PAPER 1 REQUIRED PRACTICALS

Question 1

SHC

Answer 1

place beaker on a balance and press zero
add oil to the beaker and record the mass of the oil
place a thermometer and an immersion heater in the oil
wrap the beaker in insulating foam tp reduce thermal energy transfer
connect a joulemeter to the immersion heater
time for 30 minutes
read the number of joules of energy that passed into the immersion heater
read final temp of oil
use equation change in thermal temp/ mass times temp change

Question 2

why there might be errors with shc practical

Answer 2

thermal energy passing out of the beaker into the air– so use a thermal insulator with lower thermal conductivity
not all thermal energy passing into the oil— make sure the immersion heater is fully submerged
incorrect reading on the thermometer— use a temperature probe

Question 3

thermal insulator practical

Answer 3

cover beaker with insulating material
then use kettle to boil water
next transfer a known volume of water to the beaker
then use cardboard as a lid for the beaker- the lid has a hole for the thermometer
record starting temp
start stopwatch and record the temp every three minutes for 15 minutes
repeat for different insulating materials when doing repeats has to be same volume of water and has to be the same mass

Question 4

IV For thermal insulator practical

Answer 4

material

thickness

Question 5

dv for TI practical

Answer 5

temp

Question 6

cv for TI practical

Answer 6

volume of water
container
time

Question 7

practical for thickness of insulator

Answer 7

same experiment
this time repeat experiment this time wrap two layers of newspaper around the beaker
then repeat using four layers then six layers

Question 8

results of TI prac

Answer 8

the cooling curves plotted for diff materials can be used to compare their effectiveness as thermal insulators

the cooling curves for different thickness should show that the thicker the material the slower the rate of heat loss from the beaker

Question 9

errors in TI practical

Answer 9

heat loss through the top/ bottom of the beaker
different starting temp of water at room temp would cause different rates of heat loss
random error using thermometer

Question 10

how to reduce errors TI practical

Answer 10

stand beaker on a heat proof mat and cardboard/plastic lid with hole in for thermometer
try to ensure same starting temp of water
re[eat experiment calculate an average

Question 11

RESISTAMCE rp

Answer 11

for length of a wire
connect circuit with crocodile clips 10 cm apart on a long wire
measure and record current and voltage
repeat at 10cm intervals
calculate resistance for each length 
plot graph of resistance against length 

for combination of resistors- connect circuit with resistors in series
measure current and voltage
calculate resistance
connect ciruit with resitors in parallel
measure current and voltage

Question 12

errors resistnace practical

Answer 12

zero error is a reading on a measuring instrument when the value should be zero
this is a systematic error
with resistance we need to subtract the zero error from all our readings

if the temp of wire increases then the resistance will alo increase- so use a low potential difference this will keep the current low, reducing any heating in the wire
only turn on current between readings

Question 13

results for resistance practical

Answer 13

the resistance of a wire is directly proportional to the length of the wire

combo of resistors- the total resistance of a circuit with resistors in parallel is less than the total resistance of the same resistors connected in series

Question 14

scientific explanation for length of a wire

Answer 14

as the length of the wire is increased, there is a greater distance for electrons to travel with no more energy supplied. this results in less current flowing (higher resistance)

Question 15

current/ pd characteristics resistor

Answer 15

resistor- battery is connected by wires to a resistor
the resistor is in series with an ammeter and a variable resistor
voltmeter in parallel
use voltmeter to calculate potential difference
then use ammeter to record current through a resistor
record this on a table
adjust the variable resisitor and record the new reading on the voltmeter and ammeter
do several times to get range of readings
next switch direction of the battery this means pd is reversed(negative readings
continu taking several readings of pd and current

current is directly proportional to pd even when switched

Question 16

current/ pd characteristics filament lamp

Answer 16

repeat using filament lamp
adjust the variable resistor and read both pd and current
do this for a range of values with battery in forward and reverse direction

when temp increases resistance increases

Question 17

current/ pd characteristics diode

Answer 17

add extra resistor to circuit to keep current low and protect the diode
repeat using diode
adjust the variable resistor and read both pd and current
do this for a range of values with battery in forward and reverse direction

when pd is reversed we get no current because in reverse direction we get no current because in reverse direction diode has high resistance

Question 18

improvemnets to characteristic prac

Answer 18

use a milliammeter instesad of ammeter

repeat and cslculate average

Question 19

density prac

Answer 19

for regular objects
use balance to measure the mass
use a ruler to work out the length of the sides of the object - this will get you the volume
use eq density= mass/volume

for irregular objects-
find mass of object using a balance
fill eureka can with water
place the object in water. this will cause the water to be displaced and flow out of the can through the spout
measure the volume of water displaced. this volume is the same volume as the object
calculate density=mass/volume

Question 20

what are the risk of the dens orac

Answer 20

water spillages

Question 21

errors for the dens prac

Answer 21

random error using ruler, balance, measuring cylinder
displaced water might not all be collected
cylinder may already have drops of liquid in it already

Question 22

reducing error density prac

Answer 22

repeat investigation and calculate average
place object in water carefully,
leave measuring cylinder in position until water has stopped dripping out
ensure measuring cylinder is empty