Science Review

Science Review

Waste in Our World Review

Before the unit test, you should:

ü Be able to define the following words:

·        Biodegradable - able to break down in nature

·        Compost - organic matter that is broken down usually in an outdoor bin.  The resulting material is great fertilizer.  Worms can also be used in composting as their castings are very nutritious for plants.

·        Decomposer - organisms that break down the cells of dead plants and animals into simpler substances

·        Dump - where people dispose of garbage without sorting it

·        Fungi - a type of decomposer e.g. mushroom

·        Hazardous - dangerous or toxic

·        Litter - waste that is not place in the proper container and is left to lie around

·        Waste - materials that are no longer needed by people or animals

·        Landfill - a controlled area of land where waste is disposed of properly.  Waste is buried each day, and care is taken to prevent material from leaching into the soil and water table.  Eventually the land can be repurposed as a park or golf course.

ü Understand what items should be composted, recycled, reused or thrown away.  E.g. fruit/vegetable peelings, coffee grounds, newspaper, eggshells, etc.

 

ü Be able to give examples of different decomposers found in the soil.  E.g. centipedes, earthworms, fungi, lichen, etc. 

ü Know the difference between toxic and non-toxic and be able to give examples of each.  E.g. Toxic materials have the hazardous symbols on them and are harmful such as cleaners, paint, nail polish remover, battery acid, etc.  Non-toxic materials are safe and can be used by people in place of toxic cleaners such as vinegar, baking soda, lemon juice, etc. 

ü Be able to identify the hazardous waste symbols.  I.e. corrosive, explosive, poisonous, flammable 

ü Review the different types of packaging available when you buy something.  I.e. look for products with less packaging and/or packaging that is recyclable or reusable. 

ü Be able to identify the garbage R’s and examples of each.  Recover, resources, recycle, reuse, responsibility, regulations, reduce, rethink, repair

Lights and Shadow Study Guide

1. What is a source of light?  Something that can make its own light.
   Light bulb, sun, screen
2. What does the word luminescent mean?  It glows in the dark.
3. What are some examples of luminescent objects?  Glow stick, ceiling stars, glow in the dark tattoos
4. What is a reflector of light?  An object that light bounces off of, you can’t see it in the dark (lake, book, iron)
5. What makes a good reflector?  A smooth and shiny surface
6. What are some objects that would make good reflectors? Mirror, coins, spoon
7. Does a light beam directed at a mirror reflect off the mirror at a different angle?  No. Same angle.
8. What is the angle of incidence?  The angle that the light is reflected off a mirror. Angle of reflection = angle of light striking mirror
9. If you were to write a message on a piece of paper and hold it in front of a mirror. How would that message appear in the mirror and why does it appear this way?  Backwards.  Reflection.
10. How does light travel?  In a straight line.
11. What do the words transparent, translucent and opaque mean? Transparent: see through; translucent: can see through but not clearly; opaque: can’t see through it
12. What are some examples of transparent, translucent and opaque materials? Transparent: window; translucent: bubble wrap; opaque: book
13. Do all materials cast the same amount of shadows? No. Depends how much light goes through the object. 
14. Why do light rays bend as they enter water?  Water makes the light slow down.
15. What does the word refraction mean? Light bends
16. On a hot day, would you want to wear a dark or light shirt?  Justify your answer.  White will reflect the light off and the heat too!  Black absorbs the light and heat.
17. How does the size of a shadow change throughout the day – early morning to midday to late afternoon?  Shadow on opposite side; long in morning and afternoon; at midday it’s little and below you.
18. What happens to the size of a shadow as you move the light source away from the object?  It gets smaller
19. What is white light made up of?  All the colours of the rainbow.
20. What happens when light passes through a prism? It splits into 7 colours
21. What does ROY G BIV stand for? Red, orange, yellow, green, blue, indigo, violet.
22. What colours are produced when you combine the primary colours of light? They make white light
23. Why does a magnifying glass make objects appear larger?  It is curved outward.  It is a convex lens.
24. What is the focal point?  The point where the image comes into focus and flips.
25. What is a convex lens?  How does it work?  Curved outward. Makes things look bigger.  Bend rays of light to a common point.
26. What is a concave lens?  How does it work?  A lens that curves inward. Makes things look smaller.  Causes light to spread out.
27. Why do people wear glasses to read?  To correct their vision by moving the focal point.

SIMPLE MACHINES REVIEW

How can you give friction the slip?

1. Banana peels, snowboarding, ice
2. Soapy water, polishing
3. Smooth surfaces, skiing,

Do rollers make work easier?  Why?

Yes, because they roll and have less friction.

Name 4 ways we use “rollers” everyday.

1. To cook hotdogs
2. Steam rollers
3. Roller skates
4. Rolling pin
   
   

Will a load moved on rollers and a load moved on wheels be able to complete a slalom race in the same amount of time?  

No b/c rollers have to be replaced every couple. 

Wheels take the load with them!

Where will the largest movement in a wheel and axle occur – in the axle or in the wheel? WHY? Axle works harder but wheel moves a further distance

Will the placement of the axle in the wheels change the efficiency of the vehicle?

Yes, the axle s/b placed in the middle for a SMOOTH ride.

Do pulleys make raising an object easier? Yes, because I can then use my body weight to pull down. (Fixed pulley)

Will the use of a pulley reduce the amount of force required to lift a load?  A moveable pulley will reduce the effort (b/c there are two strings to support the load).

Will a moving pulley affect the effort required to lift a load?  (Single Movable Pulley experiment) YES!  MP cuts effort in half.

Does a fixed & movable pulley system affect the effort required to life a load? (Single Fixed & Single Movable Pulley experiment) HINT HINT HINT *** be able to draw a labeled picture of this pulley system** Yes, FP – force goes down; MP – cuts newtons (effort) in half

In a wheel to wheel drive system, will both wheels turn in the same direction?

No they go in opposite directions.

In a belt drive system, when do the wheels turn in the same direction?  When the belt goes around the wheels in one direction.

 In a belt drive system, when do the wheels turn in the opposite direction?  When the belt is twisted.

In a belt drive system does the size of the driver wheel affect the rate at which the driven wheel is turned?  (“Change the Driver” experiment).Yes, b/c when the

Big wheel is driver – small wheel faster

Small wheel driver – big wheel slower

How are dominoes like simple machines? They transfer energy to one another.

In a gear drive system, do gears of different sizes affect the speed of the driver gears (“Gear Together” experiment) Yes, small gears move faster compared to larger gears

Does changing the size and number of gears in a system affect the speed and direction of the gears? Changing the size of the gears affects speed and changing the number will affect direction.  Gears that touch go in opposite directions but when 2 gears have a gear between them they will go in the same direction.

Does changing the position of the fulcrum affect the force needed to carry a load?

Fulcrum closer to load – need LESS effort (b/c you have more LEVERAGE!)

Does changing the location of the effort on a third class lever affect its performance?

Yes, think of tweezers – best in the middle

In a 2^nd class lever, as the load moves closer to the fulcrum, is more or less effort required to lift the load? b/c you more LEVERAGE!

Machine: a device to make work EASIER

Force: push or a pull

Friction: slowing down of an object when they touch

There is _LESS_ friction between smooth surfaces than between rough surfaces.

Work: is the result of a force moving an object.

Fixed Pulley System: stays put, force goes DOWN

Load: “heavy” object that needs to be moved

Effort: the force that produces the action, “my hands”

Gears: a moving circle with teeth, transfer energy

Fulcrum: pivot point on a lever

Pivot: (think basketball), rotate on one foot, other foot stationary

A third class lever is a lever in which the EFFORT is in between the LOAD and the FULCRUM.

A first class lever is a lever in which the FULCRUM is in between the LOAD and the EFFORT.

A second class lever is a lever in which the LOAD is in between the EFFORT and the FULCRUM.

Two examples of a 1st class lever:. Teeter – totter; scissors

Two examples of a 2nd class lever:. Dolly, wheelbarrow

Two examples of a 3rd class lever:. Tweezers, bat, stapler