a) To bring across a message that ICT
enhanced learning not only complements textbook content but makes the task of learning
Physics an authentic real world
experience.
b) To
encourage more teachers to come on board in using ICT, like using of Tracker,
in teaching and learning of Physics.
c) To encourage
more teacher to collaborate and co-create resource for teaching and learning of
real world Physics.
See you at Science Centre on 12th and 13th Nov 2015. Session information: 12 Nov 2015, Sesssion 1.2
Comparison of Velocity-time graph for Model A & B:
Acceleration-time
graph - Model B compared to Model A
Model B has a deceleration of 17g, while Model A’s deceleration is 3.1g.
I think it is a bad idea to open the parachute
immediate while the parachutist is falling at 40 m/s. In real life, according
to a Discovery Education Channel video (https://www.youtube.com/watch?v=ur40O6nQHsw),
the parachute takes about 2-3 seconds to open fully.
Ideas for teaching and demonstration:
Adjust the
parameters and compare the velocity-time graph and acceleration-time graph.
Singapore GCE
O Level Physics /5058 2010 Paper 1 Q 3.
Question: At which point in Fig.1 A, B, C or D
is the parachute fully open?
From the
moment that the skydiver steps out from the plane, as his weight is the only
downward force acting on him, his start to accelerate. As his speed increases,
the air resistance increases. The air resistance or drag is proportional to v2
and the perpendicular area of a moving object.
D α v2.A,
where area, A, is constant because he does not use any parachute.
This
results in a decreasing downward resultant force. Hence, by Newton’s Second
Law, the acceleration is also decreasing as his speed increase. This continues
until air resistance reaches the same value of his weight.
At this
point the forces are balanced, hence he continues to fall at a constant speed,
it reaches terminal velocity (A') in Fig. 2.
From A’ to
B, he continues to fall at terminal velocity.
A Point B
At point B,
he pulls his parachute.
The air
resistance or drag is proportional to v2 and the perpendicular area
of a moving object.
D α v2.A
At B, the
gradient of the speed-time graph is negative and constant from the points of
speeds of 40 m/s to 25 m/s.
This
suggests that the deceleration at point B is constant. Hence, there must be a
constant upward resultant force present according to Newton’s 2nd
Law of motion, F=ma.
Immediately
after point B, when the parachutist continues to decent, its speed continues to
decreases.
According to the formula for D α v2.A, air resistance will
decrease when speed decreases. To maintain a constant air
resistance, area, A, must increase to compensate the decrease of air resistance due to
decrease in speed.
The above
means that the area of the parachute is not constant, but increases. This
suggests the parachute is in the process of opening from point B. Hence, at
point B, the parachute cannot be fully opened.
Point C
At point C,
supposed that the parachute is opened fully, the area, A is constant in the
drag force equation D α v2.A.
The air
resistance will decrease as the speed continues to decrease, since area, A, is
constant. From point C, the upward air resistance is still greater than the
weight of the parachutist. As the air
resistance decreases, the upward resultant force decreases. Hence the
deceleration of the parachutist is decreasing, which is evident from the
gradient of the speed-time graph from point C, this happens until it reaches
another terminal velocity (C’), where the air resistance equals to the weight
of the parachutist.
The above suggests that at point C in Fig. 1, the pareachute is fully open, not point B as the answer provided by Cambridge Marker's Report for the paper.
He continues to fall at the terminal velocity
until he reaches the ground.
For a better visualisation, please watch the video below
Great news! Journal paper published at IOPScience website.
This paper reports the use of Tracker as a computer-based learning tool to support effective learning and teaching of 'toss up' and free fall motion for beginning secondary three students.
I was amazed by the "turning heart" when I first saw a video of it. My quest to better understand how it works has ended up me making this video explaining the Physics behind it. The 'turning heart' in this video was a result of many ours of physical manipulation of a copper wire, a "AA' dry cell and a few very strong magnets which my Primary 5 boy Daniel bought for me at his School Science Fair. The "turning heart" is one of the many father and son science explorations!
Being inquisitive is Daniel! I hope this quality in him will carry him far in his pursuit of knowledge and discoveries in future. Hope to share more with you next time.
Tracker Software playlist on Youtube contains Tracker tutorials and tracker demonstrations videos, Useful to Physics teachers and students who use Tracker.
This video shows a paper model that teaches how to read a large value of negative zero error. Since it is hard to find a real micrometer with large negative zero error, hence this paper model is used as an ilustration for learning. Enjoy!
BECOMING SCIENTISTS THROUGH VIDEO ANALYSIS Workshop at eduLab@AST will be conducted on 4 Feb 2015 at Academy of Singapore Teachers.
We have about 18 21 participants in the workshop. What I hope to see at the end of this workshop is the Physics teachers from different schools are passionate in learning to harness the power of using video analysis tool to understand the real world phenomena, analyse, demonstrate and enthuse their students in doing so as well.
If you miss this workshop and want to participate in future workshops or interested in collaborate with us, drop me a note. I will be most willing to take it up with you from here.
The flow of the workshop:
1.(Tze Kwang, Ning, Kim Kia - 20 Minutes) Presenters will introduce the 8 Practices of Science Education adapted from the Science Framework for K-12 Science Education
2.(Lawrence - 10 Mins) as the design principles behind this ICT-enabled practice.
3.Break and Networking 20 mins
4.(Tze Kwang, Ning, Kim Kia - 60 Mins) Presenters will also demonstrate the effective use of Tracker, a video analysis tool, for analysis and interpretation of phenomena and
5.(Tat Leong and Tze Kwang - 30 Mins) in-depth model building. Participants will be oriented to the Tracker Shared Library where available models for physics concepts such as push and deceleration model.
6.Reflect and Feedback 10 mins
Objective:
·By the end of the session, participants should be able to:
·- Describe in detail at least one of the 8 practices of K12 science education framework
·- Download, install and use tracker basic analysis
·- Create at least one model in tracker for Practice 5 (mathematical and computational thinking)
Follow Wee Loo Kang's blog post images of the workshop and outcome of the participants' feedback.
