Year 8 Science · Unit 3 · Lesson 8
Foundation Worksheet
Learning Goals
True or False? Fix the false ones
Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.
When wood burns in an open fireplace, the mass of the ash is less than the original wood, proving that mass was permanently lost.
Correct it:
In a sealed flask, the total mass of substances before a reaction equals the total mass after the reaction.
Correct it:
Lavoisier's experiments in the 1780s proved that mass can be created by heating metals.
Correct it:
Gases have mass, even though they are invisible and spread out into the surroundings.
Correct it:
Odd one out
Circle the item that does not belong in each group. Then explain why it doesn't fit.
| # | Group | Your answer (odd one + reason) |
|---|---|---|
| 1 | Sealed flask Closed test tube Sealed reaction bag Open campfire | |
| 2 | Carbon dioxide gas Water vapour Ash residue Light energy | |
| 3 | Atoms rearranged Mass conserved New substances formed Atoms destroyed |
1. A student mixes vinegar and bicarbonate of soda in an open bowl. The mixture fizzes vigorously and when it stops, the bowl weighs less than before. Explain what happened to the mass, using the ideas of open systems and gas production.
2. In your own words, state the law of conservation of mass. Then explain how the particle model (atoms) supports this law.
Wrap Up
In one sentence, what was the main idea of this lesson?