1.
Which of the following scenarios does not involve a chemical change?
Correct Answer
A. Melting ice
Explanation
Melting ice does not involve a chemical change because it is a physical process where the solid ice changes into liquid water due to an increase in temperature. No new substances are formed, and the composition of the ice remains the same.
2.
Your family is driving to Forks to attend Bella and Edward's wedding. If you live 800 miles from Forks, and your average driving speed is 60 mph, about how long will the drive take?
Correct Answer
A. 13 hours
Explanation
The correct answer is 13 hours. To calculate the time it will take to drive 800 miles at an average speed of 60 mph, we can use the formula: time = distance / speed. In this case, the distance is 800 miles and the speed is 60 mph. Dividing 800 by 60 gives us 13. Therefore, it will take approximately 13 hours to drive to Forks for Bella and Edward's wedding.
3.
How is a gas different from a liquid or solid?
Correct Answer
C. Both liquids and solids have definite volumes.
Explanation
The given answer is correct because both liquids and solids have definite volumes, meaning they have a fixed amount of space that they occupy. In contrast, gases do not have a definite volume as their particles are more spread out and can expand to fill the container they are in.
4.
While riding her bicycle, you little sister goes from a full stop to 9 m/s in 3 minutes. How fast is she accelerating?
Correct Answer
D. 0.05 m/s2
Explanation
The question asks for the acceleration of the little sister while riding her bicycle. The information given is that she goes from a full stop to a velocity of 9 m/s in 3 minutes. To find the acceleration, we use the formula: acceleration = (final velocity - initial velocity) / time. Plugging in the values, we get (9 m/s - 0 m/s) / 3 minutes = 3 m/s2. Therefore, the correct answer is 0.05 m/s2.
5.
Which quality affect an object's inertia?
Correct Answer
C. Its mass
Explanation
An object's inertia is affected by its mass. Inertia is the property of an object to resist changes in its motion. The greater the mass of an object, the greater its inertia. This means that objects with larger masses are more resistant to changes in their velocity or direction of motion. Therefore, the mass of an object is directly related to its inertia.
6.
Bella weighs 50 kg. The swing that she is sitting on weighs 2 kg. How much force will Edward need to push Bella on the swing to make Bella accelerate at 4 m/s2?
Correct Answer
D. 208 N
Explanation
To calculate the force needed to make Bella accelerate at 4 m/s², we can use Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. Bella's mass is given as 50 kg and the acceleration is given as 4 m/s². Multiplying these values together, we get 200 kg·m/s² or 200 N. However, we also need to consider the weight of the swing, which is 2 kg. Adding this weight to Bella's weight, we get a total mass of 52 kg. Multiplying this mass by the acceleration of 4 m/s², we get 208 kg·m/s² or 208 N. Therefore, Edward will need to apply a force of 208 N to make Bella accelerate at 4 m/s².
7.
When a car skids on ice, what kind of friction is acting on the wheels?
Correct Answer
C. Sliding friction
Explanation
When a car skids on ice, the kind of friction that is acting on the wheels is sliding friction. Sliding friction occurs when two surfaces slide against each other, and in this case, the wheels of the car are sliding on the icy surface. This type of friction is responsible for the lack of traction and control that occurs when a car skids on ice.
8.
When Emmet jumps up to make a basket, which force returns him to the ground?
Correct Answer
C. Gravity
Explanation
Gravity is the force that pulls objects towards the center of the Earth. When Emmet jumps up to make a basket, gravity is the force that brings him back down to the ground. Gravity acts on all objects and is responsible for keeping them grounded. In this case, gravity is the force that counteracts Emmet's upward motion and brings him back to the ground after jumping.
9.
Bella wants to know the best location in Charlie's house is best for growing African violets. She has three African violets. She puts one by her window, one by the kitchen window, and one next to Charlie's chair in the living room. Each plant has the same size pot and the same soil, and Bella gives each plant the same amount of water. In this experiment, what is the independent variable?
Correct Answer
C. Plant location
Explanation
The independent variable in this experiment is the plant location. This is because Bella is manipulating the location of the African violets by placing them in different areas of Charlie's house. The other variables - type of plant, type of soil, and amount of water - are kept constant throughout the experiment. By changing the plant location, Bella can observe and compare how each African violet responds to its surroundings, and determine which location is best for growing African violets.
10.
For Mr. Banner's class, Bella and Edward have to find out how temperature affects plant growth. Edward already knows the answer, but refuses to tell Bella. Bella thinks that warmer temperatures will promote faster plant growth. She stores four plants of the same type in locations with different temperatures. Edward reminds her to control all the other variables. Bella records the growth of each plant every week for two months. What is the next step that Bella should take?
Correct Answer
A. Analyze her data
Explanation
Bella should analyze her data next. After recording the growth of each plant every week for two months, she needs to analyze the data she has collected in order to draw conclusions and determine if her hypothesis that warmer temperatures promote faster plant growth is supported by the data. This step is crucial in the scientific method as it allows Bella to make sense of the information she has gathered and make informed decisions based on the results.
11.
Renee thinks her kindergarten students might learn to read faster if she uses a teaching method focused on the sounds different letters make. For two months, she teaches half the class using this method. She keeps teaching the other half of the class by reading aloud with them. What is the control of this study?
Correct Answer
C. The students Renee reads to
Explanation
The control of this study is "the students Renee reads to". This means that this group of students is not exposed to the teaching method focused on the sounds different letters make. By comparing the progress of the students who are taught using the teaching method with those who are read to, Renee can determine the effectiveness of the method in helping the students learn to read faster.
12.
The particles in motion around the nucleus of a carbon-12 atom are called _______.
Correct Answer
D. Electrons
Explanation
The particles in motion around the nucleus of a carbon-12 atom are called electrons. Electrons are negatively charged subatomic particles that orbit the nucleus in specific energy levels or shells. They play a crucial role in chemical bonding and determining the chemical properties of an atom. In the case of a carbon-12 atom, it contains six electrons, which occupy different energy levels around the nucleus.
13.
Carbon-14 differs from carbon-12 in terms of
Correct Answer
C. Number of neutrons
Explanation
Carbon-14 differs from carbon-12 in terms of the number of neutrons. Carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons. The atomic number, number of protons, and number of electrons remain the same for both carbon-12 and carbon-14.
14.
Which type of element is sodium?
Correct Answer
C. Alkali metal
Explanation
Sodium is classified as an alkali metal. Alkali metals are highly reactive, soft, and have low melting points. They are typically found in Group 1 of the periodic table. Sodium is a highly reactive metal that is commonly found in compounds such as sodium chloride (table salt). It is known for its ability to easily lose one electron, making it a strong reducing agent.
15.
Why do we see only one side of the moon?
Correct Answer
D. The rotation and orbit of the moon take the same amount of time.
Explanation
The correct answer is that the rotation and orbit of the moon take the same amount of time. This is known as synchronous rotation or tidal locking. Due to this phenomenon, the moon always shows the same face towards the Earth. As a result, we only see one side of the moon from Earth. The gravitational forces between the Earth and the moon have caused this synchronization over billions of years.
16.
Which of the following planets is closest to the earth?
Correct Answer
A. Mars
Explanation
Mars is the correct answer because it is the planet that is closest to Earth. While Mercury is the closest planet to the Sun, Mars is the planet that is closest to Earth in terms of distance. Saturn and Neptune are both much farther away from Earth compared to Mars.
17.
Before the 1500's, most people believed the center of the universe was ____________.
Correct Answer
B. Earth
Explanation
During the 1500's, the prevailing belief was that the Earth was the center of the universe. This concept, known as geocentrism, was widely accepted based on observations and interpretations of the natural world. It was not until later, with the development of heliocentrism by Nicolaus Copernicus and further advancements in astronomy, that it was proven that the sun is actually at the center of our solar system. This shift in understanding revolutionized our perception of the universe and our place within it.
18.
What causes a star to shine?
Correct Answer
A. Energy released from the fusion of hydrogen atoms
Explanation
Stars shine because of the energy released from the fusion of hydrogen atoms. In the core of a star, hydrogen atoms combine to form helium through a process called nuclear fusion. This fusion releases a tremendous amount of energy in the form of light and heat, causing the star to shine brightly. This process is what powers stars and allows them to emit light and heat into space.
19.
Before Jacob became a shapeshifter, he weighed 60 kg. He gained 40 kg. How many grams does he weigh now?
Correct Answer
A. 100,000 g
Explanation
Jacob weighed 60 kg before becoming a shapeshifter. He gained 40 kg, so his total weight now is 60 kg + 40 kg = 100 kg. To convert kg to grams, we multiply by 1000. Therefore, Jacob weighs 100 kg * 1000 g/kg = 100,000 g.
20.
Which of the following best describes the paths of the planets in our solar system?
Correct Answer
A. Elliptical
Explanation
The correct answer is elliptical. The paths of the planets in our solar system are best described as elliptical. This means that the planets do not follow a perfect circle, but rather an oval-shaped orbit around the sun. The shape of their orbits is influenced by the gravitational pull of the sun and other celestial bodies. This elliptical path allows the planets to have varying distances from the sun at different points in their orbit.
21.
Which of the following accurately discribes the shape of the earth?
Correct Answer
B. A spHere
Explanation
The correct answer is a sphere because the shape of the Earth is closest to that of a sphere. Although it is not a perfect sphere due to its slightly flattened poles and bulging equator, the Earth's overall shape closely resembles a sphere. This is supported by various scientific evidence, such as the Earth's gravitational field and the way it rotates. The spherical shape of the Earth allows for even distribution of gravity and explains phenomena like the curvature of the horizon and the way objects appear to sink below it.
22.
The density of a substance determines its ________________.
Correct Answer
B. Buoyancy
Explanation
The density of a substance determines its buoyancy. Density is defined as the mass of a substance per unit volume. When an object is placed in a fluid, it experiences an upward force called buoyancy. This force is determined by the density of the object relative to the density of the fluid. If the object is less dense than the fluid, it will float because the buoyant force is greater than the force of gravity. If the object is more dense than the fluid, it will sink because the buoyant force is less than the force of gravity. Therefore, the density of a substance directly affects its buoyancy.
23.
All of the following will sink in pure water except ________________.
Correct Answer
D. Olive oil
Explanation
Olive oil will not sink in pure water because it has a lower density than water. Density is the measure of how much mass is contained in a given volume. When an object is denser than the liquid it is placed in, it sinks, but if it is less dense, it floats. Since olive oil is less dense than water, it will float on top of the water rather than sinking.
24.
Which of the following stubstances is held together by physical rather than chemical means?
Correct Answer
B. Soil
Explanation
Soil is held together by physical rather than chemical means because it is composed of a mixture of minerals, organic matter, water, and air. The particles in soil are held together by physical forces such as gravity, friction, and cohesion. Unlike chemical bonds, these forces can be easily disrupted, allowing soil particles to be moved or separated.
25.
The periodic table can be divided into three basic categories. Which of the following is not one of the three major categories used on the periodic table?
Correct Answer
B. Alloys
Explanation
The periodic table is divided into three major categories: metals, nonmetals, and metalloids. Alloys, on the other hand, are not considered as one of the three major categories. Alloys are mixtures composed of two or more elements, at least one of which is a metal. While alloys are important in various fields, such as engineering and metallurgy, they are not classified as a separate category on the periodic table.
26.
Which of the following elements would you expect to best conduct heat and electricity?
Correct Answer
C. Copper
Explanation
Copper is expected to best conduct heat and electricity because it is a metal with a high electrical and thermal conductivity. Its atomic structure allows for the easy movement of electrons, which is essential for conducting both heat and electricity. In contrast, hydrogen, sodium, and carbon are not as efficient in conducting heat and electricity as copper. Hydrogen is a non-metal, sodium is a metal but not as conductive as copper, and carbon is a non-metal with low conductivity.
27.
The elements helium, neon, krypton and radon all belong to which of the following groups?
Correct Answer
D. The noble gas group
Explanation
Helium, neon, krypton, and radon are all noble gases. Noble gases are located in Group 18 of the periodic table and are known for their low reactivity and full outer electron shells. These elements have stable electron configurations, making them very unreactive and nonmetallic. Therefore, the correct answer is "the noble gas group".
28.
What term would you use to describe a substance composed of two or more elements that are chemically combined?
Correct Answer
C. A compound
Explanation
A compound is the correct term to describe a substance composed of two or more elements that are chemically combined. In a compound, the elements are bonded together in specific ratios and cannot be easily separated by physical means. This is different from a mixture, where the elements are not chemically combined and can be separated by physical means. A solution refers to a homogeneous mixture, while an element is a pure substance composed of only one type of atom. Therefore, the term "a compound" best describes a substance composed of two or more elements that are chemically combined.
29.
How are saltwater and soil different?
Correct Answer
D. Soil is a mixture; saltwater is not.
Explanation
Saltwater and soil are different because soil is a mixture, while saltwater is not. Soil is composed of various organic and inorganic materials, such as minerals, organic matter, water, and air, which are mixed together. On the other hand, saltwater is a solution where salt is dissolved in water. It is not a mixture as the salt particles are evenly distributed throughout the water, forming a homogeneous solution.
30.
The atoms of any one specific element are always ________________.
Correct Answer
B. Alike
Explanation
The atoms of any one specific element are always alike. This means that all atoms of a particular element have the same number of protons in their nucleus and the same number of electrons surrounding the nucleus. This similarity in atomic structure is what defines an element and allows scientists to classify and identify different elements.