The large and small of it

Measuring instruments:

• Vernier Calipers
• Micrometer Screw Gauge
• Metre Rule
• Ruler

Reading the Vernier Calipers:

1. Using the moveable scale (Vernier scale), find the length of the object down to 1mm.
2. Next, follow along the Vernier scale until you find a line that coincides with another on the main scale. Then, you can find the length of the object down to 0.1mm.

Here is an example:

1. I place a rivet in the Vernier Calipers and move the Vernier scale to measure the length of the rivet down to 1mm.
2. Next, I follow the markings along the Vernier scale to find the coinciding marking, thus finding my length down to 0.1mm.

Reading the Micrometer Screw Gauge:

1. Choose the correct micrometer for your application, and set the screw on the object you are measuring. Make sure it is snug but not overtightened.

2. Remove the micrometer and read the linear gauge. This gauge will most likely be abbreviated so that “24” equals “0.24 inches” or something similar, depending on the micrometer you are using.

3. Using the horizontal line on the linear scale as a pointer, read the scale on the barrel. The number of increments on the barrel will depend on the size of the step between increments on the linear scale. For example, if the linear gauge is divided into quarter steps, the barrel will have 25 increments.

4. Combine the readings. In this picture, the linear gauge reads 5.5 mm. Note that this particular gauge is not abbreviated. The linear gauge is divided into half steps, so the barrel gauge has 50 increments. This gauge reads “28,” which is an abbreviation for “0.28 mm.” The combined reading, then, is “5.78 mm.”

 

Zero Error:

When damaged, a Vernier Caliper may produce a zero error. This is when the markings of the Vernier scale does not line up with the markings on the main scale. To correct this, one must first determine if it is a Positive (+) Zero Error, or a Negative (-) one. Here are the steps of determining so:

1. Close the jaws fully
2. Should the markings on the Vernier scale fall on the right of the main scale, you have a Positive Zero Error. In this situation, find the extra amount (next step) and subtract it from you reading.
3. Look for the marking on the vernier scale that coincides with a marking on the main scale
4. See the marking that coincides with the vernier caliper

1. Close the jaws fully
2. Should the markings on the Vernier scale fall on the right of the main scale, you have a Negative Zero Error. In this situation, find the extra amount (next step) and add it from you reading.
3. Look for the marking on the vernier scale that coincides with a marking on the main scale
4. See the marking that coincides with the vernier scale.

How to barbeque

Hi all!

Here are the various types of flames:

Luminous flame

• Occurs when air holes are closed, and therefore the gas does not have enough oxygen to burn completely.
• Does not burn steadily.
• Orange/yellow in colour.

Non-luminous flame

• Occurs when air holes are open slightly
• Gas has enough oxygen to combust completely
• Blue in colour.
• Burn steadily.

Strikeback

• Occurs when there is too much oxygen, or when the air holes are suddenly opened, causing combustion to take place at the jet.
• In the case of a strikeback, turn off the gas immediately.
• VERY hot (up to 4000 degrees Centigrade).

Here is a cross-sectional diagram of the types of flames:

Oh and, by the way, here is how to heat a flammable liquid:

1. Place beaker on a tripod stand.
2. Put wire gauze in between the beaker and the stand.
3. Place the Bunsen Burner under the set-up and light.
4. Remove the Bunsen Burner when the water boils.
5. Place the liquid in the boiling water.

Lean Mean Burning Machine

Hi again!

This time, we have learnt the mechanics of a Bunsen Burner in preparation for our Practicals @ the Lab. Thus we were told of the instructions for lighting a Bunsen Burner:

1. Close the air holes.
2. Put lighter above the barrel.
3. Turn on the gas tap (don’t cross hands).
4. Strike the lighter to ignite the gas.
5. If unsuccessful, turn off the gas, wait for a while and retry.
6. If successful, open the air holes until a non-luminous flame (blue; more explained in the next post) is obtained.

We were also told of the structure of the Bunsen Burner:

Structure of the Lean Mean Burning Machine

Art Lesson?

Today we learnt the drawing of diagrams..

Every diagram you need to know.

In order of level from the top to the bottom:

1. Test Tube
2. Boiling Tube
3. Beaker
4. Conical Flask
5. Flat-bottomed Flask
6. Round-bottomed Flask
7. Measuring Cylinder
8. Burette
9. Pipette
10. Thistle Funnel
11. Filter Funnel
12. Displacement Can
13. Gas Jar
14. Bell Jar
15. Evaporating Dish
16. Crucible
17. Water Through
18. Tripod
19. Retort Stand
20. Distilling Flask
21. Liebig Condenser

That’s… a lot…

Attitudes of a Scientist

Today, we learnt that the attitudes of a scientist includes:

• Organised
• Observant
• Inquisitive
• Reference
• Having one’s own point of view
• Calm and composed
• Perseverance

We also learnt that Physics is…

• The study of matter and energy from the perspective of space and time. Models and theories are usually expressed using mathematical quations.

Whereas Chemistry is…

• The study of the properties of matter. Matter consists of atoms, or collections of atoms such as molecules, crystals or metals.

And finally, Biology is…

• The study of living organisms and the descriptions of the characteristics and behaviours of organisms, and the interaction they have with each other and their environment.

And we also learnt about the X-Y axis stuff on graphs.