The last topic listed the ten parts of a report. This topic shows those parts being used together in three real examples, so you can see exactly what a finished report looks like. As you read each one, keep asking yourself which of the ten parts you are looking at, and notice that a short report does not always use all ten.
1Observation of the Volume of Air
- Objective
- To test whether air has a fixed volume.
- Materials
- An empty mineral water bottle.
Procedure: The bottle cap was closed tightly so no air could get in or out. The bottle was squeezed smaller from the bottom. Once it could not be squeezed any further, the cap was opened.
Observation: Air rushed out with force when the cap was opened after squeezing. Result: A large amount of air was pushed into a much smaller space.
Conclusion: Air does not have a fixed volume. It can be squeezed into a smaller space.
Why does that work? Air is a gas, and the tiny particles in a gas sit very far apart from one another with a lot of empty space between them. Squeezing the bottle simply pushes those particles closer together, and the same amount of air now fits into less space. Try the same thing with a bottle full of water and you will find it barely moves at all, because in a liquid the particles are already packed close together with almost no room left to squeeze out.
2Property of Air: Oxygen
- Objective
- To prove that air contains oxygen.
- Materials
- Matches or a lighter, a candle, a glass, a container of water.
Procedure: A candle standing in water was lit. The burning candle was then covered with a glass.
Observation: The candle went out after a short while inside the covered glass. Result: The oxygen trapped inside the glass helped the candle burn. Once that oxygen ran out, the flame died. The rise in the water level inside the glass showed that some of the air had been used up.
Conclusion: Air contains oxygen mixed within it.
The important idea here is that the flame did not stop because it ran out of candle. There was plenty of candle left. It stopped because the one thing it needed from the air, oxygen, had been used up inside that sealed glass. Notice also how careful the wording of the conclusion is. It does not claim that air is oxygen, only that air contains oxygen mixed within it, because the flame burned for a while before going out rather than not burning at all.
3Distillation
- Objective
- To separate salt and water from salt water.
- Materials
- Round bottom flask, cork, conical flask, tripod stand, burner, condenser, wire gauze.
Procedure: A round bottom flask was filled halfway with salt water and placed on a tripod stand. A condenser was connected to the neck of the flask, with cold water flowing around it. An empty conical flask was placed to catch whatever came out of the condenser. The salt water was then heated with a burner.
Observation: After heating for about 10 to 15 minutes, the water began to boil and turned into vapour. The vapour cooled inside the condenser and turned back into water, which dripped into the conical flask. Only salt was left behind in the original flask. Result: Salt and water were separated from the salt water.
Conclusion: Distillation can separate a dissolved solid and a liquid from a solution.
Distillation works because of one simple difference between the two things being separated. Water turns into vapour when it is heated, but salt does not. So when the mixture boils, only the water leaves the flask, travelling away as vapour and abandoning the salt behind. The condenser then does the opposite job: cold water flowing around it cools the vapour back into liquid water, which drips out clean and free of salt. Two changes of state, evaporation and then condensation, are all that this whole apparatus is arranging.
Reading a report with a critical eye
Now look back at all three reports together and count the parts. Each one has an objective, materials, a procedure, an observation, a result, and a conclusion. That is six of the ten. Each also has a title and a figure, so eight. But none of the three includes an analysis, and none includes a precaution.
This is not a mistake in the textbook. Short sample reports are often trimmed to the parts that matter most for the point being made. But it is worth noticing, because it is exactly the kind of thing you should be able to spot now. The candle report in particular could use a precaution, since it involves a lit flame, and the paragraph above about oxygen being used up while candle wax remained is really an analysis that the sample report never wrote down. Being able to see what a report leaves out is a genuine skill, and it is the difference between reading a report and simply believing it.
TODO: Add YouTube video ID for Sample Practical Reports
The Holes in a Lantern
Here is how one student reasoned it out, and then wrote the answer up in report form. Notice that the reasoning came first and the writing came second, which is the correct order.
★Why a Lantern Has Holes
- Objective
- To explain why a lantern is built with small holes at the top and bottom of its glass.
What I already knew: From the candle experiment, a flame goes out once the oxygen around it is used up. The candle under the glass had plenty of wax left, so it was not the fuel that ran out. It was the oxygen.
My reasoning: A lantern flame is also surrounded by glass, so it should have exactly the same problem as the covered candle. It should use up the oxygen inside and go out within a minute or two. But lanterns clearly do not do that, because people burn them all evening. So something must be letting fresh air keep reaching the flame, and the only openings in the glass are those small holes.
Explanation: The holes at the bottom let cool, fresh air carrying oxygen flow in to the flame from below. The hot waste gases produced by burning rise upwards and escape through the holes at the top. This sets up a steady one-way flow of air, in at the bottom and out at the top, so the flame never runs out of oxygen the way the covered candle did.
Conclusion: The holes are there to keep air moving past the flame. Without them the lantern would behave like the candle under the glass and go out within a short time.
What I liked about this question is that I did not have to do a new experiment to answer it. I already had the evidence, from the candle in the glass, and all I had to do was carry that same idea across to a different object. Our teacher called this transferring a result, and she said it is one of the most useful things science lets you do. My friend Prakash pointed out something I had missed, though. He said the top holes are not only for waste gas, they also stop the hot glass from cracking, because the heat has somewhere to go. So one design can have more than one reason behind it, and my explanation was right but not complete.
| Report | Parts present | Parts missing |
|---|---|---|
| 1. Volume of Air | - | - |
| 2. Oxygen in Air | - | - |
| 3. Distillation | - | - |
A sample report shows the ten parts of a report actually being used together.
Squeezing an empty bottle shows that air does not have a fixed volume.
Air can be squeezed because the particles in a gas sit far apart, with empty space between them.
Covering a burning candle with a glass shows that air contains oxygen.
A flame goes out once the oxygen trapped with it is used up, not because the wax runs out.
Distillation separates a dissolved solid from a liquid in a solution.
Distillation works because water turns into vapour when heated but salt does not.
A condenser is the part that cools the vapour back into liquid.
Short sample reports often leave out some of the ten parts, such as analysis and precaution.
Being able to see what a report leaves out is as useful as being able to read what it says.
The video for this topic is being prepared. Check back soon!
Sample Practical Reports
Science & Technology · Grade 7
Report 1: The Volume of Air
- Objective: does air have a fixed volume?
- The sealed bottle was squeezed as small as it would go
- Opening the cap released air with real force
- Conclusion: air has no fixed volume
Report 2: Oxygen in Air
- A lit candle standing in water was covered with a glass
- After a short while the flame went out
- Plenty of wax was still left, so fuel was not the problem
- The water level inside the glass rose
Puzzle: The Holes in a Lantern
- A lantern flame is also closed inside glass
- So why does it not go out like the covered candle?
- Look closely: small holes at the top and the bottom
