Olibits / Science / Light, Heat & Matter Enrichment
Primary 4 Science: Light, Heat & Matter Enrichment Practice
Real Primary 4 Science questions on Light, Heat & Matter Enrichment, pulled directly from the Olibits question bank — the same questions a child would actually see, not separately written for this page.
Curriculum alignment
Science Teaching & Learning Syllabus, Primary Three to Six (MOE, 2023 syllabus)
Science is not a taught subject at P1/P2 under MOE's own syllabus — our P1/P2 Science content is offered as enrichment beyond the official syllabus, not as a claim of syllabus coverage at those grades.
Olibits is an independent learning platform and is not affiliated with or endorsed by the Ministry of Education. See our FAQ for the full breakdown.
Enrichment topic. This goes beyond what the MOE syllabus asks at this level. It is offered as extra practice, not as syllabus coverage.
Real Light, Heat & Matter Enrichment practice questions
A sealed container holds a small amount of liquid water and empty space above it. Over time, some water evaporates into the empty space, but eventually the liquid level stops decreasing even though the container is still sealed and at the same temperature. What is the best explanation?
The water at the bottom is too heavy to evaporate, so only the water in the top layer can ever change
The sealed lid stops heat from reaching the water, so evaporation stops completely
Water vapour builds up until as much condenses as evaporates, so the water level stops changing ✓
The water vapour freezes onto the lid, so no more liquid can evaporate
Water vapour builds up in the space above the water. Soon the vapour turns back into liquid as fast as the water evaporates, so the water level stays the same.
An advertisement claims: 'Our SuperFlask keeps drinks hot for 24 hours!' A pupil tests it: fills it with 90°C water, and after 6 hours it reads 81°C. He assumes it must be able to reach 24 hours based on this trend continuing at the same rate. What is wrong with this reasoning?
Heat loss speeds up as the water gets cooler, so the flask will cool faster later on and not stay hot
A good flask should show no drop in temperature at all in 6 hours, so the reading of 81°C must be wrong
Heat loss usually slows as the water nears room temperature, so the rate cannot be assumed constant ✓
Nothing is wrong, because the 6-hour trend proves that the flask will stay hot for 24 hours
The water lost 9°C in the first 6 hours. As the water cools, the difference between its temperature and the room's gets smaller, so heat flows out more slowly. The rate will not stay the same, so a real reading at 24 hours is needed.
A group of pupils builds a pinhole camera using a shoebox with a tiny pinhole on one side and tracing paper as a screen on the other. When they make the pinhole bigger with a pencil, what most likely happens to the image on the screen?
The image becomes brighter but blurrier ✓
The image becomes dimmer and blurrier
The image becomes brighter and much sharper
The image becomes dimmer and sharper
A very small pinhole lets only a narrow, well-defined ray of light from each point of the object through, which keeps the image sharp but dim. Making the hole bigger lets in more light, so the image looks brighter, but each point on the object now sends a wider spread of rays through the hole, which overlap on the screen and blur the image.
A submarine periscope has a mirror at the top AND a mirror at the bottom of its tube. If a pupil built a version with only the TOP mirror (angled to send light down the tube) but no bottom mirror, what would happen when someone tried to look into the bottom of the tube?
They would see a normal image, because one mirror does the same job as two
They would see a brighter image, because the tube fills with more light
They would see no useful image, because the light goes straight past their eye ✓
The image would be upside down, because only one mirror is used
The top mirror turns the light downwards, and the light keeps travelling straight down. To reach the eye, the light must be turned sideways. This is the job of the bottom mirror. Without it, the light goes past the opening and no useful image is seen.