Magnets, magnetic fields and electromagnets
Grade 8 Science Worksheet
Circle the best answer, or write your answer on the line.
Read this first
Teacher's electromagnet test (example data)
coils batteries paper clips lifted 10 1 4 20 1 8 10 2 8 Each change multiplies the clips lifted. How many clips would Ari's electromagnet lift with 20 coils and 2 batteries together?
Each change multiplies the clips lifted. How many clips would Bo's electromagnet lift with 30 coils and 2 batteries together?
Each change multiplies the clips lifted. How many clips would the electromagnet lift with 20 coils and 3 batteries together, Esme?
Which two rows are a fair test of the iron core alone, Jun?
- Rows 2 and 3, since only the core changes
- Rows 3 and 4, since both have an iron nail
- Rows 1 and 3, since they show the smallest and a large result
- Rows 4 and 5, since they have the biggest difference
Which two rows are a fair test of the number of coils alone, Kira?
- Rows 5 and 6, since both rows have 10 coils
- Rows 1 and 3, since row 3 has 20 coils and a core
- Rows 1 and 2, since only the coils change
- Rows 2 and 4, since both rows have 20 coils
Which two rows are a fair test of the number of batteries alone, Luz?
- Rows 4 and 5, since row 4 has 2 batteries in it
- Rows 2 and 3, since both rows have 1 battery
- Rows 5 and 6, since only the batteries change
- Rows 1 and 6, since they show the biggest change
Which model of the field fits all four compass readings, Milo?
- Lines leave the N pole, curve outside and enter the S pole
- There is no field outside the magnet; the needle just points north
- Field lines go straight out from the magnet in each direction
- Field lines run from the S pole to the N pole outside the magnet
Which model fits all three compass readings between the two magnets, Noah?
- The lines run from one magnet across to the other, as if N faced S
- Each N pole pushes its lines away; the field is near zero in the middle
- The magnets do not affect each other, so the needle ignores them both
- Each magnet's field stops at that magnet's own end, without reaching the gap
Far from magnets, a compass's north end points toward Earth's northern magnetic pole. What kind of magnet pole must it be, Tala?
- An N pole, since the needle's north end points to it
- It acts like an S pole, since unlike poles attract
- An N pole, since like poles attract each other
- Neither, since Earth is not a magnet and has no poles
Electromagnet with an iron nail (example data)
battery connected paper clips lifted compass needle moves yes 14 yes no 0 no What does the table show about the electromagnet's field, Zee?
- The coil stores magnetism after the battery is off
- The nail is a permanent magnet whatever the battery does
- The field depends on the current; with it off, clips drop
- The battery itself is the magnet that lifts the clips