Investigating how the viscosity of oil varies with temperature

Equipment

pipette with hole in bulb and an upper and lower mark made on the pipette stem
blu-tak
250 cm³ conical flask
test tube
vegetable oil
thermometer
stopwatch

Method

1. Half fill the conical flask with hot water
2. Half fill the test tube with vegetable oil and place the test tube into the conical flask of hot water
3. Place the thermometer into the test tube
4. Wait for the temperature of the oil to reach the same temperature as the water
5. Record the temperature of the oil
6. Using blu-tak to block the hole in the bulb, fill the pipette to the upper mark
7. Lift the pipette out of the oil (but keep it inside the test tube) and time how long it takes for the oil to drain down to the lower mark when the hole in the bulb is uncovered
8. Repeat steps 5-7 for different (cooler) temperatures of oil.

Risk assessment

hazard	risk	probability	mitigation
glassware	cuts	low	place glassware in centre of desk
hot oil	burns	low	handle hot oil with care; run burns under cold water
slippery oil	slips and falls	low	immediately clean up spilled oil; inform others of spill

There are no other significant risks.

Images

Investigating how the viscosity of oil varies with temperature

Equipment

pipette with hole in bulb and an upper and lower mark made on the pipette stem
250 cm³ conical flask
test tube
vegetable oil
thermometer
stopwatch

Method

1. Half fill the conical flask with hot water
2. Half fill the test tube with vegetable oil and place the test tube into the conical flask of hot water
3. Place the thermometer into the test tube
4. Wait for the temperature of the oil to reach the same temperature as the water
5. Record the temperature of the oil
6. Cover the hole in the pipette bulb and fill the pipette to the upper mark
7. Lift the pipette out of the oil (but keep it inside the test tube) and time how long it takes for the oil to drain down to the lower mark when the hole in the bulb is uncovered
8. Repeat steps 5-7 for different (cooler) temperatures of oil.

Risk assessment

hazard	risk	probability	mitigation
glassware	cuts	low	place glassware in centre of desk
hot oil	burns	low	handle hot oil with care; run burns under cold water

There are no other significant risks.

Images

<awaiting images>

Measuring the force needed to overcome friction for a wooden block

Equipment

wooden block with affixed curtain hook and mass hanger
4 x 100 g masses
500 g top pan balance
0-10 N newton meter
board pen

Method

1. Zero the newton meter by turning the adjustment screw.
2. Use the top pan balance to measure the mass of the wooden block. Note down the mass.
3. On the desk draw around the wooden block to ensure the block starts from the same place each time.
4. Place the block in the rectangle on the desk.
5. Attach the newton meter to the curtain hook.
6. Very slowly increase the force used to pull the newton meter away from the block.
7. Note the force at which the block first slips across the desk.
8. Repeat steps 4-7 a further two times and calculate the average force required to make the block slip.
9. Add a 100 g mass to the wooden block. Write down the new mass of the block.
10. Repeat steps 4-8 for this new mass of the block. Keep adding masses and repeating until you have five rows of data.

Note:

• to convert a mass in kg to a weight in N multiply by 10
• to convert a mass in g to a weight in N divide by 100.

Risk assessment

hazard	risk	probability	mitigation
heavy equipment	crush injuries	low	keep equipment in centre of desk

There are no other significant risks.

Images

<awaiting images>

Temperature change of beaker of water

Equipment

kettle
stopwatch
thermometer
100 ml pyrex beaker
100 ml measuring cylinder
heatproof mat

Method

1. Fill the kettle and boil the water
2. Pour 50 ml of boiling water into the beaker and stand it on the heatproof mat
3. Start the stopwatch and note the starting temperature of the water
4. After three minutes stop the stopwatch and note the final temperature of the water
5. Leave the hot water in the beaker
6. Repeat steps 3-5 a further four times
7. For each row of data calculate the temperature change

Risk assessment

hazard	risk	probability	mitigation
kettle	electrocution	low	keep lead away from water; mop up any spills; keep hands dry
hot water	burns	low	keep hot water in centre of desk; use protective clothing
glassware	cuts	low	handle glassware with care; quickly tidy up any broken glass

Images

<awaiting images>

Time period of an oscillating spring

Equipment

stand

bosses x 3

clamps x 3

G-clamp

metre rule

light spring

700 g of slotted masses including hanger

stopwatch

Method

1. Use the G-clamp to secure the base of the stand to a desk.
2. Fix a metre rule in the vertical position using two of the bosses and clamps.
3. Using the other boss and clamp, position a spring near to the top of the stand so the spring hangs vertically down in front of the metre rule.
4. Adjust the mass of the hanger to 700 g, and suspend it from the spring.
5. Remove the 700 g mass to ensure that the spring has not deformed.
6. Suspend the mass from the spring and note the approximate position of the mass once at rest.
7. Ensure that the mass can oscillate up and down without touching the metre rule.
8. Pull the mass down by 3 cm and then release.
9. Once the mass is oscillating, time how long it takes for 10 complete oscillations.
10. Repeat steps 6-8 twice more and take an average.
11. Repeat steps 6-9 for masses of 600 g, 500 g, 400 g, and 300 g.

Risk assessment

hazard	risk	probability	mitigation
heavy equipment	crush injuries	low	position masses away from table edge; use G-clamp to secure stand
spring	sharp wires	low	don't overload the light spring; wear goggles

Images

Studying the effect of intensity of exercise on fatigue

Equipment

stopwatch

Method

1. Perform some dynamic warm-up exercises on your non-dominant hand ('hand') to reduce the risk of muscle strain
2. Stretch your hand into the air above your head so that your arm is fully extended
3. Clench and unclench your hand at a frequency of one clench every two seconds
4. Record the time it takes for your hand to become completely fatigued - this is the point where it is too painful to continue
5. Rest the hand for two minutes
6. Repeat steps 2-5 but each time increase the frequency of clenching from one clench every two seconds to five clenches every two seconds in intervals of one clench every two seconds
7. Rest the hand for five minutes but each minute perform some static warm-down stretches on the hand
8. Repeat the entire process, steps 1-7, another two times to enable an average to be calculated
9. Perform some static warm-down stretches on the hand

Safety

The subject may develop muscle strain, so it is important that the warm-up and warm-down procedure is followed.

There are no other significant risks.

LDR response to variations in light intensity

Equipment

LDR
Multimeter
Connecting leads
Crocodile clips
Desk lamp
Metre rule
Blu-Tak

Method

1. Connect the LDR to the multimeter using crocodile clips and connecting leads.
2. Set the multimeter to read ohms.
3. Set the LDR up so it is 10 cm from the lamp. Ensure the lamp and the ruler are fixed in place to reduce errors in measuring distance.
4. Switch on the lamp and use the multimeter to record the resistance of the LDR. Switch off the lamp, then back on and repeat the readings. Repeat once more. Take a mean average of the three readings.
5. Increase the distance from the lamp to the LDR by 5 cm and repeat step 3.
6. Repeat step 4 until the LDR is 40 cm from the lamp.

Safety

The bulb being used may get hot.
The bulb is made of glass which may break.