PIMSO 2023 - Science - Primary 4 - National Round

Question 1

Spherical nodules can be found in the roots of leguminous plants which contain bacteria that fix which particular element?

Image source: https://commons.wikimedia.org/

1. Carbon
2. Nitrogen
3. Phosphorus
4. Potassium
5. Magnesium

Question 2

The following coloration is exhibiting which type of animal adaptation?

Image source: https://commons.wikimedia.org/

1. Batesian mimicry
2. Müllerian mimicry
3. Camouflage
4. Aposematism
5. Mate selection

Question 3

Which of the following trophic models demonstrates omnivory in an ecological community?
Reference: Bascompte J, Melián CJ. Simple trophic modules for complex food webs. Ecology 86(11):2868–73 (2005).
A.
B.
C.
D.
E.
Editorial response: Explain the scientific reasoning and any limitation of the original choices.

Question 4

1. Through their nose
2. Through their mouth
3. Through their gills
4. Through their skin
5. Through body openings

Question 5

Question 6

While you were preparing bread for breakfast, you observed microorganisms growing on it, making it no longer safe for consumption. Which type of microorganisms were growing on the bread?

Image source: https://commons.wikimedia.org/

1. Algae
2. Bacteria
3. Viruses
4. Fungi
5. Protozoan

Question 7

What property does the following device measure?

Image credit: Michael Allen Smith, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=54002461

1. hotness or coldness of matter
2. space occupied by matter
3. amount of matter
4. color
5. texture

Question 8

1. cork < liquid < stone
2. cork < stone < liquid
3. stone < liquid < cork
4. liquid < stone < cork
5. liquid < cork < stone

Question 9

1. 0.7 g/mL
2. 7 mL/g
3. 5.0 g/mL
4. 1.4 g/mL
5. 1.4 mL/g

Question 10

1. 83 g
2. 56 g
3. 160 g
4. 21 g
5. cannot be determined from the given information

Question 11

1. flame
2. flame and fuel
3. flame, fuel, and oxygen
4. oxygen, fuel, source of heat
5. flame, oxygen, source of heat, fuel

Question 12

Bulalo soup is a popular Filipino beef stew made from beef broth, vegetables, and corn. Bulalo is best characterized as a ______.

Image credit: Marife.altabano, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=127617548

1. liquid
2. solid
3. solution
4. suspension
5. mixture

Question 13

A ship leaves Manila bay at 6:00. Shown below is the distance travelled by the ship over time. When is the ship travelling the FASTEST?

1. From 7:00 to 8:00
2. From 8:00 to 9:00
3. From 9:00 to 10:00
4. From 10:00 to 11:00
5. From 11:00 to 12:00

Question 14

Refer to the previous question. When is the ship’s speed 0 ?

1. From 7:00 to 8:00
2. From 8:00 to 9:00
3. From 9:00 to 10:00
4. From 10:00 to 11:00
5. From 11:00 to 12:00

Question 15

The Banaue Rice Terraces is a famous Philippine landmark. Built over a thousand years ago, the terraces allowed to grow rice even on mountains. On which part of the rice terraces would you have the highest kinetic energy?

Image credit: Edwin Juen Jr., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=72812167
A. A
B. B
C. C
Editorial response: Explain the scientific reasoning and any limitation of the original choices.

Question 16

A battery powered alarm clock converts this stored energy into what form of energy when the alarm comes off?

Image credit: Videoplasty.com, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=67044528

1. sound energy
2. mechanical energy
3. light
4. potential energy
5. heat

Question 17

Ovens can cook food even if the food is NOT in direct contact with the food being cooked. This is because the air inside the oven transfers heat to the food. This illustrates what kind of heat transfer?

Image credit: Vyacheslav Argenberg, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=104997108

1. conduction
2. convection
3. radiation
4. induction
5. none of the above

Question 18

1. chemical energy
2. potential energy
3. heat
4. light
5. mechanical energy

Question 19

1. Spring
2. Summer
3. Fall
4. Winter
5. None of the above

Question 20