1 cm = 0.01m
1 squared cm = 0.0001 squared m
1 cubic cm = 0.000001 cubic m
learn all these conversions by heart.
Saturday, March 20, 2010 10:06 PM
Corrections for Exercise 2 (Time, Rate & Speed)
♥Qn2
Average speed = 8.3m / 2.2hr
= 8.3 / 7920 m/s
= 0.001047... m/s
= 0.00105 m/s ( 3 sig. fig.)
credits to Joie Tan of 104 who highlighted the error :)
Thursday, March 18, 2010 11:39 PM
Time, Rate & Speed Notes
♥A. Time
1. Time is the duration of an event which is measured in seconds (s).
2. SI Unit: seconds (s).
3 Other measurements of time include days, hours, milliseconds, and minutes, etc.
4 Instruments commonly used to measure time include mechanical stop-watches, electronic stop-watches and hour-glass.
5 The most accurate method of time keeping is the usage of atomic clocks, where every second is equivalent to a fixed number of periods of radiation from the ground state of the Caesium 133 atom.
B. Rate
1. Rate is the expression of a specific ratio in which measurements of two physical quantities are related to each another.
2. The measurements of the two physical quantities may be of different units, e.g. m/s and m/min, OR km/min and m/min.
Conversation table
Example 1
240m/min = 4m/s
Example 2
12km/min = 12000m/min
= 200m/s
3. Conversation of rates allows us to make a fair comparison when we are using the same rates.
4. Other examples of rates would include cm/s, km/h, $/min, and kg/m2.
C. Speed
1. Speed is the measurement of Distance (m) over Time (s).
2. SI Unit: metre per second (m/s).
3. Other measurement units includes miles/h, yards/min.
4. Speed tells us how fast an object is moving, and it is a rate at which distance is covered over time.
5. As an object may not be of constant speed throughout its motion, there would be a need to calculate its average speed.
6. Average speed is the measurement of total distance travelled over total time taken.
11:32 PM
Time, Rate & Speed Exercise 2 Answer Schemes
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11:31 PM
Time, Rate & Speed Exercise 1 Answer Schemes
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Sunday, March 7, 2010 3:02 AM
GROUP 1 - LENGTH & MEASUREMENTS
♥ GROUP 1
Members.
♥Anthea Koh
♥MaryTreesa
♥Nicole Kessler
♥Sheerin
♥FooSuYi
We will be telling you more about Length & Measurments
The SI unit of length is metre
METRE RULE
The metre rule is commonly used in the classroom or laboratory
to measure the length of an object , place one end of the object against the zero mark and read off the mark on the rule at the other end of the object.
MEASURING TAPE
for lenghts greater then 1m in length , a measuring tape can be used .Measuring tapes come in different lengths - some can be as long as 60 m!
Measuring tapes used by tailors are usually soft and flexible while the measuring tape used for carpentry is stiff, curved metalic ribbion.
Vernier calipers
Vernier calipers are used to measure short lenghts and diameteres of objects of up to 10cm.
They provide a more accurate measurement then the metre rule.
How to use a vernier caliper:
1. Close the jaws of the vernier caliper and ensure that the zero
marking on the vernier caliper scale is in line with the zero marking
on the scale.
2. Place the object within the jaws of the vernier calipers and clamp
it firm in place. 3. Hold the vernier calipers perpendicular to your eyes and read the measurements.
Zero error
- A zero error is when the jaws of the vernier calipers are fully
closed and the zero marking on the vernier caliper scale does not
coincide with the zero marking on the scale.
There are two types of zero error:
- Positive zero error
It is when the jaws of the vernier calipers are closed and the zero
marking on the vernier scale falls on the right side of the zero
marking on the main scale.
-Negative zero error
It is when the jaws of the vernier calipers are closed and the zero
marking on the vernier scale falls on the left side of the zero
marking on the main scale.
Centimetre ruler:
Is almost similar to the metre ruler, except for the size.Used in geometry and simple measurements like the measurement of the thickness of a book.Its unit is in centimetres.
Monday, March 1, 2010 2:57 AM
♥mass. GROUP MEMEMBERS of GROUP 3::
CHARMAINE TER(5) - LEADER (:
INSYIRAH BANU(13) - DOER (:
CLAUDIA LEONG(21) - TIMEKEEPER (:
SAMANTHA RACHEL(29) - DOER (:
VANESSA TOH(37) - OBSERVER (:
The SI UNIT for Mass is Kilograms ( KG)
COMMONLY USED APPARATUS TO MEASURE WEIGHT:
Triple Beam Balance
A triple beam balance is an accurate and reliable method of measuring mass. Most triple beam balances can measure masses up to 0.61kg.
Four-beam Pan Balance
A four-beam pan balance can measure masses up to 0.311g.
Electronic Balance
An elctronic balance can obtain readings much faster than a beam balance.
Mass is not equivalant to weight.
The difference between mass and weight is apparent when, for example:
-objects are compared in different gravitational fields, such as away from the Earth's surface. For example, on the surface of the Moon, gravity is only about one-sixth as strong as on the surface of the Earth. A one-kilogram mass is still a one-kilogram mass (as mass is an intrinsic property of the object) but the downward force due to gravity is only one-sixth of what the object would experience on Earth.
-an object is immersed in a liquid or gas. For instance, a brick weighs less when suspended in water, even though its mass is unchanged, and a helium balloon in the atmosphere appears to have negative weight, even though its mass is positive.
Weight is a force that results from the action of gravity on matter. it measures how strongly gravity pulls on that matter. THINGS THAT MEASURE WEIGHT:
Weighing scale
Spring scale
FAQ:
What is mass?
Mass is the amount of material in an object. Mass stays the same no matter what force is acting on the object. This makes mass different from weight, which depends on both the amount of mass and the amount of gravity. This means that even though our elephant weighs less on the moon, his mass stays the same.
What is the SI unit for mass?
it is (kg).
What are some commonly used units in mass?
kilograms,grams,pounds,milligrams,etc.....
d)What is a triple beam balance and how is it used?
The triple-beam balance is the instrument most frequently used to
measure the mass of an object. There are 3 ways in which the triple-beam balance
may be used to measure mass,but only 2 is here.
1. Finding mass directly: The object is placed on the pan of the balance and the
riders are moved into position on the beams until the pointer is balanced at the zero
point. The mass is determined by the positions of the riders on the beams.
2. Finding mass by difference: This procedure is most frequently used to find the
mass of a liquid in a container. The mass of the empty container is subtracted from the
combined mass of the container and the liquid.
ei)What is a spring scale?
A spring scale is a device that uses the translation of a spring by force due to weight to discover the mass of an object.
eii)How to use it?
The spring scale uses a spring attached to a hook to work. The object to be weighed is hung from the hook, which compresses the spring. The amount that the spring is compressed is read on a scale.
CREDITS:
Samantha Rachel and Insyirah Banu for doing the blog.
Claudia Leong for taking pictures for the blog.
Charmaine Ter for doing the FAQ.
Vanessa Toh for giving advice and notes for the blog.
Thank you for looking at our project!
Sunday, February 28, 2010 12:58 AM
♥
Group 2 Celine , Hilya , Laura , Phoebe and Vanessa Tee
Volume
What is volume ?
Volume is a measure of the space occupied by a substance.
The S1 unit, common units used and conversion between various units of volume.
It is a glass or transparent plastic cylinder used for measuring liquid volumes, especially in chemical analysis.A measuring cylinder is also known as a graduated cylinder.
Beaker
It is a cup usually having a wide mouth a plastic beaker and a puring lip. The use of the beaker is to hold and pour liquids . They can also be used to heat liquids. It is really just a round glass container with a flat bottom. They come in many sizes, from tiny ones that only hold 10 mL to giant ones that hold many liters.
Pipette
The pipette is also called the pipet ,pipettor or chemical dropper.They are used in a laboratory to transport and/or measure a
specific volume of liquid.
Burette
Burettes measure from the top since they are used to measure liquids dispensed out the bottom. The difference between starting and final volume is the amount dispensed.
parallax error
is the error in measurement due to eye not positioned perpendicularly at the the mark on the scale.
READING THE MENISCUS is a curve in the surface of a molecular substance and is produced in response to the surface of the container or another object.
A:the bottom of a concave meniscus. B:the top of a convex meniscus.
Irregular Solids: use a displacement can or a measuring cylinder.
For example: I have a golf ball and i want to know whats the volume of it. i can use either a displacement can or a measuring cylinder.
Using a measuring cylinder: i put 20mL of water in it. i put the golf ball in the measuring cylinder. make sure no water splats out.Then read the reading,for example 100mL. Therefore the volume of the golf ball is 100mL-50mL=50mL
Friday, February 26, 2010 7:43 AM
Temperature
♥Group 4
-Dayana (Group Leader)
-Joey (Doer)
-Shabana (Doer)
-Yucen (Time Keeper)
-Si Hui (Observer)
Theme: Physical Quantities, SI Unit and Mearsurements
iv. Temperature
What is temperature?
Answer: Temperature is the measurement of how hot or cold something is.
Temperature is the amount of heat in a substance.
What is heat?
Answer: Heat is the energy in the substance. (Heat is an energy)
What is the SI Unit for temperature?
Answer: The International System of Units (SI) for temperature is kelvin (Symbol:K)
*0 K = −273.15 °C
However, temperature is most commonly measured in degree Celsius or Fahrenheit.
What is used to mearsure temperature?
Answer: A thermometer. There are many kinds of thermometer to measure things at different situations.
What is a thermometer?
Answer: Thermometer is a greek work. "Thermo" means warm. "Meter" means to mearsure. There are two types of thermometer(primary and secondary thermometer). For primary thermometers the measured property of matter is known so well that temperature can be calculated without any unknown quantities.
Secondary thermometers are most widely used because of their convenience.Secondary thermometers are usually more sensitive than primary ones.
Types of termometer:
*Alcohol thermometer
*Beckmann differential thermometer
*Bi-metal mechanical thermometer
*Coulomb blockade thermometer
*Galileo thermometer
*Infrared thermometer
*Liquid crystal thermometer
*Medical thermometer (e.g. oral thermometer, rectal thermometer, basal thermometer)
*Mercury-in-glass thermometer
*Pill thermometer
*Recording thermometer
*Resistance thermometer
*Reversing thermometer
*Silicon bandgap temperature sensor
*Six's thermometer- also known as a maximum minimum thermometer
*Thermistor
*Thermocouple
*Phosphor thermometry, phosphorescence can be used to detect the temperature of an object
eg a gas turbine component
Common thermometers:
*Liquid-in-glass thermomether. (mercury and alcohol) [Usually used in laboratory]
Why?
This thermometer relies on the expansion of liquids with respect to heat, to accurately measure temperature.
Mercury is commonly used in thermometer because it is sensitive to temperature change and expandsd also linarly with temperature. It means that for every unit temperature change, it expands by a constant and significant amount.Mercury has a low freezing point and it remains as at liquid form at room temperature. Mecury mearsures from -10 degrees celsius to 110 degree celsius.
Alcohol is usually used in thermometers when there is a need to mearsure very low temperatures as it has a lower freezing point then mercury. Alcohol mearsures from -117 degree celsius to 78 degree celsius.
*Clinical thermometer
The clinical termometer is used to mearsure body temperature within a range of 35 degree celsius to 45 degree celsius. The traditional thermometer has a constriction to prevent mercury from flowing bacl into the bulb when the thermometer is being removed from the body. The normal human body temperature is 36.9 degree Celsuis.
*Digital Thermometer
Now, the most commonly seen thermometer is the digital thermometer. It is so convenient to use it as it only requires a touch of a button. Some thermometers take temperature for the ear, while others take temperature orally.
The accuracy of the thermometer is very important. We can sence how hot or cold a substance is by touch it but it will not be accurate method of mearsuring temperature. For instance, one is unable to accuratrly tell if another is having a fever simply by putting a hand on the forehead.
~~~~~~~~~
How to use a laboratory thermometer (mercury)?
Safty comes first! Always remember to wear safty goggles before starting an experiment.
Apparatus you need:
First, fill the mearsuring cylinder will 100cm3.
Pour the water into the beaker.
Place the tripod stand above the bunsen burner. Light the bunsen burner. Place the wire-mesh on the tripod stand.
Ajust the thermometer properly to the retord stand.
Do make sure the the thermometer is not touching the beaker.
Never do this:
It is very dangerous.
The end, thankyou for reading out science project. God bless!
4:44 AM
group 7 - volume
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there will be more below!!!! enjoy !!!!! =D
4:41 AM
group 7 - volume
♥
there will be more below!!! enjoy !!! =D
4:30 AM
group 7 - volume
♥
there will be more below !!!!! enjoy!!! =D
12:09 AM
group 6
♥
This is a measuring tape.
This is how to use a measuring tape:
Hold the front of the tape at the point you wish to start the measurement from, and extend it to the point where you want to stop.
Read the first large number before your stop point - this will tell you the number of inches. Read the smaller lines of various sizes. Remember what the various sizes will make up until your stop point.
This will tell you your fraction of an inch.
Then there will be your measurment of the object!
Thursday, February 25, 2010 10:59 PM
Measurement of Length and Area, group 6 (;
♥Length and Area! (;
hello you there! we are the group six people. We have our group leader Elizebeth, and the other four members Jiaxin, Valerie, Rachel and Cherinalek! and.. we are going to bring you to a journey ofLENGTH AND AREA. We are going to do 5 things on length and one thing on area. The 5 things are the vernier calipers, internal calipers, external calipers, measuring tape and ruler and the one thing on area is the square grid. We are excited, are you? (; alright, then let's go!
and now.. welcoming the.. inside measuringtape. joking, its the INTERNAL CALIPERS. hahaha.
okay.. INTERNAL CALIPERS.
The internal caliper works like the external caliper.The internal caliper is the reverse of the external caliper meaning the contact measuring points are turned out instead of in. So, the internal calipers has a totally different jaw as the external calipers.We use the internal calipers for meausing the places that a metre rule isn't able to measure. For instance, we want to find out the circumference of the beaker, so we place the internal calipers at slightly the tip of the beaker and extend the jaws of the internal calipers then use a metre rule to measure how wide the jaws are and there, you got an answer! (; EXTERNAL CALIPERS.
How to use a external caliper? The external caliper is designed specially for taking external dimensions.The instrument must be closed on the part throughly, but not forced.In general, the part should be stationary. Once the sliding jaw and fixed jaw contact the part, tighten the screw on the top of the fine adjustment. Only when you begin to move the sliding jaw toward the part with the fine adjustment screw while simultaneously making sure to align the instrument so that the flat of the jaws is completely contacting the part squarely. Once the jaw will no longer move forward with modest pressure from the adjusting screw,p and take the reading.
THE RULER How to use a ruler?? Rulers are thin slats marked out in English or Metric units of measure. In the US they are one foot foot in length. Ruler comes in wide variety of lengths.It is used to make measurements like length, width and height. a measuring stick or a king.
VERINER CALIPERS
They are digital caliper, micrometer caliper and the divider caliper. These are the different types of venier caliper. We normally use it to measure things that are unabled to be measured by the normal ruler, Here are the steps on how to use a venier caliper. First, put your workpiece inbetween the jaws of the vernier calipers then close the jaws and make sure the 0 of the main scale is in the same line as the 0 in the vernier scale avoding zero error to occur. Then, look at the measurement of the vernier scale and the main scale and then add them together to find your answer of the measurement of the workpiece!
Area. We are now proceeding to Area now. we are doing on the SQUARE GRID for area.
SQUARE GRID. What is a square grid?
Square grid is used to measure irregular figures. For example a leaf. We can't measure a leaf with a ruler but we can use a square grid. How the square grid works: First, draw the shape of the object on the square grid. Make sure the object u drew follows the same measurments of the original object. Then, tick the boxes with has more than half a sqaure shaded. Next, calculate one of the boxes area. For example, the length of the square is 1cm. so the area of one box is 1cm x 1cm equals 1cm. After that, take the number of ticks and times(x) the area of one sqaure box and taaaaadaa, you got your answer. (;
MISSION ACCOMPLISHED! okay, we have another 30 slides of measurements for you on mirscosoft! joking.. hahaha. anyway, we hope you got a rough idea of length and area. alright, BYE! God bless (;
pictures were taken from goooooogle.
