Reversible/Irreversible
Irreversible change
How many states of matter are there?
What are they?
Three states
Solid, liquid, gas
What is weathering?
When rocks break into smaller pieces
What is erosion?
When rocks, soil, dust and sand are moved to new places.
Which change can actually be good? Weathering or erosion? Why?
Weathering - can create soil
When something changes but can be undone or return back to normal, it's called ....... .
Reversible change
If you put ice in the sun, the ice ...... .
If you put a lemonade juice in the freezer, the juice ...... .
Melts
Freezes
Weathering can take (two days / thousands of years) to happen
Thousands of years.
Dust, sand, rocks and soil
A huge row of trees used to stop wind from blowing away farmlands is called...... .
Windbreak
Is this reversibke or irreversible?
-melting a chocolate bar
-cooking rice
-burning wood
Reversible
Irreversible
Irreversible
For melting to happen, you have to add ....... .
heat
When wind carrying sand pieces keeps hitting rocks and the rocks break into smaller pieces, this is known as weathering by........ .
Wind
When rivers carve out land and get deeper and wider, creating canyons, this is known as erosion by....... .
Water
A new technology that looks like a "net" used to stop landslides from starting is called .....
Wires and brackets
Melting and freezing are........ changes.
Cooking and burning are .......... changes.
Reversible
Irreversible
To cook food you have to add (too much heat/the right amount of heat)
To burn food you have to add (too much heat / the right amount of heat)
The right amount of heat
Too much heat
When it rains into the cracks of rocks and then winter comes and the water turns into ice, expanding the cracks and breaking the rocks apart, this is known as weathering by ....... .
Water and ice
When glaciers move rocks to a new place, this is known as erosion by ....... .
Ice
A quick fix to a erosion by flooding is putting..... .
But a permanent and strong fix is ...... .
Sandbags
Dikes
True or false: If a food is rotten or gets spoiled, it's an irreversible change because it changed forever.
True
Give an example of a food you can cook at home and tell us which property can change in that food.
accept reasonable answers
A scientist discovered that a rock broke into smaller pieces after 200 years. What could have happened to the rock? (Give details)
Accept reasonable answers.
Soil can be blown away from farmlands by wind. This is known as erosion by ...... .
Wind
Imagine you live in a country that gets flooded a lot!
Would you rather use sandbags to protect your country from erosion by flooding or dikes? Why?
Accept reasonable answers