In this post, we will be discussing the different types of energy and the reasons behind certain energy conversions with the aid of examination questions.
Conversion of Energy is a topic that is taught in Primary 6.
Students generally do not encounter any difficulty in stating the energy conversion that occurs in an object/person.
The challenge usually arises when the question requires the student to explain the reasons behind the energy conversions.
- The Escalator Energy Problem: Up or Down?
- Conversion of Energy Technique
- Mass & Energy: How These Two Concepts Work Together
- Heat Energy X Water Cycle: How Both Concepts Can Be Tested Together
As such, in today’s article, I’ll be sharing on the different types of energy and the reasons behind certain energy conversions, with reference to the following questions.
What Your Child Needs To Know About Energy
There are a total of eight forms of energy that primary school students are required to know:
- Gravitational potential energy (GPE)
- Chemical Potential energy (CPE)
- Elastic potential energy (EPE)
- Kinetic energy (KE)
- Light energy
- Sound energy
- Heat energy
- Electrical energy
Out of these eight forms of energy, our focus for today’s post will be on “Gravitational Potential Energy” (GPE) and “Kinetic Energy” (KE).
Gravitational potential energy (GPE) possessed in an object depends on:
#1 Height: The greater the height the object/person is from the ground, the greater amount of GPE possessed by the object/person.
#2 Mass: The greater the mass of the object/person, the greater amount of GPE possessed by the object/person.
Kinetic energy (KE) is also known as “moving energy”.
If the object/person is moving, the object/person possesses KE.
Besides knowing the different forms of energy, there is a rule of thumb on energy.
“Energy cannot be created or destroyed. It can only be converted from one form to another.”
With this in mind, let’s take a look at the above questions.
Here’s The Question
This question requires students to compare the GPE and KE at Point A and Point D.
Comparing the GPE between Point A and Point D:
Eunice is at a greater height at point A than at point D.
As such, the GPE possessed at point A is greater than the GPE possessed at point D.
Comparing the KE between Point A and Point D:
At Point D, most of the GPE of Eunice at Point A has been converted to KE at point D.
Therefore, the KE at Point D will be greater than the KE at Point A
As such, the answer for the above question would be Option 1.
Here’s The Question
Part (a): State the energy changes that take place in the car.
The petrol in the car possesses chemical potential energy, which is then converted to kinetic energy of the car when it moves.
Thus, the answer to this part is “Chemical Potential Energy -> Kinetic Energy”.
Note: Most students will find this part relatively easy! 🙂
Part (b)(i): What happens to the petrol consumption of the car when it’s travelling up the slope, as compared to it travelling on a straight level road?
As compared to travelling on a straight road, driving up the slope will cause the car to gain gravitational potential energy.
This would mean that more chemical potential energy is now needed to convert into more kinetic energy. This is because some of the kinetic energy is required to convert into gravitational potential energy.
Hence, the answer would be “The petrol consumption of the car increases”.
Part (b)(ii): Explain your answer in (b)(i).
When the car travels up a slope, more chemical potential energy from the petrol is required to be converted to more kinetic energy to travel the same distance.
This is because some of the kinetic energy of the car is converted to gravitational potential energy as the car moves up the slope, unlike travelling on a straight road.
Therefore, more petrol is needed to drive up a slope as compared to moving on a straight road.
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