STEMonstrations: Properties of Water

TL;DR

Water, a polar molecule, exhibits unique properties such as being a universal solvent, having a solid form less dense than its liquid form, and demonstrating adhesion and cohesion.

Transcript

foreign hello my name is Nicole Mann and I'm an astronaut  living and working aboard the International Space   Station did you know that our bodies are  made up of 60 to 75 percent water in weight   and water covers roughly 71 percent of Earth's  surface have you ever wondered what it is about   water that makes it so important for life well  today... Read More

Key Insights

• 💦 Water is a polar molecule due to the difference in electronegativity between its atoms.
• 💁 The molecular structure of water causes its solid form to be less dense than its liquid form.
• 🚰 Water acts as a universal solvent, being able to dissolve more substances than any other liquid.
• 🤽 Adhesion and cohesion, properties of water, play a role in various phenomena such as capillary action and the sticking of water to surfaces.
• 👨‍🚀 Water is essential for bodily functions and is used by astronauts in space for various purposes.
• 👾 Water's unique properties are vital for life on Earth and in space.
• 💦 Microgravity affects the behavior of water, causing it to not adhere to surfaces in the same way as on Earth.

Questions & Answers

Q: Why is water referred to as a polar molecule?

Water is referred to as a polar molecule because it has a difference in electronegativity between its oxygen and hydrogen atoms. This causes the oxygen atom to be electronegative and the hydrogen atoms to have a positive charge.

Q: What makes ice less dense than liquid water?

The molecular structure of water causes its solid form (ice) to have a lower density than its liquid form. This is due to hydrogen bonds that expand the crystal structure of ice, making it less dense.

Q: Why is water called a universal solvent?

Water is called a universal solvent because it can dissolve more substances than any other liquid. This is due to its ability to form hydrogen bonds with other molecules, allowing it to break them apart and dissolve them.

Q: How do astronauts use water's properties in space?

In microgravity, astronauts use water's properties of adhesion and cohesion to create liquid forms of salt and pepper, as salt easily dissolves in water and pepper is suspended in oil. Water is also utilized for various functions on the International Space Station, such as growing plants.

Summary & Key Takeaways

• Water is a polar molecule composed of two hydrogen atoms and one oxygen atom, giving it unique properties.

• Unlike most materials, the solid form of water (ice) is less dense than its liquid form, causing it to float on water.

• Water is a universal solvent, meaning it can dissolve more substances than any other liquid, and is vital for many bodily functions.