Science · Grade 5 Science
Chapter 1: Matter and Its Properties
Too small to see is not the same as not there.
Watch first. The explanation comes later.
Stir sugar into water and it vanishes completely. The water is perfectly clear. It is also unmistakably sweet.
Where did the sugar go?
Step through each change and count the dots each time.
Step 1 — Predict
Sugar dissolves into water. How many particles are left in the jar?
Choose what you think will happen. You cannot see the experiment until you do — guessing first is what makes it worth watching.
Now the explanation, after you have seen it happen.
Everything is made of particles far too small to see, with space between them. This one idea explains a great deal at once: why a solid holds its shape, why a liquid pours, why a gas fills a room, and why sugar can vanish into water without ceasing to exist.
Particle A tiny piece of matter, too small to see.
In a solid they are packed and locked. In a liquid they are loose. In a gas they spread out through the whole space.
Melting, dissolving and boiling rearrange the particles. None of them makes any disappear.
You cannot see dissolved sugar. You can taste it, and you can weigh it.
Air has mass, takes up space and can be compressed. You cannot see it, and a balloon proves it is there. Much of chemistry rests on accepting evidence about things too small to observe directly.
Smells spread across a room, sugar disappears into water without raising the level much, and gases can be squashed. All three make sense if matter is made of tiny separated pieces.
Lots of people think
“When sugar dissolves it disappears. It has turned into water.”
The same idea somewhere new.
A single drop of water contains roughly a thousand billion billion molecules. If you could line up a million of them side by side, the row would be about as thick as a human hair. That is why you cannot see them, and it is not a reason to doubt they are there.
Practice makes it stick.
The Sweet Water
Problem 1 of 1
Sugar dissolves and the water goes clear. How do you know the sugar is still there?
1 of 4
What is all matter made of?
2 of 4
How many particles are in the jar after the sugar dissolves?
3 of 4
In which state are the particles spread through the whole space?
4 of 4
Does dissolving destroy matter?
Show what you know.
Question 1 of 1
Sugar dissolves and becomes invisible. What happened to it?
Claim, evidence, then reasoning.
The question
Your jar was sealed the whole time. Using the particle counts and the balance readings you saw, write an argument answering the question: where did the sugar go when it dissolved?
Evidence you can use
Fill in all three boxes. The reasoning box is the one that matters most.