Exploring the Science Behind Hand Warmers

What is inside the hand warmer that dissolves in water?

• Potassium nitrate

• Sodium acetate

• Calcium chloride

• Sodium chloride

What is the maximum temperature the hand warmer can reach?

• 50 degrees Celsius

• 40 degrees Celsius

• 30 degrees Celsius

• 60 degrees Celsius

Tags

NGSS.MS-PS1-4

What triggers the hand warmer to start producing heat?

• Clicking a metal disc inside

• Exposing it to sunlight

• Placing it in the freezer

• Shaking it vigorously

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3

What is the role of the metal clicker inside the hand warmer?

• To measure temperature

• To start the crystallization process

• To keep the solution mixed

• To prevent overheating

Why does the water get cold when sodium acetate crystals are added?

• The reaction is endothermic

• The water evaporates

• Thermal energy is used to separate ions

• The crystals absorb heat

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is the primary component that needs to be dissolved in water to make the hand warmer work?

• Sodium bicarbonate

• Potassium chloride

• Sodium acetate

• Magnesium sulfate

What is necessary for crystals to form in the hand warmer solution?

• A tiny particle or nucleus

• Vibration or movement

• A magnetic field

• A high temperature

Why does the hand warmer stay liquid after being cooled down if properly reset?

• Because of the pressure inside

• Due to the absence of nucleation sites

• Because it's a permanent chemical change

• Due to the addition of stabilizers

Tags

NGSS.MS-PS1-4

How can you reuse the hand warmer?

• Freeze it for an hour

• Heat it in boiling water

• Leave it in sunlight

• Shake it for a few minutes

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3

What happens if the hand warmer is not heated long enough during reuse?

• It will not produce heat

• It may spontaneously activate

• It loses its color

• It becomes permanently solid

Tags

NGSS.MS-PS3-3