7k forces
DESCRIPTION
7K FORCES. Forces. What is a force ? What unit is force measured in? What do we use to measure forces ?. FORCE STATIONS. Go round the stations . Write at least two sentences for each station. Weight and mass. What is the unit of weight ? How can you measure weight ? - PowerPoint PPT PresentationTRANSCRIPT
7K FORCES
What is a force?
What unit is force measured in?
What do we use to measure forces?
Forces
Go round the stations.
Write at least two sentences for each station.
FORCE STATIONS
What is the unit of weight?
How can you measure weight?
What is the unit of mass?
How can you measure mass?
How do I change weight to mass on earth?
Weight and mass
Aim: To investigate the relationship between weight and mass.
Object Mass (g) Weight (N)
Number of pieces
Mass (g) Weight (N)
Now, change mass to kgObject Mass (g) Weight (N) Mass (kg)
Graph
Level 3 When the mass is bigger the weight…Level 4 Number examples
e.g. when the mass is 10g the weight is 0.1NLevel 5 Why does this happen? Can you describe the pattern using a formula?
Weight = …. Are there any results that do not fit the pattern?
Conclusion
Running on the moonhttp://youtu.be/CyOt6RUs9mE
Jumping on the moonhttp://youtu.be/HKdwcLytloU
What force always acts downward on an object (on earth)?
What force pushes up on an object in water?
Floating or sinking
Aim: To investigate which is the best material to make a float?
How do you calculate density?
What is the unit of density?
What is density?
Density
Aim: To investigate which is the best material to make a float.
Why?
What is the same and different about the cubes?1. Brass
2. Copper3. Aluminium4. Iron5. Zinc6. Tin7. Lead8. Polythene9. Hard wood10. Soft wood11. Cork12. Acrylic
Remember cm3 is the same as mlL
H
D
VOLUME = L X H X D
FINISH YOUR RESULTS TABLE
DENSITY = MASS(G) / VOLUME (CM3)(/CM3)
Use these key words to explain what you have found out about floating and sinking.
upthrust weight force
float sink buoyancy density
Less dense denser
Which material would you use to make a float?Give 3 reasons why.
Conclusion
Does density change if there is a bigger or smaller piece of the material?
How does salininty of water affect whether an object floats or sinks?
Density 2
7 layer density column demo
Aim: To find out how the number of weights a scuba diver needs changes with where they swim.
The water will represent: The Mediterranean, The Baltic sea, The Dead Sea, The Black Sea and a Lake
Write a prediction with the word BECAUSE Write down the independent, dependent
and control variables
You put weights in water with different salinity and measure the weight.
What are the two types of force?
Name some forces.
Types of force
Separate the cards into two groups
FrictionAir resistanceWater resistance
MagnetismStatic electricityGravity
What happens if forces are balanced?
What happens if forces are unbalanced?
Balanced and unbalanced forces
One where the forces acting are the SAME (balanced)
One where the forces are DIFFERENT sizes (unbalanced)
Separate the cards into two groups
Balanced Unbalanced
Change shape
Go faster (accelerate)
RWC 2011 highlights http://youtu.be/Cq6lcH7NKAw
Tackles http://youtu.be/aD_1sone-Mk
Line outs http://youtu.be/OCQfggoUSNU
VIDEOS
What is friction?
What is friction in air called?
What is friction in water called?
Friction
Can you feel the friction?
Rub your hands together
Friction and energy
When friction occurs heat energy is produced
Kinetic energy Heat energy
Friction Friction is a force which opposes the motion
of 2 objects It makes it harder for things to slide Friction can occur between solids, and for
anything moving through a liquid or gas
What examples of friction can you think of?
FRICTION STATIONS
http://youtu.be/jSu0Tvlm6LY http://youtu.be/QMW_uYWwHWQ?t=2m17s
Mythbusters phone books
This hotel is built on sand
Friction 2 When is friction useful?
When is friction not useful?
How can friction be reduced?
Put the cards in order from most to least friction
When do we want to reduce friction?
E.g. A bicycleFill in this table naming the parts of a bike where friction is wanted or not wanted.
Friction is wanted
Friction is not wanted
- Gripping onto handlebars
- In the axle where the wheel turns round
Tyre
Handlebar
Seat
Axle
PedalChain
Gears
Wheel
Brakes
How can friction be reduced?
Slick sliding soap practical
You will be sliding soap down a slope, you will investigate how to make it slide further.
Aim: Prediction: Variables: Independent, dependent, control
Results- Homework Plot a bar chart
Conclusion◦ Describe the results:
With nothing the soap went ____cmWith oil the soap went ____cm.With water the soap went ____cm.
◦ Which had most friction?
◦ Which had least friction?
Results- Homework Plot a bar chart
Conclusion◦ Describe the results:
With nothing the soap went ____cmWith oil the soap went ____cm.With water the soap went ____cm.
◦ Which had most friction?
◦ Which had least friction?
◦ Why?
◦ How does this relate to real situations
What happens to a spring when you add masses to it?
When is this useful for us?
Springs
Aim: To investigate why elastic is used in bungee cords.
Success criteria:
Draw a scientific diagram of the experiment
Design a results table
Results
Graph
What are the units for speed?
How do you calculate speed?
Speed
You will be investigating how one factor affects friction (not liquids)
This practical will be assessed for AF3, AF4 and AF5
Assessed practical