STEMonstrations: Properties of Water

Summary

In this video, astronaut Nicole Mann explores the fascinating properties of water, from its molecular structure to its essential role in life on Earth and in space. She explains water's polarity, its ability to dissolve various substances, and how it behaves differently in microgravity. Through engaging demonstrations, Mann highlights water’s unique cohesion and adhesion properties, showcasing its importance for both human biology and plant growth in space. Water’s vital role is emphasized, whether it’s supporting life on Earth or aiding astronauts aboard the International Space Station.

Takeaways

• 😀 Water makes up 60-75% of the human body and covers 71% of Earth's surface, highlighting its importance for life.
• 😀 Water is a polar molecule made of two hydrogen atoms and one oxygen atom, with unique properties due to its electronegativity difference.
• 😀 Water is the only substance that can exist as a solid, liquid, and gas under normal Earth conditions.
• 😀 Unlike most materials, ice is less dense than liquid water, allowing it to float on water due to its molecular structure.
• 😀 Water is a universal solvent, capable of dissolving more substances than any other liquid, which is crucial for biological processes.
• 😀 The human kidneys rely on water's solvent properties to filter waste and minerals from the body.
• 😀 In microgravity, traditional salt and pepper shakers are not usable, so water is used to create liquid salt, and oil is used to suspend pepper.
• 😀 Water’s properties of cohesion (molecules sticking together) and adhesion (molecules sticking to surfaces) play a significant role in microgravity.
• 😀 In microgravity, water does not drip from a towel when wrung out due to the combination of cohesion and adhesion.
• 😀 Plants use capillary action to move water and nutrients from roots to other parts of the plant, a process that relies on water’s adhesive and cohesive properties.
• 😀 The Veggie 05 experiment on the International Space Station is growing dwarf tomatoes, utilizing controlled conditions and water’s properties to nourish the plants.
• 😀 Water is essential in daily life, found in everything from food and drinks to household products, emphasizing its crucial role on Earth and in space.

Q & A

What percentage of the human body is made up of water?

The human body is made up of 60 to 75 percent water by weight.

What percentage of Earth's surface is covered by water?

Water covers roughly 71 percent of Earth's surface.

What is the chemical structure of water?

Water is composed of two hydrogen atoms and one oxygen atom, making it a polar molecule.

Why is water considered a polar molecule?

Water is considered a polar molecule because there is a difference in electronegativity between the oxygen and hydrogen atoms. This makes the oxygen atom negatively charged and the hydrogen atoms positively charged.

Why does ice float on water?

Ice floats on water because it is less dense than liquid water. This occurs due to the molecular structure of water and the way the molecules arrange themselves in solid form.

Why is water called a universal solvent?

Water is called a universal solvent because it can dissolve more substances than any other liquid, thanks to its polar nature and ability to break down many compounds.

How does water assist the kidneys in filtering waste?

Water helps the kidneys by dissolving minerals and waste materials, enabling the kidneys to filter and flush them out of the body effectively.

Why can’t astronauts use traditional salt and pepper shakers in space?

In microgravity, salt and pepper would not stick to food and would float away, potentially clogging air vents, contaminating equipment, and causing discomfort. Instead, astronauts use liquid salt and pepper for seasoning.

What is the role of adhesion and cohesion in water?

Adhesion is when water molecules stick to other surfaces, and cohesion is when water molecules stick to each other. These properties help water interact with surfaces and move through systems like plants.

How do plants move water and nutrients from their roots to other parts of the plant?

Plants use capillary action, which is driven by water's adhesion to plant tissues and cohesion between water molecules, to transport water and nutrients from the roots upwards.

What experiment is currently being conducted aboard the International Space Station related to plants?

The Veggie 05 experiment is growing dwarf tomatoes aboard the International Space Station. Astronauts use specialized habitats to control lighting and living conditions, and water is injected into a pillow at the base of the plant to sustain its growth.