Q&A - P3 Science

[Tang]

[quote]May I just check, question 20,why is the answer not (1),I cant seem to demostrate the 360 rotation movement to my girl...thanks. [/quote]

tianzhu:

Shoulders and hips have ball and socket joints. They allow movement in all directions.
How to demonstrate? I wouldn’t suggest any unless you have the flexibility of a gymnast. As for me, my old rusty bones will crack if I attempt to do it.

For shoulder, you can demonstrate by swinging the arm round the shoulder in a circle.

Instead of demonstrating with hips, may be you can show her by rotating your neck SLOWLY in clockwise or anticlockwise direction.

[Lynn2]

Hi Tang


Thanks for the pointers.

Do you mind link up how this :melting point (deg cel) Boiling point(deg cel)
p 0 85
q -30 110
r -40 15
s 80 200

I am not able to explain to my girl based on the info you gave...maybe you can tell me how?thanks

Tang:

Lynn2:

Hi Tianzhu
Can someone explain to me on the co relation between the three states in relation to room temperature as illustrated in the questions.

Solid state - Temperature below Melting point

Liquid state - Temperature between Melting point and Boiling point

Gaseous state - Temperature above Boiling point.

Room temperature is below 30 degree C (about 28 degree C)

Based on above, P, Q, R and S are Liquid, Liquid, Gas and Solid respectively at room temperature. Hence answer is (1).

[Lynn2]

sorri, the number all go jumping


substance melting point Boiling point
p 0 85
q -30 110
r -40 15
s 80 200

[tianzhu]

Hi


At melting point, a substance changes from a solid to a liquid.
At boiling point, a substance changes from liquid to a gas.

Try to understand the concept using water before attempting to answer Q11.
Water melts at 0 degrees C and boils at 100 degrees C. At melting point, it changes from ice(solid) to water (liquid), at boiling point , it changes into from water(liquid) to steam(gas)

Now try Q11, it’s alright to assume room temperature as any figures from 25 degrees C to 28 degrees C.
Play around and you should get
P ----- liquid
Q ----- liquid
R ----- gas
S ------solid

The answer is option(1)

[Dharma]

tianzhu:

[quote]May I just check, question 20,why is the answer not (1),I cant seem to demostrate the 360 rotation movement to my girl...thanks.

Shoulders and hips have ball and socket joints. They allow movement in all directions.
How to demonstrate? I wouldn’t suggest any unless you have the flexibility of a gymnast. As for me, my old rusty bones will crack if I attempt to do it.[/quote]Good Morning Tianzhu,

I was just wondering if X (wrist joint) should have been one of the options in the answer. When we play badminton/hockey we always use the rotation of our wrist to hit the shuttlecock/dribble with the ball.

Pls advise. Thanks.

[tianzhu]

Hi Dharma


The skeletal system is covered very briefly in P3.I can’t find any information about wrist joints in my boy’s textbook. However in the PSLE guidebook from MPH, pg 59, only hips and shoulders are listed as having ball and socket joints.

I found this link during Google search.

http://www.eorthopod.com/public/patient_education/10069/what_type_of_joint_is_the_wrist.html

Best Wishes

[Dharma]

tianzhu:

Hi Dharma


The skeletal system is covered very briefly in P3.I can’t find any information about wrist joints in my boy’s textbook. However in the PSLE guidebook from MPH, pg 59, only hips and shoulders are listed as having ball and socket joints.

I found this link during Google search.

http://www.eorthopod.com/public/patient_education/10069/what_type_of_joint_is_the_wrist.html

Best Wishes

Thanks bro

[Lynn2]

Hi Tianzhu


Yes, managed to play around the figures with room temp, bingo and I
got it..thank you very much...

cheers

tianzhu:

Hi

At melting point, a substance changes from a solid to a liquid.
At boiling point, a substance changes from liquid to a gas.

Try to understand the concept using water before attempting to answer Q11.
Water melts at 0 degrees C and boils at 100 degrees C. At melting point, it changes from ice(solid) to water (liquid), at boiling point , it changes into from water(liquid) to steam(gas)

Now try Q11, it’s alright to assume room temperature as any figures from 25 degrees C to 28 degrees C.
Play around and you should get
P ----- liquid
Q ----- liquid
R ----- gas
S ------solid

The answer is option(1)

[Lynn2]

Hi ,


I found another question but dont have a scanner , so will type this out.

A Candle is lighted and its length is measured at different intervals of the time.How long has the candle been burning at c?

Begining A Whole candle is approximately 5 units
21 MINS later, candle B is approximately 3 units
? Mins,candle is approximately 2 units
42 mins later,its approximately 1 units.

The reason why I write approximately cos there is no more scale on the final part of the candle…

Option given is 28 or31 or 35 or 40

The teacher gives a calculation of 31.5 and assume the answer is 31.Just wonder, can this be done?thanks


rgds

[tianzhu]

Hi


Well, for experiments, we have to accept the fact that there would be experimental errors. We have to make allowances for differences in readings, something like parallax error in reading of measurements, or reaction to stopping of stop watches. This will lead to discrepancies in readings.

In this particular case, marginal differences in timings will not significantly affect the outcome. Yes, the teacher is right to take the average reading. And 31 is close enough to 31.5, don’t you think so?