Review

Review some of the important ideas about ice, water, and particles.

• When a container of water freezes, or a container of ice melts, the weight remains the same.
• We use weight to measure and track the amount of matter.
• When water freezes, its volume increases.
• When ice melts, its volume decreases.
• When water freezes or ice melts, the properties change but the material does not.
• Ice and water are different states of the same material.
• Condensation forms from water vapor in the air.
• Condensation is the reverse of the process of evaporation.
• Scientists believe all matter is made of particles too small to see.
• In ice, particles are locked together, even when they vibrate, and hold their shape.
• In water, particles slide past and collide with one another, and take the shape of its container.

Ask students if they would like to make any additions or changes.

Launch the new strand

Explain that students are about to spend four science classes investigating air. When particles are clumped together, we can see the matter and use our classroom tools to measure the weight and volume. When the tiny particles are spread apart, we cannot see them. Water vapor is an example of a material whose tiny particles are spread apart so we can't see them. Air is another example. Air is actually a mixture and water vapor is part of air.

Today's investigation question is:

Is air matter?

Students have measured the weight and volume of both solid and liquid materials, and have established they are matter. Today students use some new tools as they look for evidence to determine whether or not air is matter.