Science Term 1 Exam

Ion

An atom or molecule that has a net electrical charge

Density

A measure of which mass is packed into a specific volume

Fluids

Substances that flow. They can either be both liquid or gas.

Liquid/gas

Liquids have a definite volume and take the shape of the container in which they are in. Gas has no definite shape/volume and expands to fill up the container they are in and more.

Plasma

Another state of matter. It is a fourth state. It is a type of fluid. It is ionized gas superheated to strip electrons

Mass

Density x Volume

Density equation

Mass(gram)/Volume(mL)

Slurry

A mixture of solids and liquid. Slurry technology transports solids over liquid. E.g. paper you write with was once a slurry of wood pulp and water.

Hydroseeding

The process of spraying a slurry of seeds, fertilizer, and sawdust to plant difficult to reach areas. Mines use slurry technology to process minerals.

Froth flotation

A method in which mineral ores are converted to liquids.

Mineral ores

Natural rocks or sediments containing economically valuable minerals

Particle Theory

Warmer temperatures cause particles to move faster and farther apart while vibrating more. Particles are always moving and apart. Particle thoery explains that are matter is made of particles that are constantly moving/tiny with spacs between them and forces of attraction. Particle theory states that particles are attracted to each other, but particles in some substances may be more attracted to particles in another substance than their own.

Particle Theory Liquid

Particles in a liquid can overcome their attraction to each other and slide past each other. This is why liquids flow and take the shape of their containers.

Particle Theory Gas

Gas particles move so quickly and so far apart that they overcome almost all of their attraction for each other, meaning they spread out, filling all of the space in their containers.

Thermal Expansion and Contraction

When the temperature of a solid, liquid, or gas increases, the particles move faster/farther apart. As a result the substance expands. Thermal expansion is the increase in volume of a substance in response to an increase in its temperature. When the temperature decreases, the particles move slower and closer together, shrinking. Substances react to changes in temperature at their own rates.

Mass

Density x Volume

Volume

Mass/Density

Viscosity

A fluid’s resistance to flow.

High viscosity

Slower flow rate, e.g. honey

Low viscosity

Fast flow rate, e.g. water

Viscosity when more heat is added

The particles of a liquid start moving faster and farther apart, spreading out, causing less attraction between the particles, allowing them to move past each other easily, thus the flow rate increases and viscosity decreases.

Viscosity when the liquid gets cooler

Particles start moving slower and closer together, causing more attraction and making them move with difficulty past each other, thus the flow rate decreases and viscosity increases.

Factors that cause changes in viscosity/flow rate

The warmer the temperature, the lower the viscosity. Higher concentration increases the flow rate.

Viscosity and Flow Rate connection

The higher the viscosity, the slower the flow rate. This also connects to particle theory because particles that are attracted to each other creates more friction, preventing particles from moving at a fast pace, and so resulting in a low flow fate.

Flow Rate

Volume of mass of a fluid passing through a specific point of per unit of time. The speed of which a liquid flows.

Flow Rate Equation

Viscosity/Time

Buoyancy

The upwards force exerted by a fluid that opposes the weight of an immersed object, allowing it to float/rise.

To find buoyancy

Density of a fluid x volume of the object x Gravity

When does an object float?

An object floats when the upward buoyant force equals the downward force of the object’s weight. The object must displace a greater volume of the fluid. If the overall density of the object is less than the density of the fluid, the object will float. The denser the liquid, the higher the buoyancy.

Pressure/Pascals

The amount of force applied to an area. Measured in pascals(Pa). A pascal is equal to the force of 1N (newton) over an area of 1m². The more force to apply to an area, the greater the pressure.

Equation for pressure

Pa = N/m²

P=F/A

P = Pressure (Pa)

F = Force (N)

A = Area (M²)

P1=P2

F1/A2=F2/A1

A2=F2(A1)/F1

F1=F2(A1)/A2

F2=P1 x A2

Kilopascals

A pascal is a very small amount of pressure, so most scientists measure pressure in kilopascals (kPa). 1kPa=1000Pa

Pascal’s Law

When a force is applied to an enclosed fluid, the increase in pressure is transmitted equally to all parts of the fluid

Hydraulic v.s. Pneumatic Systems

Hydraulic systems use a liquid under pressure to transmit force/do work, Pneumatic systems use gases to transmit force/do work

Hydraulic systems

Multiplies force by applying force to small surfaces

• P = F small/A small = F large/ A large

  • A large/A small = F large/F small

• Hydraulic Brakes

• • The brake system multiplies the force so a person can stop a large car with only a light push on the brake pedal.

• Hydraulic Leak

• In order for pressure to be transmitted into fluid, the fluid must be confined. If the system is leaking, it won’t be confined.

• Pneumatic Systems

• A system that uses gas, usually air, under pressure to transmit a force

• In order for a gas to be put to work in a fluid system, it must be compressed

• E.g bus ramps/doors, dentist drill, nail gun, lungs, scuba gear, etc.

Water

70% of the Earth’s surface is covered by Water. There are two types of water. Salt and fresh.

Universal Solvent

• Solutions are mixtures of different particles called solutes and solvents

  • Solute is the one that dissolves, solvent is the one that it dissolves in

  • E.g. iced tea powder in water

• Water is a solvent that dissolves numerous - but not all - solutes. Therefore, it is known as the universal solvent.

  • Substances that dissolve in water: protein, minerals, sugar, salt, etc.

• Salt water

• 97% of the world’s water is in the oceans. Every litre of salt or ocean water has 33 grams of dissolved salts. 

• Most marine organisms have bodies with similar salt content

• Concentration of the dissolved salts in salt water is 3.5%

• Salinity is referred to how much salt is dissolved in water

• Fresh water

• 2.5% of water on Earth

• Less dense than salt water

• Low amounts of dissolved salts - less than 1%

• Contains solutes

  • Calcium carbonate, magnesium, Ferrous oxide,

• Different levels of these solutes, soft or hard

• Soft or Hard Water

• Hard water is water that contains a larger amount of dissolved minerals

  • E.g. calcium or magnesium

• Soft water is treated water in which the only ion is sodium

• Hard or Soft

  • Major differences

• Seen while doing household chores

  • Hard water is to blame for dingy looking clothing, dishes with spots and residue, and bathtubs with lots of film/soap scum

  • Even hair washed in hard water may feel sticky or seem dull

  • Hard water can take a toll on household appliances as well and use up more energy

  • The elements of hard water are to blame for all these negative factors as soap is less effective due to the magnesium and calcium. The lather is not as rich/bubbly

• Three states of water

• Mountain glaciers

• Ice sheets

• Liquid

  • Surface water

  • Underground water

• Gas

  • Water vapor

  • Steam from boiling water

• Water cycle

• Water is constantly on the move and changes states often

  • Liquid

  • Vapour (gas)

  • Solid

• No new water is created on Earth. It is always just changing states and cycling around the world.

• Process:

  • Evaporation

    • The sun heats liquid water in oceans, lakes, and rivers, turning it into water vapour that rises into the atmosphere

  • Transpiration

    • Plant releases water vapor from their leaves into the air, adding to the atmospheric moisture

  • Condensation

    • As warm, moist air rises, it cools, causing the water vapor to change back to tiny liquid water droplets, or ice crystals, forming clouds

  • Precipitation

    • When clouds become saturated, water falls back to Earth as rain, snow, sleet, or hail, depending on atmospheric temperature

  • Collection and Storage

  • Precipitation gathers in various stores

    • Surface Runoff

      • Water flows over land into rivers, streams, lakes, and eventually oceans

    • Infiltration

      • Water soaks into the soil and rock, becoming ground water, replenishing aquifers

    • Storage

      • Water is held in oceans, glaciers, ice caps, soil, and underground reservoirs

  • Sublimation

    • A less common process where ice and snow turn directly into water vapor, skipping the liquid phase.

  
  

Underground Water - Water table

• The ground beneath our feet is full of tiny holes, absorbing water like a sponge

• A water table is the layer of the earth where groundwater fills all the spaces in soil/rock, making it completely saturated

• The depth of a water table can defer depending on location, season, and how much rain has fallen

• A high water table means the ground is like a full sponge, it can’t soak up more water leading to increased surface runoff and even direct groundwater floating when it rises too high

• Effects on flooding in homes

• Saturated ground

  • When the water table rises too close to the surface, the ground above it becomes saturated, meaning it’s holding as much water as possible

• Reduced absorption

  • Once the ground is saturated, it can’t absorb much more water from rain/snow

  • Any additional precipitation has nowhere to soak in

• Increased runoff

  • Because the ground is already full, water stays on the surface, and flows downhill as runoff. This increased runoff can quickly overwhelm rivers, streams, and drainage systems

• Groundwater flooding

  • If the water table rises so high that it reaches the surface or even above the basement level of buildings, it can cause direct flooding from the ground itself

  • This is often seen as water seeping through the floors or walls of basements

• Sump pumps

• An electrical device that is typically installed in a pit below the basement floor, that automatically removes accumulated water to prevent flooding.

• Works by automatically pumping the water out of the pit and away from the foundation, usually discharging it into the yard or a nearby storm drain

How do they work? - sump pumps

1. A sump pit is a hole in the lowest part of the building, usually in a basement

2. A pump is installed in the sump pit, using power to move water out of the pit when it is triggered

3. The pump contains a float switch or pressure sensor, that detects water levels in the pit

4. Groundwater around the foundations of a home flows into the sump pit

5. When triggered, the pump pushed water away from the home’s foundation walls and to a storm sewer or grassy area

Sump Pumps for Sustainable Cities

• Climate change leads to more frequent and intense precipitation events

  • Sump pumps become more crucial than ever for adopting to these changes and minimizing their damaging effects on urban areas

• Preventing Groundwater Flooding

  • When the water table rises, the soil around the foundation becomes saturated, and water pressure pushes it towards and into basements

  • Sump pumps intercept this rising groundwater before it causes flooding inside buildings

• Reducing Pressure on Foundations

  • A high water table exerts a lot of pressure against basement walls and floors. 

  • Sump pumps prevent structural damage like cracks in the foundation by continuously moving water away from a building

• Protecting Property

  • By keeping basements dry, sump pumps protect personal belongings, prevent mold growth, and maintain a habitable living space, even when the water table is high.

• Tide Gauge

• Tide gauges help to measure how high or low the ocean water is

  • It’s like a ruler for the sea

• Scientists use tide gauges to sea if it’s a high tide or low tide, when the water falls or rises, and to learn about waves, storms, and floods

• Today, many tide gauges use technology to track more details about the water

  • Smart tide gauges are connected to the internet and can warn people about dangerous weather before they happen

    • E.g. flash floods

• Coastal Flooding

• When water from the ocean rises and covers land near the coast

• Climate change

• Makes things worse in two ways

• Warmer temperatures cause ice to melt, making the ocean rise higher

• Stronger storms caused by climate change also bring big waves and heavy rain

• Places near the ocean can then flood more regularly and more severely

  • People may need to evacuate to escape danger

Flood Alarms

• Tells people when there are unsafe conditions in their community

• Collect data from tide gauges like water level, time, and location to decide if an area is dangerous

• Can use notifications on people’s phones, flashing lights, and audio alarms to warn people that an area may be unsafe

• Enables early evacuation

• Minimizing health risks

Drinking Water

• The main causes of the global freshwater shortage highlighted in this video include the scarce amounts of freshwater, the climate change, over-extraction of underground water sources, as well as economic factors

• Only 1% of all water on Earth is safe to consume and does not contain salt. The population of this world is slowly increasing, which means we have to split this 1% of water between billions of people.

Climate Change affects on drinking water/human actions

• More droughts

• Reduced snowfall/rain needed to ensure our freshwater systems contain sufficient amounts of water

• In places like Mexico, the country’s population mainly relies on underground water sources. This means over-extraction of these water sources, leading to water “running out” in those places.

• Water is often treated as though it is worthless, with many people finding ways to waste it.

  • Due to the cheap price tags we put on these valuable liquids

• Human activities contribute to the freshwater shortage because of the high amounts of water we withdraw from underground sources, as well as the amount we tend to drink/use. 

  • Our shirts use water to make

  • Brushing our teeth

  • Washing our face

  • Flushing the toilet

    • All uses pounds of water

  • Climate change is caused by us

    • Greenhouse gases we produce

      • Decline in both the quality and amount of water be have

• The unequal access to water impacts communities socially, economically, and health-wise. 

• Conflicts breaking out due to the shortage of freshwater sources

• Economically affects those in poverty

  • If water prices were to increase, this would mean that certain people lacking this money would not be able to afford a liquid essential for their survival

    • Thus, since water is a vital source for our existence, raising the prices of water would not be the solution

• Certain countries do not have the resources to provide clean drinking water to everything

• Health risks such as reduced hygiene, and other risks depending on what is contaminated within the water

  • Gastrointestinal issues

    • E.g. diharrea

  • Vomiting

  • Cramps from the bacteria

  • Cancer

  • Organ damage

  • Neurological issues

  • Developmental problems