Grade 9 Science: SNC1D

Downloadable link to Ontario Curriculum for Grade 9 Academic Science

Basic Intro video

When you think of experiment, you might think randomly mixing chemicals together, but its not really an experiment. An actual scientific experiment, which is a series of steps performed to find out an answer to a scientific question, has certain criteria to follow.

• It has a clear, well defined question formatted, with key question works like : (Does, How, Why, When, etc).

For example: Does water temperature affect plant growth in cm?

See how a variable is defined

• It tests only one variable at a time (usually). For the reasons we mentioned when we talked about variables

• It has repeated trials, or replications. This reduces the likelihood of outliers such as random chance factors, experimental errors, etc, and from the average of the replications you can draw a more accurate conclusion. Remember, just because a result occurs once doesn't mean it is the correct result, it could very well be an outlier.

For example, if you test how plants grow in plain water vs salt water, and you see how a plant grew 10cm in salt water and only 2cm in plain water, that isn't necessarily correct. For all you know you could have a data set like this:

Plant Growth in Water Types

Test Number Plain Water Salt Water

1 2cm 10cm

2 10cm 5cm

3 12cm 3cm

4 5cm 1cm

5 15cm 0cm

6 8cm 2cm

See how the data set you got compares to the first test, which is definitely an outlier?

Example Experiment:

Question: Does the type of shoe you wear affect jump height in cm?

Independent variable: Type of shoe worn

Dependent variable: Jump height in cm

Control variables: Surface of jump, Person jumping, Tiredness/energy levels of person jumping, Quality/age/wear of shoes, etc.

So in order to account for as many control variables as we can, we must have the same person jumping, on the same surface, with new quality shoes for each brand.

Remembering the principle of reiteration/repetition.

Test Results (random results)

Test Number Reebok Adidas Nike Saucony

1 45cm 55cm 39cm * 51cm

2 40cm 52cm 40cm 43cm

3 32cm 53cm 37cm 42cm

3 35cm 48cm 35cm 38cm

4 31cm 45cm 30cm 39cm

6 28cm 42cm 29cm 36cm

Notice how the jump height generally decreases as more tests are done? This means the person is getting tired, and the earlier tests are more valid than the later ones.

*Also notice that Saucony has an outlier of 51cm in the first test when all the rest average in the late 30s and early 40s

Making a proper lab report is a key skill for the world of science. No matter it be biology, chemistry, or physics, it's an essential skill. And there is a set of criteria you must follow

This is a very standard method of answering a question, and many teachers look for all the steps when you answer a question. So be sure to follow GRASS/GRASP and don't miss any steps. Some teachers deduct points for missing steps even if the answer is accurate. You need a system like this, because if a question is very hard, and has multiple values you need to solve for, or a complex equation, you need to keep track of your work so that you don't make errors.

Here are the five steps you must follow below:

Given: What values do you have.

Required: What values do you need

Analyze: Steps you take to reach the solution

Solution: What is our solution

Statement/Paraphrase: A sentence to describe the solution and paraphrase the question, insert the solution.

Example Problem:

For the purposes of demonstration we will use an equation (that we will get to later) called Ohm's Law, which is V = I x R (or Voltage = Current x Resistance).

The problem is. For a device which has a potential difference of 240V, and has a current of 40A, what is the resistance?

So we will use the GRASS method.

First, what values are we provided? (Given)

We are given the potential difference, which is the V value, and the current, which is the I value.

So we know that V = 240 V and I = 40A

Secondly, what values do we need? (Required)

We need the R value of the equation, which is the resistance in Ohms (Ω).

Thirdly, we need to use this information to find the answer (Analyze)

So we have the equation: V = I x R. So we need to use algebraic inversion to find the R value. R = V / I

V = I x R

240V = 40A x R

R = 240V / 40A

Solution: R = 6 Ω

Statement: The device has a resistance of 6 Ω

And that's how to use GRASS

Summary of Unit:

Summary of Chapter

In nature there are many diverse relationships between organisms, and there are a great many organisms in nature. This diversity allows nature to be resilient, however, human activity can threaten that delicate balance which depends on many factors.

Population: The number of organisms of a specific species/type. For example the total number of grey squirrels living in Rouge Park

Community: All living things in a particular area. For example, the flora(plant) and fauna(animals) of Vancouver

Ecosystem: All the interactions between organisms as well as to the abiotic factors: the living and non living parts of the environment.

Biome: Groups of similar ecosystems grouped together, the extent of each group of ecosystems across the world (biome map below)

Biosphere: Every part of the Earth where living things reside. This is one of the -spheres of the Earth, the others being the lithosphere: the entire surface of the Earth's crust, the hydrosphere, the entirety of the Earth's water surface, all the water bodies on the Earth, and the atmosphere, the layer of gases around and above the Earth's crust.

Order of smallest and more localized to larger and more broad

:Population -> Community -> Ecosystem -> Biome -> Biosphere

Biotic: Living factors. Fauna and flora. Any living part of the natural environment, any living creature, really.

Any living thing which either falls into Prokaryotes: (Monera: Bacteria and blue-green algae(cyanobacteria) which are single celled organisms with no membranes for their organelles and no distinct nucleus (instead possessing nucleic material), the name being Pro (pre) karyote (nucleus), or Eukaryotes: (Animalia, Plantae, Fungi, Protista), which are either multicellular or unicellular organisms which have a distinct nucleus and organelle membranes, the name being Eu (true) karyote (nucleus)

Abiotic: Any non-living aspect of the natural environment. For example, water, oxygen, sunlight, energy, the physical landforms and features, etc.

Habitat: The immediate living space of an organism. For example the tadpole's habitats are: ponds, wetlands, or a similar water body. A grasshopper's habitat could be a log, a mole's habitat is an underground burrow, and so on.

Air/water pollution: Air and water pollution is a problem for many organisms but due to the sensitivity of frogs' skin, frogs are particularly affected by it: they breathe through their skin when in water, so every exposed part of their body in polluted water will not only develop the skin problems which result from exposure to pollution, but also the frogs will be breathing in the pollution through their skin, and circulate it throughout their body, which may make them sick, or even die. The pollution may also hinder their ability to breathe through their skin. That means that even relatively "low" concentrations of pollution can seriously harm frogs.

Habitat Loss: Frogs have a very specific need for habitats, needing both a water body like a pond, a stream, or wetland to lay their eggs, and allow the tadpoles to grow, and a land area like a forest or a grassy field so they can catch insects, a place with decent cover so they can be shielded from predators like snakes and birds. They also need a safe way to get back and forth between the two environments. As you can see, a very specific set of conditions is needed. Alter even one thing, like draining the wetland, or clear cutting the forest, and the frog population will seriously be harmed, whether it be difficulty to lay eggs safetly, increased susceptibility to predators, or more difficulty to hunt insects.

Excess UV Radiation: Frogs have very sensitive skin, which can be easily burned, and excess UV radiation can seriously harm frogs' skin, drying it (which can harm frogs' ability to breathe through their skin) and if that ability is blocked, it will be deadly for them in water, as well as UV radiation causing sunburns and even skin cancer. This is reflective of the fact that all over the world, UV related skin cancer is rising all over the world, for humanity. Some frogs living at high altitudes (prone to a higher UV concentration) have adopted a semi-resistance to the UV concentrations by having adaptations such as darker skin (more pigment), and darker colored eggs. But even those adapted frog species cant adapt fast enough to keep up with the adverse human impact. Anyways, why even is there such a high amount of UV radiation that is steadily rising? That's the next reason

Anthropogenic Climate Change: The sheer amount of environmental changes that are happening with the climate, temperature, sea-levels, the physical landforms, etc are happening either because of climate change, or contribute to climate change. Naturally, these changes are very harmful to the health of the frog species. Higher temperatures will burn/harm the frogs' skin, rising sea levels and changed landscapes will alter their lifestyle and hunting patterns. These and the many other adverse changes will seriously harm the frogs.

Deforestation: Deforestation, the systematic harvesting of forests for lumber, or clearing land for agricultural use (farming), or for other uses such as building infrastructure, harms the natural ecosystem in many ways. Since in deforestation the trees are not replanted, this could have disastrous effects. Deforestation will result in habitat loss for many species, it will reduce tree cover for prey (to avoid predators) and predators(to avoid being seen by prey), and it will collapse the local ecosystem's food web by removing the main producers, and eliminate a source of food for many primary consumers. Deforestation will also result in an imbalance in the carbon cycle: trees convert carbon dioxide to oxygen via photosynthesis, and deforestation, combined with increased carbon emissions, will increase the carbon dioxide concentration in the air and reduce the oxygen concentration. This contributes to the greenhouse effect, see Anthropogenic Climate Change

Creation of Roads, Buildings, and Other Infrastructure: The creation of roads, buildings and other infrastructure will cause serious harm to the environment: Firstly the creation of these will result in habitat loss, and most likely needs deforestation to clear the land necessary for them. Secondly, roads being paved will harm the surface soil, and kill organisms living in it, as well as cause natural drainage problems and flooding: as water cant infiltrate (see Water Cycle) into the soil thats blocked by roads (and other infrastructure), and also this will disrupt the water table. in addition, the intensive mining and refining process for the resources needed to construct roads, buildings, and other infrastructure will not only deplete the resources necessary to construct them, but will also change the landscape, disturbing and harming many organisms, release pollution into the air and water, and release carbon emissions. The buildings and infrastructure will release pollution: air, water and light pollution too, (which harms animals which use the natural light to navigate and for other important purposes) and the buildings and infrastructure will also release much carbon emissions.

Manufacturing, Transportation, and Consumption of Goods: These three processes are very intensive and harmful to the environment: First of all, manufacturing the gods is a very resource intensive process, which requires much mining (adverse effects described in Construction of Roads, Buildings and Other Infrastructure). Manufacturing, transportation, and disposal (of all kinds, including recycling), is very energy intensive, and in many cases releases much pollution and carbon emissions. the harvesting of resources causes deforestation and habitat loss in many cases. Note: transportation of goods is a particularly carbon intensive/emitting process, which is often not acknowledged. In addition, due to marketing and business concepts such as planned obsolescence (objects being made to fail at some point) and perceived obsolescence (making customers have an obsessive need to buy the newest products, increased demand for the latest trendy goods which are often not much better than their predecessors), manufacturing (and by extension transportation and consumption) are "needed" to be increased to unsustainable levels, and also when the usable lifespan of goods is reduced, the number of goods disposed of is increased. This is an unsustainable practice.

Further Information:

Story of Stuff

Story of Electronics

Overexploitation: The unsustainable and often unethical use of a natural resource (biotic or abiotic) to the point where it becomes completely depleted. This can apply to our unsustainable use of fossil fuels (which contribute to the greenhouse effect), certain minerals, or the rapidly accelerating unsustainable use of resources that the vast majority of other organisms also need, such as land, water, and trees (lumber). It can also apply to our use of animals for food, and our use of animal parts for food/goods. For example overfishing using methods such as trolling, or the unethical (and now mostly illegal) use of animal parts for food ( shark fin soup), goods (ivory), and some traditional Eastern medicines (tiger paw). There are now much more ethical and often artificial counterparts to these items, and they are being used more.

Alien/Invasive Species: The accidental or deliberate introduction of a non-native species to a new environment.

Sometimes species are deliberately introduced to a new region to control a pest population, this is called a biological control. An example would be the parasitoid fly brought over to control the European Gypsy moth (also an invasive species).

Other times, new species are accidentally and unknowingly introduced to new areas, often as stowaways on transportation vehicles (the international transportation network that humanity has built enables global reach. This is a bad thing for the environment because invasive species can land anywhere). An example would be the brown tree snake stowing away on warplanes and cargo planes during WWII, and landing in Guam.

Regardless of how the species is introduced, it can cause devastating damage to the environment. Invasive species are often far more efficient than their native counterparts, allowing the invasive species to easily outcompete native species occupying that niche, and in many cases the native species run out of resources (as the invasive species takes most of them), and are driven to endangerment, or even extirpation/extinction. For example, the purple loosestrife is an invasive weed introduced to North America, which successfully outcompetes many of its native counterparts and drastically reduces plant biodiversity.

Invasive species can also, with a high degree of efficiency, prey on native species (some of which have no natural predators), which have no natural adaptations to resist/avoid predation from the invasive species, and in many cases the prey species are driven to endangerment/extirpation. For example, the brown tree snake, when accidentally brought to Guam, it preyed on the local bird populations (including the Guam Rail), which had no natural predators, and thus no adaptations to resist predation: many of the birds didn't even recognize nearby snakes as threats. Many bird species were thus driven to extinction or extirpation.

Invasive species introduced for pest control also have mixed results. Sometimes they do not succeed in eliminating the pest, and in many cases, they also prey on non-threatening species as well. In general, invasive species are a serious threat to biodiversity.

Further Activity:

Documentary about Invasive Species (Note: Click Episode 4: Alien Invasion)

Producer/Autotroph: An organism which makes its own food and synthesizes its own energy by one of two processes (listed below). Producers are preyed on by primary consumers. (Auto meaning self, and troph meaning energy/nourishment)

Photoautotroph: Producers which perform the chemical reaction of photosynthesis (converting the sun's energy and carbon dioxide into breathable oxygen, water and glucose (which it uses for food/energy). Plants and blue-green algae (cyanobacteria) are photoautotrophs.

Chemoautotroph: Producers which convert inorganic chemical compounds into organic ones, getting energy from chemical reactions and gain organic compounds from carbon dioxide. Certain bacteria species are chemoautotrophs. They often live in extremely hostile places such as deep sea vents.

https://en.wikipedia.org/wiki/Chemotroph#Chemoautotroph

Consumer/Heterotroph: Organisms which can't create their own energy, and thus must eat either producers, other consumers, or both. Are classified as herbivores, omnivores, and carnivores.

Primary Consumer: An organism which doesn't eat other consumers, and only eats producers. Is preyed upon by secondary consumers, which are in turn preyed upon by tertiary consumers, which are preyed on by quaternary consumers.

Note: in a food web, an organism which is one level of consumer, can simultaneously be another level of consumer as well.

For example.

One path could be: Grass -> Mouse -> Snake -> Hawk (Mouse is primary consumer)

and another path could be: Grass -> Grasshopper -> Mouse -> Snake -> Hawk (Mouse is secondary consumer which bumps up snake and hawk to the levels above)

Carnivore: A species which mainly or fully eats other consumers. Not to be confused with omnivores which eat both other consumers, and producers as well.

Hypocarnivore: 50% or less of their diet consists of meat. Sometimes grouped into the omnivore category. Examples include: the grizzly bear, the brown bear, and the kinkajou.

Mesocarnivore: 50 - 70% of their diet consists of meat. The rest consists of non-vertebrate animals including insects, as well as plant matter or fungi. Examples include: The red fox, the raccoon, and the mongoose

Hypercarnivore: More than 70% of their diet consists of meat. The rest consists of plant matter or fungi. Examples include: the lion, the polar bear, and the tiger.

Decomposer: Organisms which break down detritus for their own nourishment, thus allowing the nutrients locked in the detritus to be accessed by producers, thus re-starting the nutrient cycle. Examples of decomposers include many bacteria and fungi species, as well as some animals such as earthworms.

1. Energy (and matter) cannot be created or destroyed, only cycled between forms). Because in nature things always cycle.

Summary of Unit:

Insulators:

Insulator are materials which do not easily allow electrons to flow through them, and thus, are very likely to accumulate static charges.

Good insulators include: plastic, wood, rubber, and clay (ceramics). Many nonmetals are usually good insulators

Conductors:

Conductors are materials which easily allow electrons to flow through them, and thus, are unlikely to accumulate static charges. This property makes conductors very useful in electronics, good conductors of current electricity, they can be used as wires in circuits. (See Current Electricity)

Metals are usually good conductors, due to their electron properties. Examples of good conductors include: copper, gold, platinum.

There are three main ways objects can charge, accumulate static charges.

Charging by Friction:

Charging by friction involves rubbing two objects together

- In charging by friction, two neutral objects are rubbed together and one gets the electrons and the other loses electrons.

- in order to determine which object will get and which will lose electrons we use the electrostatic series

two factors affect the amount of static charge produced :

material (where they are found relative to each other on electrostatic series)

duration/strength of friction

any charge that is transferred onto an insulator will stay where it is transferred

- eg. wherever the electrons were rubbed is where they will stay

two factors that affect the amount of static charge produced are type of material for both objects and duration of friction.

Both items neutral

Items being rubbed onto each other

Affected by triboelectric series

Charging by Contact:

brief touch

one charged, one neutral or opposite charge

not affected by triboelectric series, rather by which object is

Rules of Charging by Contact:

Charging by contact is NOT affected by the triboelectric series, rather by which object is more positive

Object which is more negative gives electrons to object which is less negative

By end of charging by contact, both objects have the same charge.

More info

Charging by Induction:

A way of charging an object without touching it with any charged object.

What's required: A charged object, a neutral object, and a ground.

Steps:

1. Bring the charged object close to but NOT touching the neutral object. This will result in induced charge separation. (The part of the neutral object close to the charged object will have the opposite charge of the charged object, and the part of the neutral object facing away from the charged object, will have the same charge as the charged object.)

2. Connect a ground to the side of the neutral object facing away from the charged object. Now electrons will flow into (or out of) the object until that side is neutral. Then remove the ground

3. DO NOT connect the charged object to the neutral one at any point of this process. After you remove the ground, the charged side of the object would spread out to fill the object. Remember, the charged side of the neutral object has a charge opposite to the charged object, so that charge spreads out.

4. The objects end up with overall opposite charges relative to each other.

Example with a negatively charged object:

Negatively charged balloon, and neutrally charged box. Negatively charged balloon repels the electrons in the box, has positive charge on side facing balloon. Discharge the negatively charged side of the box

Example with a positively charged object:

Positively charged balloon, and neutrally charged box.

More info

Induced Charge Separation:

no permanent change. Because unlike (above), there is no ground to make object "neutral".

Needs a charged object and a neutral object. This is step 1 of Charging By Induction

Check out this link if you want some additional info on the three types of charging: Three Types of Charging

Lighting is a very powerful source of electricity, far hotter than the sun, an impressive force of nature. But did you expect that the same principles behind you getting a static shock of you rub your feet on a rug, and then touch a metal doorknob, also allow for lightning to happen? Lets see how lightning works below:

Steps of lightning below:

1. Water droplets evaporate and go up. the water droplets start off neutral because they were on the ground, which is neutral (as we know from Discharging Charged Objects)

2. The water droplets which enter the clouds from below collide with ice and water droplets (and other precipitation from the clouds) which are heading downwards to exit the clouds, and electrons are knocked off of the water droplets which entered the cloud

3. The electrons accumulate on the bottom of the cloud, and the positive charge is on the top of the cloud. The electrons can't go to the positive charge at the top of the cloud. The cloud has separated its charges.

4. The electrons are clustered together at the bottom, which means they do induced charge separation on the neutral ground below, repelling the electrons on the ground. Until the attractive force is so high that the electrons surge down into the ground, by a path of least resistance.

a. This means the lightning is jagged, because dry air is a good insulator, which prevents lightning from reaching the ground. Moist air is a good conductor, and air with positive ions would also attract the lightning (and neutralize bits of it). So the lightning would avoid air with negative ions, and avoid dry air, so meaning its path would be jagged and not perfectly straight.

(diagram of steps below)

Lightning Rods

Lightning rods are pointed metal rods, which are grounded, and so stop the adverse effects of lightning. They attract lightning well because they are very tall too. They can work in one of two ways:

1. Because a cloud can induce a positive charge on anything below it, which includes the rod, so this repels airborne positive ions, sends them towards the thundercloud, which neutralizes some of the electron charge from the cloud

2. The positively charged rod attract the electrons of the lightning, and conduct those electrons safely down to the ground.

description

According to Ohm's Law, the potential difference at a point in a circuit is equivalent to the current times the resistance. This equation is written as V = I x R

Now that we know what resistance is: the impeding of the flow/speed of electrons, a reduction in current, there are certain factors, certain ways you can reduce/increase the resistance in a circuit.

1. Length of Wire:

The longer the wire,

2. Thickness of wire (or the smaller the inner radius)

3. Temperature