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Science Launch G5 / Week 04 / Monday
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Week 04 · Something New

Monday

Mix and see
// Mixing can make a new substance
⏱ about 15 min

Monday: Mix and see

Rocket wants a rocket that launches itself, no buttons. He sketches a bottle with a fizzing engine.

"When baking soda and vinegar mix, they foam like crazy," he says. "That foam is my fuel."

Raven looks at the sketch. "Where does the foam come from?" she asks. "Neither one is foamy in its jar."

Nova projects two jars side by side. "Interesting," she says. "Is the foam one of the old substances, or something new?"

Rocket taps his pencil on the paper. "Something new," he whispers. "Maybe."

Mixing versus reacting

Sometimes mixing two substances just makes a mixture. Each substance stays itself.

Remember the salt from Week 1? It dissolved, and then came back as salt when the water evaporated.

Other times, the substances react. A chemical reaction makes a new substance with different properties.

A new substance

When baking soda and vinegar mix, they react and make carbon dioxide gas.

Carbon dioxide was not in either jar as a gas. It is a new substance formed by the reaction.

The bubbles you see are carbon dioxide escaping.

MIXTURE OR REACTION?
  • Read the question.
  • Tap your answer.
Salt dissolves in water and comes back as salt later. Is it a new substance?
Baking soda and vinegar make bubbles of a gas. What is the gas?
StatementTrue or false?
A chemical reaction forms a new substance.?
Every time you mix two things, a new substance forms.?
The bubbles from baking soda and vinegar are carbon dioxide.?
WHY THIS EXERCISESome mixing only makes mixtures, but reactions make new substances like carbon dioxide.
Big question for the week
How can we tell, using evidence, that a new substance formed?

Old substances, new substance

Before mixing, Rocket has two substances: baking soda and vinegar.

After mixing, there is something that was not there before: carbon dioxide gas.

A new substance with new properties is the sign of a chemical reaction.

NEW OR NOT?
  • Read the question.
  • Tap your answer.
Which change makes a new substance?
A substance is one kind of matter with its own what?
Where did Rocket's foam come from?
A change that forms new substances is a chemical ____.
The gas in baking soda and vinegar bubbles is carbon ____.
ROCKET'S FIZZ ENGINE
  • ?The two substances react.
  • ?Vinegar is poured in.
  • ?Baking soda sits in the bottle.
  • ?Bubbles foam up and escape.
  • ?Carbon dioxide gas forms.
WHY THIS EXERCISEReacting substances form a new gas that bubbles out.
Draw two boxes. In the first, show salt dissolving in water. In the second, show baking soda and vinegar fizzing. Label which one makes a new substance.
StatementTrue or false?
Carbon dioxide was in the vinegar jar as a gas before mixing.?
A mixture can keep each substance the same.?
Dissolved salt comes back as salt when the water evaporates.?
WHY THIS EXERCISECarbon dioxide forms in the reaction. Dissolving only makes a mixture.
What new gas forms when baking soda and vinegar react? Type two words.
WHY THIS EXERCISEThe reaction makes carbon dioxide.

Good thinking about invisible changes. Tomorrow we will learn the clues that show a reaction happened.