*Multiple Choice*
Which statement about electric charges is correct?
A. Like charges attract.
B. Opposite charges attract.
C. Opposite charges always repel.
D. Charges cannot interact without touching.
Answer: B β Opposite charges attract.
*Fill in the Blank*
Gravity is an __________ force because objects do not have to touch for it to act.
NAME THE FORCE.
Answer: Non-contact
*Multiple Choice:*
βοΈ How does thermal energy from the Sun travel through space to Earth?
A. Conduction
B. Convection
C. Radiation
D. Evaporation
Answer: C β Radiation
*Vocabulary Challenge!*
What are the TWO main types of pure substances?
Answer: Elements and compounds
*Physical or Chemical Property??*
A scientist records the melting point, boiling point, and density of a substance. Are these physical or chemical properties?
Answer: Physical properties!
*Fill in the Blank:*
An object becomes electrically charged when it gains or loses __________.
Electrons!
*Identify It!*
What device uses electric current to create a magnetic field?
Use the picture as a reference.
π ββββββ°β°β°β°βββββ
π©
πππ
Answer: An electromagnet
*Name It, Identify It!*
Name AND Define the [3] methods of Heat Transfer. If you answer one incorrectly, you DON'T get the points!
Answer:
1. Conduction: physical touch/direct contact
2. Convection: occurs in liquid & gases/circulation particle movement (hot air rises - cool air sinks)
3. Radiation: without physical touch "feel the heat!"
*Identify It!*
Salt completely dissolves in water and appears evenly distributed throughout the sample. What type of mixture is it?
Answer: Homogeneous mixture
*Vocabulary Challenge!*
The amount of mass in a certain volume is called __________.
Answer: Density!
*Explain It!π Maya rubs a balloon against her hair. Her hair begins to stand up and is attracted to the balloon. What force is responsible?
Answer: Static Electricity!
Your hair stands up because rubbing a balloon creates static electricity through friction. Rubbing the balloon on your hair moves tiny invisible particles called electrons from your hair to the balloon. Electrons have a negative charge. The balloon becomes negatively charged, and your hair is left with a positive charge.
*Cause & Effect!*
Why does wrapping current-carrying wire around an iron nail allow the nail to attract paper clips?
Answer: Electric current through the wire produces a magnetic field, magnetizing the iron core. The number of wire coils/turns can either increase or decrease the strength of the electromagnet.
*Complete the Energy Transformation!*
Complete the transformation for a lamp:
Electrical Energy β __________ Energy + Thermal Energy
Answer: Light/radiant energy
*Picture Scenario!*
Classify this sample:
π₯ + π« + π + π₯¨
TRAIL MIX
A.Pure Substance
B. Compound
C. Homogeneous mixture
D. Heterogeneous mixture
Answer: D β Heterogeneous mixture
*Particle Picture!*
Identify the state of matter in this picture and explain WHY this is the appropriate answer:
β β
β
β
β
Answer: Gas because particles are far apart and able to move freely and rapidly.
*Picture It!*
N S
[π§²] β β [π§²]
According to the scientific evidence you've learning about magnetic poles, explain what is happening in this picture.
Answer: The opposite magnetic poles attract. Like poles always repel.
*Lab Connection!*
During an electromagnet experiment, you wrap wire around a nail 15 times and then 35 times. The 35-coil electromagnet picks up more paper clips. What variable increased?
Answer: Number of wire coils/turns.
*Particle Movement:*
A solid object is heated. What generally happens to the motion of its particles?
Answer: The particles gain thermal energy and vibrate/move faster.
*Particle Model:*
What does this model MOST likely represent and WHY?
π΅βπ΄ π΅βπ΄ π΅βπ΄
*hint: Think about elements, compounds, and pure substances when explaining your answer!
Answer: A compound, because different types of atoms (or elements) are chemically bonded together.
*Analyze It - - Identify It*
A ________ is a state of matter with a definite volume but no definite shape. It is less organized, but particles are relatively close together, and able to move and slide past each other.
*Hint: Particle Model*
β β β
β β
β β β
Answer: Liquid(s)!
*Analyze It!*
A compass needle changes direction when a magnet is brought near it. What does this provide evidence for in regards to fields and forces?
Answer: A magnetic field exists around the magnet. Magnetic forces can act at a distance through magnetic fields. A magnet can attract certain objects without touching them. The region around the magnet is referred to as the magnetic field.
*Name It!*
Name the [3] parts AND describe the roles of the parts to a building a simple electromagnet.
Answer:
1. Electrical Source (battery or light bulb) - provides energy to the current.
2. Insulated Wire - The current travels through the wire.
3. Metal Core (Iron Nail) - Strengthens the magnetic field produced by the current.
*Transformation Challenge!*
π A battery-powered speaker is turned on. Which transformation BEST describes the system?
*hint: There are 3 different transformations!
Answer: Chemical β electrical β sound
*Explain YOUR Reasoning!*
A student says, "Salt water is a compound because salt and water are together." Explain the error in this statement.
Answer: Salt water is a mixture because the substances are physically combined and did NOT form a new pure substance, and they can be physically separated.
*Analyze It - - Explain It!*
A student heats a solid until it becomes a liquid and then continues heating it until it becomes a gas. Describe what happens to the particles as thermal energy is added.
Answer: As thermal energy increases, particle motion increases. In the solid, particles mainly vibrate in fixed positions. As the substance melts, particles gain enough energy to move past one another as a liquid. With additional energy, particles eventually spread much farther apart and move freely as a gas.