Unit Test 2 Revision 3 5th April 2021

1. TRUE or FALSE? Felt papers are good materials for making umbrella because it repels water. Could this be true? Explain why.

• TRUE

  Because felt papers are waterproof materials. Hence, it repels water rather than absorbing it.

• FALSE

  Because felt papers are absorbent materials. Hence, it absorbs water rather than repelling it.

2. TRUE or FALSE? They say that toothpicks could carry a heavy load (like a brick) even if it’s weak and feeble. Could this be true? Explain why.

• TRUE

  Because when toothpicks are shaped into tetrahedrons it will make the structure very strong, stable and with base support that it can carry a heavy load even a brick.

• FALSE

  Because when toothpicks are shaped into cube it will make the structure very strong, stable and with base support that it can carry a heavy load even a brick.

3. TRUE or FALSE? People needs to use bamboo grass as the essential material for building the wall of a house for it to be strong and durable. Can this be true? Explain why.

• TRUE

  Because to build a strong and durable house we need to use bamboo and leaves for the wall of a house.

• FALSE

  Because to build a strong and durable house we need to use bricks or concrete blocks for the wall of a house.

4. TRUE or FALSE? Tennis players need to wear clothes that are made of nylon or cotton materials to be able to move freely during the game. Could this be true? Explain why.

• TRUE

  Because nylon or cotton are soft and elastic materials that will move with their body as they play or move around.

• FALSE

  Because nylon or cotton are rough and rigid materials that will be stiff with their body as they play or move around.

5. TRUE or FALSE? Cruise ships (like Titanic) can float on water even if it is so big and so heavy and humongous. Could this be true? Explain why.

• FALSE

  Because ships have shallow hull with low edges or decks that take in water or displaces water as much as it does, making it heavier for its size. Plus cruise ships nowadays have gasoline pumps that fills with air for it to float and not tip during windy weather.

• TRUE

  Because ships have hollow hull with high edges or decks that pushes aside water or displaces water as much as it does, making it lighter for its size. Plus cruise ships nowadays have ballasts that fills with air for it to float and not tip during windy weather.

6. What is the source of material for a glass?

• a. stone

• b. plastic

• c. oil

• d. sand

7. Glass repels water or liquid. What is the property of glass?

• a. absorbent

• b. flexible

• c. waterproof

• d. elastic

8. Among the set of materials in this table, which one is slightly elastic?

• rubber tyres

• glass bottles

• rubber bands

• soccer ball

9. Which material is a sponge made from?

• a. foam

• b. plastic

• c. rubber

• d. silicon

10. Rain coats are worn during rainy days. What is the property of rain coats?

• a. absorbent

• b. rigid

• c waterproof

• d. brittle