Physical Science
The Physical Science domain of the Grade 5 MCAS STE test asks you to use the particle model of matter, apply conservation of matter, identify materials by properties, explain gravity and motion, and trace energy. Questions often use measurements, mixtures, or simple force scenarios.
Matter and its properties
- All matter is made of particles too small to see. Particles are closely packed and vibrate in solids, slide past each other in liquids, and are far apart and move fast in gases.
- Properties such as hardness, conductivity, solubility, magnetism, density, and melting point help identify materials.
- In a closed system, mass is conserved during any change. In an open system, a gas may escape and the measured mass may drop.
- Mixtures can be separated by physical methods such as filtering, evaporating, or using a magnet.
Forces and motion
- Gravity is a force that pulls objects toward Earth's center. It acts without touching.
- A force can change an object's speed or direction. Balanced forces do not change motion.
- Without air resistance, objects fall at the same rate regardless of mass.
Energy and light
- Energy can be transferred or converted among forms: motion, light, sound, heat, and electric energy.
- Food energy traces back to the Sun through plants.
- Light travels in straight lines, reflects from surfaces, and enters your eyes so you see objects.
Worked example
A student mixes 50 g of vinegar with 5 g of baking soda in an open cup. After fizzing stops, the total mass is 53 g. Explain. The reaction produces carbon dioxide gas, which escapes into the air. Matter is not destroyed. If the cup were sealed, the total mass would remain 55 g.
Traps that cost marks
- Saying matter disappears during a reaction.
- Treating a gas as having no mass.
- Claiming heavier objects always fall faster.
- Calling a mixture a chemical change.