Repaso ciencias prueba global
Unit 7: Changes over time
-Growth and change:
People change constantly, from the day they are born until they die. The most visible changes are those that the body goes through.
-Fast and slow changes:
Besides physical changes, as children grow up, they go through personal changes. These changes are the result of personal life experiences. People learn from one another, from things that happen to them and from the environment.
Some changes are very slow, like learning to talk. Other changes are very fast, like learning to ride a bike.
-A timeline:
A person’s life story can be represented in a timeline. A timeline shows how time goes by and the changes that take place during that time.
A timeline is …ver más…

-Three states of water:
The changes of state that water can go through by heating or cooling it. Notice that changes of state are reversible.
When you heat water, it changes from liquid to gas. When this gas cools, it changes back to liquid. When water cools, it changes from liquid to solid; it becomes ice. If the ice warms up again, it changes from solid to liquid; it returns to its original liquid state.
All these changes of state occur as a result of adding or taking away heat. If you add heat, water changes from liquid to gas and from solid to liquid. When you take away heat, it changes from gas to liquid and from liquid to solid.
Water is the only substance that is found naturally in its three states: solid, liquid and gas.
*From solid to liquid = MELTING (FUSION) (+ HEAT)
*From liquid to gas = EVAPORATION (+ HEAT)
*From liquid to solid = SOLIDIFICATION (- HEAT)
*From gas to liquid = CONDENSATION (- HEAT)

Unit 10: Life cycles
-Descendants:
All living things are able to produce offspring or descendants. In order to have offspring, two living things must belong to the same species.
-Life cycles:
Animals, plants and human beings are born, grow and develop, reproduce and die. In other words, they have a life cycle.
A life cycle includes all the stages in the life of an organism, from birth to death. All living thing have a life cycle.
*Life cycle of butterfly:
Egg-larva-pupa-adult
*Life cycle of a