Grade 6 · Science · Earth
Follow the drop: where it goes and why it comes back
An interactive lesson on the water cycle, 11 questions
أ. نورة القحطاني
مدرسة ج
A student orders the stages before reading about them, then reads a thermometer and a measuring cylinder to work out how much evaporated and why.
This page is exactly what a teacher's published work will look like. Only the teacher is not real yet.
What the student does
- 1
Put the stages in order
Four cards: evaporation, condensation, precipitation, runoff. They order them before reading a single line of explanation.
- 2
Read the thermometer
A thermometer at 12 degrees, then at 45. They decide in which case the pond evaporates faster, and say why.
- 3
Measure what left
Two measuring cylinders: one before the dish went into the sun and one two hours later. They read both and work out the difference.
- 4
Answer the last question
If rain has been falling every winter for millions of years, why has the sea not overflowed and the land not dried out?
What's inside
- 4 cards to order the stages of the cycle
- A thermometer the student reads themselves
- Two measuring cylinders whose difference they work out
- 11 questions marked the moment they are answered
Outcomes
Orders the four stages of the water cycle and names each one.
Links a rising temperature to a faster rate of evaporation by reading a thermometer.
Works out how much water evaporated from two readings of a measuring cylinder.
Explains why the amount of water on Earth stays the same however long it keeps raining.
What the teacher focused on
They draw a circular arrow and think they have understood the cycle. I asked one of them where the water is right now, and they had no idea what to say.
Teaching strategies
- Ordering before naming
- Reading an instrument instead of memorising a number
- One question that returns at every stage
She has the student order four cards rather than watch the cycle animate. An animation is watched once and leaves no room to be wrong; ordering forces them to decide what follows what, and then shows them where they decided wrongly.
Questions from inside it
- 1Order these: precipitation, evaporation, condensation, runoff. Which comes first?
- 2The thermometer reads 45 degrees. What is happening to the pond water now?
- 3The cylinder held 250 millilitres. After two hours in the sun it holds 190. How much evaporated?
Curriculum
- Grade
- Grade 6
- Subject
- Science
- Unit
- Earth
- Taught in
- Saudi Arabia
Where this lesson sits in the curriculum
The same lesson appears in these countries' curricula. One page, five paths to it.
When to use it
The explanation
The sun warms the sea, the lakes and the soil, and molecules break away from the surface and rise as vapour. That is evaporation, and the warmer it gets the more of them break away. The vapour cools as it climbs, condenses onto specks of dust and becomes the tiny droplets a cloud is made of. When the droplets grow too heavy for the air to hold, they fall as rain or snow. What falls either runs along the surface to the rivers and the sea, or soaks into the ground. Through all of it the water neither increases nor decreases — it changes place and state, and comes back to where it began.
Common mistakes it catches
What you can see is water that has already condensed back into droplets. Water vapour itself is invisible. Look at the gap between the spout and the first white wisp — that gap is the vapour.
Washing dries on the line at 25 degrees. Evaporation happens at the surface at any temperature; boiling happens throughout the liquid at one particular temperature.
The amount on Earth has been about the same for millions of years. Ask: where did the rain come from in the first place? From the sea that evaporated a few days ago.