bowl/cup, a plastic wrap, water, ice cubes, a lamp (or a sunny spot).

Steps: You first need to fill the large bowl with about 2 inches of water. Place the small cup in center of the large bowl. Stretch the plastic wrap over the large bowl (it should be tightly sealed around the edges). Place some ice cubes on top of the plastic wrap, directly above the smaller cup. Place the setup in a sunny spot or under a lamp (that is powerful enough to generate heat). Leave the setup for a few hours.

Observation: The heat from the lamp will cause the water in the large bowl to evaporate. The water vapor will rise and hit the plastic cling wrap, where it cools down (condenses) due to the ice cubes and forms droplets. The droplets will gather and precipitate (drip down like rain) into the smaller bowl or cup. The collection of the water happens in the smaller bowl.

You can also demonstrate this concept by using a kettle to heat water (an adult should do this experiment as kids should not be using a kettle).

Just hold a plate with ice cubes against the spout of kettle and place an empty bowl beneath this plate to collect the water droplets.

• The Great Big Water Cycle Adventure (Book): Fun book for kids (Kindergarten to third grade students) about the water cycle

Cloud in a Jar

We see clouds forming in the sky due to the heat in the atmosphere. You can also make a fluffy cloud in a jar and learn the science behind it.

Materials: Glass jar with a lid, 1 cup hot boiling water, blue food color (optional), Aerosol hairspray, 3-5 cubes of ice.

Note: An adult need to demonstrate this experiment (due to use of boiling water).

Steps:

• Take 1 cup boiling water. Add food coloring to make the water blue. It will help distinguish the cloud from the water and make it look like the sky.
• Pour the cup of hot boiling water into a glass jar.
• Quickly spray hairspray into the jar.
• Immediately put the lid onto the jar.
• Place 3-5 pieces of ice on top of the lid of the jar.

Observation: In sometime, you will see a cloud beginning to form in the jar, collecting below the lid. As you open the lid, you can see the cloud move out of the jar and into the air.

The warm water in the jar causes some of the water to evaporate into the air. The water vapors then rise from the surface of the water to the top of the jar.

Once it reached the top of the jar, the warm, moist air began to cool down. This is because of the ice that was on the lid of the jar.

This cooling causes the water to condense onto the particles of hairspray, forming a cloud in the jar.

Density and Buoyancy Experiment

this experiment teaches concepts such as Density, buoyancy, Archimedes’ principle.

You need materials such as coins (or stones), water, various liquids (e.g., oil, syrup).

The experiment involves dropping coins into different liquids and observing whether they float or sink.

• Explanation: This illustrates how the density of an object relative to the liquid determines whether it will float or sink.

Surface Tension Experiment

This science experiment teaches concepts such as surface tension, cohesion.

You need materials such as coins, water, dropper.

• Procedure: Use a dropper to carefully place water droplets on the surface of a coin and count how many drops fit before the water spills over.
• Explanation: This demonstrates surface tension and the cohesive forces between water molecules.