Unit 1
Why can alien species be harmful to non-native areas? (2 K/U)
Whether alien species are intentionally introduced to non-native areas or not, they can potentially prove to be dangerous for the ecosystem of the surrounding areas. They can intrude the areas of native species deprive them of shelter, food, and other necessities for a native species. They disrupt the ecological balance (equilibrium) by reproducing too fast and using up all the resources while leaving none for the native areas. They can cause competition and ultimately extinction for the native species by inducing a lack of food, shelter, etc.
Why are ionic compounds made up of a metal and a non-metal? (2 K/U)
Ionic compounds are made by the loss and gain of a two or more elements. In order to ensure a perfect combination, a metal and one or more non-metals are used since one looses the electron and the other gains it. It is easier for a metal to loose electrons and it is easier for non-metal to gain electrons to form a strong bond. This allows the ions to have complete shells thus forming ionic compounds.
How can we confirm that the Milky Way galaxy is a spiral galaxy? (2 K/U)
Spiral galaxies have a bulge in the middle which allowed researchers to ensure that the Milky Way galaxy is a spiral galaxy. Harlow shapely put together different clues to conclude that Milky Way is a spiral galaxy. He studied the star patterns and noticed that the open clusters are around the Milky Way and the globular clusters are in a spherical shape in the centre. Using the radio waves between stars the diameter of the galaxy has been confirmed leading to the determination of Milky Way being disk-like. The final determination of the shape came from infrared radiation that proved the existence of the bulge leading to the shape of a spiral.
Why can't a person use water when dealing with electricity, even though 'pure water is a good insulator'? (2 K/U)
As stated in the book that pure water is a good insulator but its also called the universal solvent which means that it is extremely easy for most substances to mix/dissolve in water. Even through rain, water isn't pure and it contains salt and other substances in it too. Although pure water is a good insulator, the factor of a water solution makes it a good conductor as well. In fact, tap water and/or salt water is quite good at conducting electricity. This is the reason for why it is necessary to be cautious around devices when water is nearby.
The polar region ecosystems have been very severely affected by some extremely harmful human actions, such as using fossil fuels. Why is it important to save these animals? Suggest 3 activities that you may perform to save the valuable animals of arctic and antarctic region. (2 C)
All living things play a role in this world and each every species has a unique part that is connected to every ecosystem like a chain. Polar bears and other arctic animals are also exteremly important to this world as they regulate populations and help the ecosystem in many ways. Many arctic animals like the beluga whale or polar bear are at the top of the food chain, which means that they regulate the lower population by hunting/eating the other lower living things. If they are not saved, they prey's population may increase rapidly which could lead to the extinction of the rapid growing population's food. Everything is linked so the extinction of one species leads to severe amount of damage. For humans, these arctic animals hold cultural/traditional and economical importance as their fur can be traded and the Inuit and other tribes love them.
These beautiful animals can be saved by...
1) Convincing communities to avoid the use of fossil fuels by using renewable energy sources (for example, solar panels.)
2) Avoid wasting food, water, etc.
3) Voice your opinion and debate this issue.
Draw a Bohr-Rutherford diagram for an ionic compound of Magnesium Sulfide (MgS). (2 C)
Make a creative leaflet to describe a few components (that are used to identify and predict stars and cycles) in the Hertzsprung-Russell Diagram (2 C).
Create a combination of a parallel circuit and a series circuits using the website... "https://phet.colorado.edu/sims/html/circuit-construction-kit-dc/latest/circuit-construction-kit-dc_en.html"
Represent the circuit in symbols and real things. (2 C)
Apply your knowledge to determine the units of energy at each trophic level in the food chain having the information that the trophic efficiency at each level is 14%. (2 A)
Primary producers - water lily: 10,735 energy units
Primary consumers - goldfish: ?
Secondary consumers- blob catfish: ?
Tertiary consumers- shark: ?
Trophic efficiency: 14%
Primary producers - water lily: 10,735 energy units
Primary consumers - goldfish: (10,735 × 14)% = 1,502.9 energy units
Secondary consumers- blob catfish: (1,502.9 × 14)% = 210.406 energy units
Tertiary consumers- shark: (210.406 × 14)% = 29.45684 energy units
A messenger from an unknown mysterious group has emailed you, providing an explanation for the terrible massacre in Korea. Here's what part of it reads:
"It's absolutely disheartening to hear that you have blamed us for intentionally killing thousands of people with a nuclear bomb in Korea, even though we would never dare to think about doing such a heartless act. Allow us to clear the truth: one of our agents truthfully says that he saw the Main Terrorists League drop an opened bottle of Krypton in the main lake creating a violent chemical reaction while burning the people around it."
Why should you be skeptical about this claim? (2 A)
Krypton is in the group of noble gases therefore it is a non-reactive element that cannot create an explosion in water as it doesn't react violently with almost anything. Specifically, being a gas, krypton would have escaped in the air as the dropped bottle was 'opened' so even if it was reactive, it would just mostly escape in this air. But, krypton is a non-reactive noble gas so this mysterious group its hiding the truth because of the fear of being questioned and exposed.
Would the surrounding galaxies appear to be shrinking when looked from the Milky Way? Why or why not? Provide evidence in your answer. (2 A)
When an object moves away from the observer, it is red-shifted and it appears to be shrinking- so when the galaxies are looked upon from earth, they would appear to be shrinking because of the Big Bang theory. Since the Big Bang (the reason for the creation of the universe) occurred, the universe has been expanding at an accelerating rate. This forces mostly every celestial body to move away from each other. The book also states that Edwin Hubble and Milton L. Humason "discovered the speed of a galaxy, which is determined from its redshift, is proportional to the distance of the galaxy from Earth." The shrinking galaxies also provide an evidence for the Big Bang Theory.
A medium sized metal Santa seat has many bulbs that light up to appeal children. In the mechanism, it has a resistance of 96Ω while it operates on 4 cells of 3 volts each in a series. Calculate the current of this Santa seat. (2 A)
Ohm's law states...
V=IR or R=V/I
So to calculate resistance, it is....I=V/R
- Volt/Potential difference =
4 x 3 = 12 (sum of volts in each cell in a series)
- Resistance = 96Ω
Substitute R=96 and V=12 in the equation:
I=V/R
I = 12/96
I = 0.125 Amperes (A)
Therefore, the current of the Sana'a seat is 0.125A.
Purple loosestrife, an invasive species, came to Canada and disrupted ecosystems extremely. Explain how this attractive flower may have disturbed the ecosystem and suggest two ways to eradicate this extremely harmful species. (2 T/I)
The flower may have grown in a fertile area so it may have grown to be a competitor for the native plants. It can use all resources, such as food, water, sunlight and space/area - causing deprivation for the native plants that will slowly start to reduce in quantity with the purple loosestrife striving wonderfully. If not taken care of early, some native plants may get endangered with the purple loosestrife taking over their habitats and potentially causing extinction. In order to eradicate this dangerous species, biocontrol and/or chemicals may be needed to control/eliminate this species completely. Another strong species of flower or a wild herbivore may be introduced in the purple loosestrife infested areas to destroy these plants and stop their growth. If that doesn't work, then the chemicals may be used to destroy the seedling or spray the soil; thus stopping the growth of purple loosestrife.
An empty tube has the mass of 47.8g. It is filled completely to the top with seawater and the mass has been recalculated to be 138.44. The tube was dried and cleaned thoroughly and refilled with an unknown substance. The new mass is found to be 117.32g. (2 T/I)
Use the following link to answer the question above:https://jamboard.google.com/d/1coypQ8fB-ZUe-CWbUaN1OBYgwCsNEA7nAALwqFGEERI/edit?usp=sharing
•Seawater:
-mass: 138.44 - 47.8g = 90.64
-Density of seawater: 1.03
D = m/v
v = m/D
v = 90.64/1.03
v = 88 cm^3
•Unknown Substance:
-mass: 117.32g - 47.8g = 69.52
-volume: 88 cm^3
D=m/V
D = 69.52/88
D = 0.79 g/cm3
The unknown substance is ethyl alcohol.
How can studying space objects in different wavelengths be helpful for researchers and astronomers to understand the components in space? (2 T/I)
Different wavelengths reveal different kinds of information about celestial bodies, so when looked from different wavelengths scientists can get a lot more information than when looked from only one wavelength. The following is advantage provided by each wavelength feature:
1) Visible light - gives an idea of how it looks visibly, close up. For example, the location of comet impacts.
2) Ultraviolet radiation - auroras or the location of the planets' poles can be viewed using this radiation.
3) Infrared radiation - reveals the atmospheric composition of a planet and gives the height of clouds and atmosphere.
4) Radio wave - two types of components can be distinguished using this radiation: that a celestial body gives off radio waves and the part that absorbs this radiation in the celestial object.
Using different types of radiation is very helpful to astronomers (to check if landing is safe) and researchers to predict and understand/explain the components in space.
If 4 circuits containing are identical in terms of loads, temperature, cells, and switches, but are different in following ways...
Circuit 1: A 2m copper wire ---> 0.2 diameter
Circuit 2: A 2m aluminum wire ----> 0.1 diameter
Circuit 3: A 1m silver wire ---> 0.2 diameter
Circuit 4: A 5m copper wire ----> 0.04 diameter
then, how will the resistance change? Rate the resistance from lowest to highest. (2 T/I)
Length, material and diameter should be taken into consideration with measuring the resistance. So, circuit 3 has the shortest wire, the best conductor (silver) and a high diameter so it has the least resistance. Circuit 1 has a short wire, a good conductor, and a high diameter so it has the second least resistance. For circuit 2, aluminum is not the best conductor and it has a short diameter while having a medium length so it has the second most resistance. Lastly, although copper is a good conductor, the wire is lengthy and short in diameter so it will have the most resistance. The rating will be 3,1,2,4 in terms of resistance.