Teaching materials · Grade 7
The Lesson Book
Classroom materials by Elena Márquez, with notes on when to use them and what to listen for.
Grade 7 · Matter and energy
Where did the water go?
One familiar observation becomes a practice in asking better questions. These materials use constructed observations for the demonstration.
Plan the comparisonLesson plan · 45 minutes
Two puddles start out the same size. At lunch, one is gone. What could explain the difference?
- Draw an initial model before introducing the word evaporation.
- Use identical dishes and equal starting volumes. Record the placement and time.
- Compare measurements, then name what the setup cannot isolate.
Read a measurement tableStudent handout · Sample data
Describe one change the measurements support. Write one question the measurements leave open.
- Mark the units and the starting amount.
- Subtract the last reading from the first for each dish.
- Circle one condition you would control more closely in a second trial.
Revise the explanationExit ticket · 5 minutes
Use one number from the table to explain what changed. What would help you say why?
- Make a claim about what happened in these dishes.
- Point to the comparison that supports it.
- Distinguish a possible explanation from a tested explanation.
From the teacher’s desk
The word can wait.
I ask students to draw what they think happened to the puddle before naming evaporation. It gives me something to teach from. A drawing where the water sinks into concrete calls for a different follow-up from one where the water rises.
On the second pass, students can use sketches, spoken explanations, or short written notes. Everyone returns to the same question. What does our evidence support?
Classroom sample / water remaining
Check the dishes.
- Window
- 8 mL
- Shaded shelf
- 9 mL
The dishes have lost different amounts. Which conditions should we record?
Tacoma, Washington
I’m Elena Márquez.
I teach middle-school science. I build lessons around observations students can make, argue about, and measure again. My favorite classroom sound is someone asking their table to wait while they check a number.