Water drops stay together on wax paper and don’t break apart easily. This is mainly because:

• Water molecules are small
• Water molecules are in motion
• Water molecules are attracted to each other
• Water molecules are wet

When you bring two drops of water near each other and allow them to touch, they combine immediately and become one drop. This is mainly because:

• Water molecules are made of atoms
• Water molecules are attracted to each other
• Water molecules are magnetic
• Water is a liquid

If you put food coloring in room temperature water, the coloring spreads throughout the water. The water causes the color to spread mainly because:

• Water molecules are warm
• Water molecules are in motion
• Water is more dense than food coloring
• Food coloring molecules are small

Food coloring spreads out faster in hot water than in cold water. This is mainly because:

• The water molecules in hot water move more quickly
• The molecules in hot water are larger
• The food coloring molecules are small
• Hot water is less dense

When a thermometer is heated, the red liquid inside the thermometer moves up. This is mainly because:

• The red liquid is thin
• The molecules of the liquid move faster and get a little further apart
• Hot liquid is lighter
• The glass of the thermometer gets hot

When a thermometer is cooled, the red liquid inside the thermometer moves down. This is mainly because:

• Cold liquids sink
• The glass of the thermometer gets cold
• The molecules of the liquid move slower and get a little closer together
• The red liquid is thick

To describe a liquid, you could say:

• The particles of a liquid are attracted to one another but don't move
• The particles of a liquid vibrate, are able to move past one another, and are attracted to one another
• The particles of a liquid are not attracted to one another and are very far apart from each other
• The particles of a liquid vibrate but don't move past one another

The molecules of the liquid inside the thermometer increase in speed when the thermometer is _______ .

• heated
• cooled
• turned upside down
• frozen

What happens when a liquid is heated?

• the particles of the liquid get bigger
• the particles get closer together
• the total number of particles increases
• the space between the particles increases

What happens to the kinetic energy of liquid particles when cooled?

• the average kinetic energy increases
• the average kinetic energy decreases
• the average kinetic energy stays the same
• the kinetic energy changes into chemical energy