USE SCIENTIFIC UNDERSTANDING TO EXPLAIN YOUR PREDICTION.
Explain your prediction based on what you have learnt. You may refer to preliminary work you have carried out. You may also include other evidence of research, including secondary sources (although you must indicate this). Comment on possible controls and factors, which may prevent you controlling some variables effectively.
In the all or nothing experiment this proves that the feathers causes less heat to escape the test tube. When the plastic bag has feathers in or no feathers the heat will still escape the test tube and these are the 3 main ways heat will be lost from the tube.
Conduction – this is the main way of heat transfer through the test tube. This is the definition of conduction – The only way of heat loss through opaque solids is by conduction. If something is heated at one end it will spread through the solid by conduction. What happen in conduction in the heated side of the solid the particles starts to vibrate eventually the whole of the solid will vibrate. When the particles of the solid vibrates the temperature of the solid will be the same throughout.
The way conduction effects this experiment is like this. Once the heat has got to the tube by convection the heat will travel through it by conduction then it will travel through the bag and feathers by conduction is well. This is the way most of the heat will transfer in the experiment.
Convection – here is the definition of convection. This is the motion of heat through fluids and gases. The heat travels from one part of the fluid or gas to another. If a liquid or gas is heated, its density or mass per unit decreases. The hotter the liquid makes it less dense so it will rise to the top then the colder or denser fluids will sink this is called a convection current.
The way convection effects this experiment is like this the heat will be moved to the glass by convection then the heat will be moved from here by conduction. Then from the feathers it leaves by convection. This does not play a big part as conduction.
Radiation – here is the definition of radiation. In radiation heat travels through no substance. Radiation is able to travel through a vacuum. Dull substances are able to absorb heat by radiation especially dull and rough surfaces. So in this experiment radiation will affect it like this the heat will be transmitted by radiation from the fluid then some of it will be absorbed. Then it will leave the feathers some of the heat by radiation. (The above definitions were helped from research from Encarta)
From more research I have found out that penguins have an oil gland on
their backs. This oil gland secretes over their feathers so when they get wet the water will just run off their feathers making them function normally.
When the feathers have been transmitted the heat by conduction, convection and radiation I have found out that they are good at keeping this heat. What makes them good at keeping the heat is because between the strands of feathers is trapped air and air is a very good insulator this is how they work.
An example of something else that works in the same way is human skin that has hairs on it.
WHAT MEASUREMENTS DO YOU INTEND TO TAKE?
List the range and number of measurements you intend to take. State whether you will each measurement and how many times.
During this experiment I will have to take a lot of measurements here they are –
- The heat of the water will have to be 55 C – 60 C I will use a thermometer to measure this.
- The different amounts of feathers I intend to take will be 2g, 4g, 6g and 8g I will get these measurements by using electronic scales.
- The amount of water will be 4omls so a measuring cylinder will measure this.
- After I have done each experiment with all of the different weights I will have to repeat it to make it more accurate.
DESCRIBE YOUR PROCEDURE.
State your method clearly and concisely in a point form. Make it accurate by including all details, volumes and amounts. Include an apparatus list and, if necessary a clearly labelled diagram. Remember a fair test.
APPARATUS LIST
SCALES STOP WATCH
FEATHERS ELASTIC BANDS
WATER BATH TONGS
CLAMP STAND
TEST TUBE
MEASURING CYLINDER
PLASTIC BAG
THERMOMETER
SET UP OF EXPERIMENT
METHOD
(With no feathers)
- Collect all of the apparatus and find a clear bench to work on.
- Get a plastic bag and wrap it around the test tube. Put an elastic band around it to stop it from falling off.
- Clamp the tube to the clamp stand.
- Now collect 40ml with a measuring cylinder from the water bath and pour it carefully into the test tube.
- Now put the thermometer into the test tube and read the temperature when the temperature reaches 55 C – 60 C you can start the stopwatch.
- Using the stopwatch take the temperature every 1 minute for 10 minutes.
- Now repeat this experiment to get an average.
(With feathers)
- Now you need to start to add feathers into the plastic bag.
- Measure 2g on the electronic scales and put them into the plastic bag and spread them evenly through the bag.
- Now wrap the plastic bag around the test tube and use an elastic band to hold the bag to the test tube.
- Clamp the test tube to the clamp stand.
- Measure 40ml in a measuring cylinder from the water bath pour it carefully into the test tube with feathers around it.
- Now put the thermometer into the test tube and when it reaches 55 C – 60 C you can start the test tube.
- Now take the temperature every minute for 10 minutes then repeat the experiment.
- You will have to do the same for 4g, 6g and 8g.
HOW HAVE YOU MADE THE EXPERIMENT MORE ACCURATE?
State how your experiment helps you to gain results. Include controls and secondary experiments.
The ways I made the experiment more accurate is like this –
- For all of the different measurements of feathers I took the temperature in the same place this is because of convection currents.
- I tried to keep the experiment in the same environment to do this I done all of the experiments in the same place of the classroom. This is to try and keep the same room temperature.
- I used the same equipment for all the experiments to try and keep it equal throughout.
- I used a measuring cylinder to get the exact amount of water.
- I used a thermometer to get the right starting temperature and to measure the temperature when I need to.
PRESENT YOUR RESULTS IN A SUTIBLE METHOD.
Og of feathers Rate of heat loss = 1.4 C per minute
2g of feathers Rate of heat loss = 1 C per minute
4g of feathers Rate of heat loss =1.2 C per minute
6g of feathers Rate of heat loss = 0.85 C per minute
8g of feathers Rate of heat loss = 0.5 C per minute
EXPLAIN SIMPLY WHAT YOUR RESULTS SHOW.
From my experiment, roughly I can see that the rate of heat loss decreases as the amount of feathers increase this is what happened –
- 2g of feathers = 1 C per minute
- 4g of feathers = 1.2 C per minute
- 6g of feathers = 0.85 C per minute
- 8g of feathers = 0.5 C per minute
From looking at the all or nothing experiment I can see that the feathers are causing the heat loss to decrease because the one with no feathers had the heat loss of 1.4 C per minute and the one with feathers had the heat loss of 0.5 C per minute.
WHAT TRENDS, PATTERNS OR RELATIONSHIPS CAN YOU SEE IN YOUR RESULTS?
Describe the overall pattern of your results. Identify any anomalies in your results.
When I am looking at the rate of heat loss for the experiments I have noticed that when we look from 2g to 4g the rate of heat loss goes up. At 2g the rate of heat loss is 1 C per minute while when at 4g the rate of heat loss is 1.2 C per minute.
After this the rate of heat loss in 6g is less than the rate of heat loss in 8g this reflects my prediction.
In the all or nothing experiment I can see that the experiment with no feathers the rate of heat loss is far greater than the bag with feathers in it.
Another pattern that sometimes is reflected in my results is that as I double the amount of feathers it will halve the amount of heat loss.
EXPLAIN YOUR RESULTS SCIENTIFICALLY AND RELATE TO YOUR PREDICTION.
Make a conclusion on the evidence you observed and collected. Do your results support your conclusion? Explain your results in terms of science you have learnt, and comment on possible reasons behind irregular results.
From looking what is written in my prediction I would say that my results roughly reflect that my prediction was right.
The reasons for why as I increase the feathers the rate of heat loss decreases is that as you increase the feathers you are increasing the amount of trapped air between the feather strands and air is a very good insulator so the heat will be insulated within the feathers.
The irregular results was in the 4g of feathers this is because it has a greater heat loss than 2g I would say the reasons for this could be a change in the environment this could make the temperature of the test tube go up or down or it could be due to the different types of feathers.
In my prediction I said that if I double the amount of feathers the rate of heat loss is halved. I can prove this is right when I look at my results this is what I discovered at 2g of feathers for the first minute the heat loss was 3.5C
and when looking at 4g of feathers the heat loss after 1 minute is 1.5 C this basically proves this part of the prediction to be right.
When looking at the all or nothing experiment I predicted that the bag with no feathers would have a greater rate of heat loss and I was proven right by the results. This is because the bag with feathers will have more trapped air within it because of the way feathers trap air and feathers and air is a very good insulator.
COMMENT ON THE SAFETY OF THE PROCEDURE AND WHETHER IT WAS A FAIR TEST.
State whether the procedure was fair in all aspects or were some variables difficult to
This experiment cannot be a fully fair test due to aspects that are uncontrollable what I am talking about is the environment you cannot control the environment temperatures, if it goes up or down it can make the temperature of the test tube go up or down.
The plastic bag around the test tube will provide a source of insulation because it is able to trap air. Also the top and the bottom of the tube are not covered so heat may be lost in these places.
The way of keeping this experiment safe is by using tongs to handle the hot test tubes and clamp the test tube firmly to the clamp stand to stop it from falling and braking.
HOW ACCURATE ARE YOUR RESULTS AND DID YOU GET ANOMALOUS RESULTS.
State any limitations or problems with the experimental procedure. State whether you got any anomalous results and why you think you got them. Can we still accept the evidence? Is the evidence sufficient to support a firm conclusion?
The irregular results are at the 4g readings. The rate of heat loss for 4g is greater than the rate of heat loss in 2g.This could be due to a change in the environment or because of different types of feathers. Some feathers may be able to trap more air than other; this may explain why the rate of heat loss is greater in 2g than 4g of feathers.
The thermometer may have been moved into a different part of the test tube when reading the temperature causing the temperature to go up.
We can still accept this evidence because they all follow the same basic pattern.
HOW COULD THE EXPERIMENT BE MADE MORE ACCURATE?
Give full details of changes you could make to the method to make it more accurate. State any further work that could be carried out to investigate the problem further.
To make it more accurate you would have to take the temperature in the same place in the test tube. The way to do this is to have an extra clamp to hold the thermometer in the same place so it does not touch the glass because this can affect the temperature.
There is heat loss in the top and bottom of the test tube, a way you can stop this by if you put the test tube in a pouch to cover the bottom. A rubber bung can stop the heat loss in the top with a hole in to put the thermometer in.
Another way to get the readings more accurate is to repeat the experiment again this enables you to get a more accurate average.