Forces can be pushes or pulls that act on objects. A force can slow down, speed up, change direction of, or cause motion in a stationary object. Friction opposes motion between surfaces in contact and different surfaces have different amounts of friction. Forces can be useful to prevent slipping or allow farther travel, but can also cause wear, heat, and tear as nuisances.

1. Science Year Six
Revision

2. Force
A ____ is an action of moving an
object away, a ____ is an action
of bringing an object towards us.
push, pull
True or false~
Forces cannot be seen. ( )
We can feel the effects of force. (
)
A force is a pull or a push. ( )
True x 3

3. Force
What can a force do?
Slow down a moving object. ( )
Change the shape of objects. ( )
Cause a stationary object to move.
( )
Speed up a moving object. ( )
Stop a moving object. ( )
Change the direction of a moving
object. ( )
Change the size of objects. ( )

4. Force
____ is a force that opposes motion.
Friction
Different types of ____ in contact
have different ____ of friction.
surface, amount
A ____ ____ has less friction while a
____ ____ has more friction.
smooth surface, rough surface

5. Force
We can reduce friction by using~
ball bearings
talcum powder
rough surface
lubricants
dry surfaces
rollers
air cushion

6. Force
Force can be a nuisance. It
produce ____ and causes ____
and ____.
heat, wear, tear
Force can be useful. It prevents
things from ____.
slipping
A smooth surface enables a
moving object to travel ____.
farther

7. Movement
A fast moving object takes a ____
____ to reach its destination.
shorter time
A fast moving objects travel a
____ ____ in a given time.
longer distance
We can measure how fast or slow
an object moves by using ____.
speed

8. Movement
Speed involves ____ and ____.
distance, time
The unit for speed are ____,
____ or ____.
kilometre per hour, metre per
second, centimetre per second
Speed can be calculated by using
the formula ____.
Speed = distance / time

9. Food Preservation
Spoilt food can be detected by their ____,
____, ____ or ____.
taste, touch, smell, sight
____ can cause food to spoil.
Microorganisms
Microorganisms need ____, ____, ____,
____ and ____ to grow.
air, water, nutrient, suitable temperature,
suitable acidity

10. Food Preservation
Microorganisms will grow within a range of
____ and ____ degree celcius.
5, 65
____ and ____ are processes of preserving
food by heating and then sealing it in an
airtight container.
Bottling, canning
____ removes most water from food.
drying

11. Food Preservation
____ and ____ slow down the action of
microorganisms.
Cooling, freezing
____ keeps food by sucking air out from its
packaging.
Vacuum packing
____ is the process of drying food with
smoke for a long period of time.
Smoking

12. Food Preservation
____ dips food into liquid wax to prevent
growth of fungi and loss of moisture.
Waxing
____ means heating food to a certain
temperature for some time followed by
rapid cooling.
Pasteurization
____ kills most bacteria.
Boiling

13. Food Preservation
Sugar, vinegar or other acids are used in
____ food.
pickling
____ is an age-old way of preserving food.
Salting
We need to preserve food so that they will
____ ____, easy to transported and ____, as
well as to reduce ____ ____.
last longer, store, food wastage

14. Waste Management
____ are things that we no longer use and
would throw away.
Waste
Food and plants that are thrown away are
known as ____ ____.
organic waste
Waste that come from our home, factories
and agriculture are called ____ ____.
chemical waste

15. Waste Management
Improper disposal of waste may cause
____, ____, ____, ____ or ____.
air pollution, water pollution, acid rain,
sickness/diseases, flash floods
The local authorities provide garbage
trucks to collect waste and sent to
____.
landfills
We can burn the waste in an ____.

16. Waste Management
Some waste ____ while some do not ____.
decay
____ help the waste to decay, we call this
process ____.
Bacteria, decomposition
Waste that decay add ____ to the soil.
nutrient
Decaying waste lower the ____ content in
water.
oxygen

17. Waste Management
True or false~
Biodegradable plastic can decay.
Domestic wastes is waste that is
processed from the factory.
Decaying waste produce bad smells
and toxic chemicals.
Compost is toxic to plants.
Washing with polluted water may cause
irritation of the skin.