Properties of Water Amoeba Sisters Video Handout - Science is Real ... - Free Printable

The image you've uploaded is a "Properties of Water" video handout designed to accompany the Amoeba Sisters' YouTube video on water properties. It's an educational worksheet with sections for pre-video questions, showtime questions, a crossword puzzle, and extension activities.

Below is a complete solution and explanation for all parts of the worksheet based on scientific knowledge about water:

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## ✔ BEFORE THE SHOW
> What do you think happens to fish and other aquatic organisms when a lake freezes over in the winter?

✔ Answer:

When a lake freezes over in winter, the ice forms on the surface, which acts as an insulating layer. This keeps the water below from freezing completely, allowing fish and other aquatic organisms to survive in the liquid water beneath. The fact that ice is less dense than liquid water (due to hydrogen bonding) allows it to float, protecting life underneath.

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## ✔ SHOWTIME QUESTIONS

1. Which of the following is NOT true of water?

- a. Life could not survive without water. → True
- b. It makes up about ¾ of the surface of Earth. → True
- c. It contains one hydrogen and two oxygen atoms. → ✘ False

> ✔ Correct answer: c
> Water has two hydrogen atoms and one oxygen atom (H₂O). So this statement is incorrect.

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2. Why is water a polar molecule?

- a. Oxygen has a negative charge, and hydrogen has a positive charge. → ✔ Correct
- b. Oxygen has a positive charge, and hydrogen has a negative charge. → ✘
- c. Oxygen and hydrogen both have a positive charge. → ✘

> ✔ Answer: a
> Oxygen is more electronegative than hydrogen, so it pulls electrons closer, giving it a partial negative charge (δ⁻), while hydrogens become partially positive (δ⁺).

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3. What type of chemical bond gives water its exceptional properties?

- a. covalent bond → Forms the molecule, but not responsible for unique properties
- b. ionic bond → Not present in water
- c. hydrogen bond → ✔ Correct

> ✔ Answer: c
> Hydrogen bonds between water molecules are responsible for high boiling point, surface tension, cohesion, adhesion, etc.

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4. Which property of water allows molecules to stick to another surface (such as xylem)?

- a. adhesion → ✔ Correct
- b. cohesion → Sticking to same substance
- c. polarity → General characteristic

> ✔ Answer: a
> Adhesion is the attraction between different substances (e.g., water and plant cell walls).

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5. Which property of water makes it possible for water striders to skate above the water?

- a. adhesion → No
- b. cohesion → Partially related, but not directly
- c. density → No

> ✔ Answer: b – Actually, cohesion contributes to surface tension, which supports water striders.

But wait — let’s clarify:

> 🟨 Best answer: Surface tension — but not listed directly. However, cohesion causes surface tension.

So among choices:
✔ Answer: b. cohesion
Because cohesion creates strong intermolecular forces at the surface, leading to surface tension, enabling water striders to walk on water.

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6. Which property describes a liquid's ability to resist external force?

- a. cohesion → Sticking together
- b. polarity → Charge distribution
- c. surface tension → ✔ Correct

> ✔ Answer: c
> Surface tension is the resistance of a liquid surface to external forces due to cohesive forces.

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7. What two types of compounds is water especially good at dissolving?

- a. covalent and polar compounds → ✘
- b. ionic and polar compounds → ✔ Correct
- c. ionic and nonpolar compound → ✘

> ✔ Answer: b
> Water is a universal solvent because it dissolves ionic compounds (via ion-dipole interactions) and polar molecules.

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8. In which state of matter is water least dense?

- a. solid → ✔ Correct
- b. liquid
- c. it is the same density in all states

> ✔ Answer: a
> Ice (solid water) is less dense than liquid water, so it floats.

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9. What is the measurement of heat that needs to be absorbed or lost for 1 gram of a substance to change temperature by 1°C?

- a. specific polarity → ✘
- b. specific heat → ✔ Correct
- c. stabilizing heat → ✘

> ✔ Answer: b
> Specific heat capacity measures how much energy is needed to raise 1g of a substance by 1°C.

Water has a high specific heat (~4.18 J/g°C), meaning it resists temperature changes.

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10. Why is water resistant to changing temperatures?

- a. neutral specific heat → ✘
- b. low specific heat → ✘
- c. high specific heat → ✔ Correct

> ✔ Answer: c
> Because of its high specific heat, water absorbs or releases large amounts of heat with minimal temperature change.

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11. How does the specific heat of water affect the environment?

- a. warms climate → Not directly
- b. stabilizes temperatures → ✔ Correct
- c. triggers ecological succession → Not relevant

> ✔ Answer: b
> Oceans and lakes moderate climate by absorbing heat during day/summer and releasing it slowly, preventing extreme temperature swings.

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12. What do animals and plants rely upon to cool them down in warm temperatures?

- a. evaporative cooling → ✔ Correct
- b. condensational cooling → ✘
- c. cellular winds → ✘

> ✔ Answer: a
> Evaporation of sweat (animals) or transpiration (plants) removes heat from the body, cooling it.

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## ✔ AFTER THE SHOW – Part A: Crossword Puzzle

Let’s solve the clues.

Across:

3. Molecule that contains 2 hydrogen and 1 oxygen atom → Water
6. Least dense state of matter in water → Solid
7. Measurement of heat... → Specific heat
10. Atom in water with slightly positive charge → Hydrogen

Down:

1. Type of bond between water molecules → Hydrogen bond
2. Property describing a liquid's ability to resist external force → Surface tension
4. Ability of water to stick to other water molecules → Cohesion
5. Ability of water to stick to another substance → Adhesion
8. Atom in water with slightly negative charge → Oxygen
9. Type of molecule with unequal sharing of electrons → Polar

Now fill in the crossword:

```
1 H Y D R O G E N B O N D
2 S U R F A C E T E N S I O N
3 W A T E R
4 C O H E S I O N
5 A D H E S I O N
6 S O L I D
7 S P E C I F I C H E A T
8 O X Y G E N
9 P O L A R
10 H Y D R O G E N
```

(You can sketch this out based on intersections.)

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## ✔ Part B: Label the Water Molecule Diagram

Label these on the diagram:
- Hydrogen atoms: Small green spheres (usually)
- Oxygen atoms: Larger purple sphere
- Charges:
- Oxygen: δ⁻ (partial negative)
- Hydrogen: δ⁺ (partial positive)
- Hydrogen bond: Dashed line between H of one molecule and O of another

> 💡 Tip: The dotted line between molecules represents a hydrogen bond.

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## ✔ EXTENSION: Research Water Striders

1. Describe how water striders are able to walk on water.

> Water striders walk on water due to surface tension created by cohesive forces between water molecules. Their legs are long and thin, distributing weight, and covered in water-repellent hairs that prevent sinking.

2. What adaptations do water striders have?

- Long, slender legs to distribute weight
- Hydrophobic (water-repellent) leg hairs to stay dry
- Lightweight bodies to reduce pressure on water surface
- Sensory hairs to detect ripples from prey

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## ✔ Summary of Answers

| Question | Answer |
|--------|--------|
| 1 | c |
| 2 | a |
| 3 | c |
| 4 | a |
| 5 | b |
| 6 | c |
| 7 | b |
| 8 | a |
| 9 | b |
| 10 | c |
| 11 | b |
| 12 | a |

Crossword Clues:

- Across: 3=Water, 6=Solid, 7=Specific heat, 10=Hydrogen
- Down: 1=Hydrogen bond, 2=Surface tension, 4=Cohesion, 5=Adhesion, 8=Oxygen, 9=Polar

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## ✔ Final Notes

This handout teaches key concepts:
- Polarity of water
- Hydrogen bonding
- Cohesion & Adhesion
- Surface tension
- High specific heat
- Density anomaly (ice floats)

These properties make water essential for life!

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✔ Bonus Features Mentioned in Image:
- 2-page PDF version
- Google Slides version
- Answer key included

Let me know if you'd like a printable version or editable Google Slides file!