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 4 and 5, since they have the biggest difference
- Rows 1 and 3, since they show the smallest and a large result
Which two rows are a fair test of the number of coils alone, Kira?
- Rows 2 and 4, since both rows have 20 coils
- Rows 1 and 2, since only the coils change
- Rows 1 and 3, since row 3 has 20 coils and a core
- Rows 5 and 6, since both rows have 10 coils
Which two rows are a fair test of the number of batteries alone, Luz?
- Rows 1 and 6, since they show the biggest change
- 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
Which model of the field fits all four compass readings, Milo?
- Field lines run from the S pole to the N pole outside the magnet
- There is no field outside the magnet; the needle just points north
- Field lines go straight out from the magnet in each direction
- Lines leave the N pole, curve outside and enter the S pole
Pull on a paper clip (example data)
distance from the magnet (cm) pull (N) 1 8.0 2 2.0 4 0.5 Which statement does the force data support best, Pia?
- The pull is zero at any distance beyond 1 cm
- The pull is the same at each distance in the table
- Doubling the distance cuts the pull to a quarter
- The pull halves each time the distance doubles again
Poles found with a compass (example data)
piece left end right end whole magnet N S left half N S right half N S What does the table show about cutting a magnet, Ren?
- Each half keeps a single one of the two poles
- Each half has its own N pole and S pole
- Cutting a magnet destroys its poles
- The left half keeps the N and the right half keeps the S
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 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
- The coil stores magnetism after the battery is off