# 8th Grade Unit 1 Exam

12 Questions | Total Attempts: 89  Settings  This test will determine your proficiency level concerning your ability to evaluate experiments and conclusions.  You will also be evaluated on your understanding of magnets, electric-charge, electric circuits, mass, volume, and density. For some of the questions you will need to open the pdf file below this test box. GOOD LUCK!

• 1.
In one of the explorations done in class, the mass of a ball was measured before and after air was pumped into it.You observed that the ball had a greater mass after the air was pumped into it.  This observation provided evidence for which idea?
• A.

Mass and volume both describe the amount of material of something like air.

• B.

Mass is different from volume.

• C.

Air has volume.

• D.

Air has mass.

• E.

Density is the mass of a standard unit of volume.

• 2.
How is the interaction between two magnets different from an interaction between a magnet and a magnetic material?
• A.

Two magnets always attract each other, while a magnet and a magnetic material repel each other.

• B.

Two magnets may attract or repel each other, while a magnet and a magnetic material only attract each other.

• C.

Two magnets may attract or repel each other, while a magnet and a magnetic material only repel each other.

• D.

Both the two magnets and the magnet and magnetic material may attract or repel each other, so there is no difference.

• E.

Both the two magnets and the magnet and magnetic material always attract each other, so there is no difference.

• 3.
Which of the following statements is TRUE?
• A.

An electrically-charged object attracts objects that are not charged.

• B.

An electrically-charged object repels objects that are not charged.

• C.

An electrically-charged object always attracts other charged objects.

• D.

An electrically-charged object always repels other charged objects.

• E.

Electrically-charged objects have to be touching in order to interact with each other.

• 4.
You must read the pdf file before answering questions 4-8.The independent variable in this exploration was:
• A.

The number of batteries.

• B.

The amount of iron (number of nails).

• C.

The number of wires.

• D.

The compass deflection.

• E.

The closing of the switch.

• 5.
The dependent variable in this exploration was:
• A.

The number of batteries.

• B.

The amount of iron (number of nails).

• C.

The number of wires.

• D.

The compass deflection.

• E.

The closing of the switch.

• 6.
Do you believe that this experiment was a fair test?
• A.

No, because the students changed more than one variable on purpose.

• B.

No, because they did not measure the data correctly.

• C.

Yes, because they had one independent variable, one dependent variable, and everything else was controlled.

• D.

Yes, because the number of nails was held constant.

• E.

Yes, because the degrees of the compass were measured accurately.

• 7.
Juan's conclusion:I conclude that when the amount of iron increases, the strength of the electromagnet also increases.  My reason is that when the number of nails increased from one to two, the average compass deflection increased from 33 to 52 degrees.
• A.

Juan's conclusion is valid because his supporting reason was based on all of the available data as evidence.

• B.

Juan's conclusion is not valid because his reason is an opinion instead of being based on evidence from the exploration.

• C.

Juan's conclusion is not valid because his reason uses just part of the evidence instead of all the data.

• 8.
Marie's conclusion:I conclude that when the amount of iron increases, the strength of the electromagnet also increases.  My reason is that when you have more stuff, you will have a greater effect.  Therefore, the more iron you have, the greater is the compass deflection.
• A.

Marie's conclusion is valid because his supporting reason was based on all of the available data as evidence.

• B.

Marie's conclusion is not valid because his reason is an opinion instead of being based on evidence from the exploration.

• C.

Marie's conclusion is not valid because his reason uses just part of the evidence instead of all the data.

• 9.
What type of electrical circuit does this picture represent?
• A.

This is a series circuit because the bulbs are connected by wires.

• B.

This is a parallel circuit because if you unscrew one light bulb the others will stay on.

• C.

This is a series circuit because if you unscrew on light bulb the others will go out.

• D.

This is a parallel circuit because the wires create on large circle.

• 10.
What will happen to the top light bulb if you unscrew the center light bulb?
• A.

The top light bulb will remain lit because this is a parallel circuit and there will still be a complete circle.

• B.

The top light bulb will remain lit because this is a series circuit and there will still be a complete circle.

• C.

The top bulb will go out because this is a parallel circuit and the circuit will be broken.

• D.

The top bulb will go out because this is a series circuit and the circuit will be broken.

• 11.
Determine whether each of the following statements are true or false.A. mass can tell you exactly what something is.B. density can tell you exactly what something is.C. volume can tell you exactly what something is.
• A.

A. false; B. false; C. true

• B.

A. true; B. true, C. false

• C.

A. false; B. true; C. false

• D.

A. true; B. true; C. true

• E.

A. true; B. false; C. false

• 12.
Density is a measurement that tells you...?
• A.

How much matter is in a material.

• B.

How much matter is in a certain amount of space.

• C.

How much volume is present in a material.

• D.

How space an object occupies when you place it on a balance.

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