Mixing Materials: What Dissolves in Water?
Observe, predict, and explain how materials mix with water
Mixing Materials: What Dissolves in Water?
Observe, predict, and explain how materials mix with water
Science - Grade 2-3
- 1
Mia stirs a spoonful of sugar into a cup of water. After a little while, she cannot see the sugar anymore. Did the sugar dissolve? Explain your answer.
A material dissolves when it seems to disappear into the liquid but is still there.
Yes, the sugar dissolved because it mixed evenly into the water and could no longer be seen as separate grains. - 2
Liam adds sand to a cup of water and stirs. The sand sinks to the bottom. Did the sand dissolve? Explain your answer.
No, the sand did not dissolve because it stayed as small grains and settled at the bottom of the cup. - 3
Circle the materials that usually dissolve in water: salt, pepper, sugar, small rocks.
Think about materials that seem to disappear when stirred into water.
Salt and sugar usually dissolve in water. Pepper and small rocks usually do not dissolve. - 4
A student mixes salt into water and tastes one tiny drop with permission from the teacher. The water tastes salty. What does this show about the salt?
This shows that the salt dissolved in the water, even though the student could not see the salt grains anymore. - 5
Look at this observation: Cocoa powder made the water brown, but some powder floated on top and some sank. Did all of the cocoa powder dissolve? Explain.
If pieces are still visible, they have not completely dissolved.
No, all of the cocoa powder did not dissolve because some of it was still visible floating or sinking in the water. - 6
Nora wants to test whether baking soda dissolves in water. What should she do after adding baking soda to the cup?
She should stir the mixture and observe whether the baking soda disappears into the water or remains as visible powder. - 7
Two cups have the same amount of water. Cup A has warm water, and Cup B has cold water. Sugar is added to both cups. In which cup might the sugar dissolve faster?
Warm water can make mixing happen faster for some materials.
The sugar might dissolve faster in Cup A with warm water because warm water often helps some solids dissolve more quickly. - 8
A student says, "The salt disappeared, so it is gone forever." Is the student correct? Explain.
Dissolved does not mean gone.
No, the student is not correct. The salt dissolved into the water, so it is still in the water even though it cannot be seen. - 9
Which observation is stronger evidence that a material dissolved: it changed the water color evenly, or it stayed in clumps at the bottom? Explain.
Changing the water color evenly is stronger evidence that a material dissolved or mixed evenly. Clumps at the bottom show that some material did not dissolve. - 10
Jada tests three materials in water. Salt disappears, rice sinks, and sugar disappears. Which materials dissolved?
Use the observations to decide which materials mixed evenly with the water.
The salt and sugar dissolved because they disappeared into the water. The rice did not dissolve because it sank and stayed visible. - 11
Draw or describe what you might see after stirring gravel in water. Would the gravel dissolve?
The gravel would still be visible in the water and might settle at the bottom. The gravel would not dissolve. - 12
Why is it important to use the same amount of water when comparing how different materials dissolve?
A fair test changes one thing at a time.
Using the same amount of water makes the test fair because only the material being tested changes. - 13
A student mixes blue drink powder into water. After stirring, the whole cup of water is blue with no powder at the bottom. What can the student conclude?
The student can conclude that the blue drink powder dissolved in the water because it mixed evenly and left no visible powder. - 14
Choose the best science word to complete the sentence: When a solid mixes evenly into water and seems to disappear, it ____. Word choices: freezes, dissolves, floats.
The word describes what sugar does in water.
The correct word is dissolves. When a solid mixes evenly into water and seems to disappear, it dissolves. - 15
Plan a simple test to find out whether flour dissolves in water. Name one thing you would do and one thing you would observe.
Scientists use actions and observations to learn what happens.
I would add a small spoonful of flour to water and stir it. I would observe whether the flour disappears into the water or stays visible as cloudy clumps or powder.