Experiments

Question 1

Current and voltage relationship in a resistor

Answer 1

Set up a series circuit
Keep resistance constant
Starts at the lowest voltage (2v)
Measure current in resistor using ammeter
Measure voltage across the resistor is using a volt meter
Take three readings of each and calculate voltage
Repeat previous steps increasing voltage by 2v up until 12v

Improving accuracy – increased voltage by smaller amounts to get more results

Question 2

Calculating density

Answer 2

Measured mass of object using scales
Fill a displacement can with water so the waterline just touches the spout
Place object into displacement can
Collect the water spills out of can using a measuring cylinder
The volume of the water spilt equals volume of object

Improving accuracy – put objects in water using string to avoid unnecessary displacement

Question 3

Calculating the specific heat capacity of water

Answer 3

Set up a series circuit with the battery, and immersion heater, an ammeter and a volt meter
Fill a polystyrene cup with water and measure the mass using scales
Submerge immersion heater into water and record start temp
Switch on circuits, time five minutes to allow water to heat
After five minutes, record final temp voltage and current
Calculate power, energy and specific heat capacity

Improving accuracy – put lid on, use insulated cop

Question 4

Force and extension relationship in a spring

Answer 4

Measure unstretched length of spring
Hang spring from clamp stand with a ruler next to it
Suspend a mass on the end of the spring so it stretches
Measure new length of spring using a ruler
Calculate extension by substracting the original length from the new length
Take masses off to check that spring goes back to original length
Repeat previous steps, adding more mass until it doesn’t go back to original length
Find force using spring constant X extension

Improving accuracy – add smaller masses, take maths off and check length three times