(Primary Science) Be precise and accurate!

Although primary science is science at elementary level, the phrasing of answers has to be precise and accurate to minimize misconceptions / misunderstandings so as to ensure a firm foundation before going to the secondary level. It's impossible to list all examples of imprecise phrasings in students' answers that cost them marks. Here are a few examples to give you an idea.

1. State one disadvantage of deforestation.
Student's answer: It leads to global warming.
Comment: One correct answer is that deforestation causes soil erosion. If you quote global warming which is not wrong, you need to explain how by saying that deforestation decreases the number of plants to take in carbon dioxide in the air.

2. Name the cell that transports oxygen from the lungs to all parts of the body.
Student's answer: Blood
Comment: Blood is a tissue, not a cell. The correct answer is "red blood cell". If you write "blood cell", you won't get a mark too. Don't forget that there are also white blood cells that do not transport oxygen.

3. Cutting a part of the small intestine may help to solve the problem of obesity of a patient. How?
Student's answer: The patient will not be able to take in food.
Comment: This answer is both vague and negative. You need to mention about "food absorption" as this is the function of the small intestine. You can't say that there is no food absorption because only a part, not the whole, of the intestine is removed. So, the correct answer is to explain that smaller area of absorption may lead to decreasing rate of food absorption.

4. How does reforestation help to reduce the problem of global warming?
Student's answer: More plants take in carbon dioxide.
Comment: This is a 2-mark question. The student's answer is true but inadequate and so may score only 1/2 a mark. Give the name of the process "photosynthesis" in which plants take in carbon dioxide. And there is a need to mention that there will be less greenhouse gas in the air to trap heat from the Sun.

5. A ball rolls down a ramp and travels a distance on the floor before it stops. Why does the ball stop?
Student's answer: Due to friction
Comment: This is correct. However, if it is subject to a marking scheme that is more demanding, the student would not get the full mark. It is safer to elaborate that the kinetic energy of the ball is converted to heat due to friction.