Science Fest - Round 3

A cactus is a desert plant. It is covered with spines. The spines are modified leaves. Why are leaves in a cactus modified into spines?

• spines attract insects to the plant

• spines provide more shade for the plant

• spines make more food for the plant

• spines reduce water loss from the plant

Sania installs solar panels on the rooftop to produce electricity. During which part of the day does a solar panel produce the most electricity?

• Sunrise

• Midday

• Sunset

• Midnight

Substances that allow electricity to flow through them are called conductors. What conclusion can be made from the above experiment?

• Only copper and silver are conductors.

• Only rubber and plastic are conductors.

• None of these substances are conductors.

• All these substances are conductors.

Amina put 100 mL of water in a glass. She added one small spoon of sugar and stirred with the spoon. After the sugar dissolved she measured the volume. It was still 100 mL. What is the best explanation for this?

• There are small spaces in the water where dissolved sugar can fit in.

• Some of the water evaporates when another substance is added.

• The glass expands slightly when more sugar is added.

• Water begins to shrink when it is mixed with other substances.

Use the table below to answer questions 5 and 6.

Which is the warmest planet?

• Mercury

• Venus

• Earth

• Mars

Which two planets are most similar in size?

• Jupiter and Saturn

• Earth and Venus

• Uranus and Neptune

• Mercury and Mars

Rupak wants to find out if salt dissolves more quickly in hot or cold water. He fills two beakers, one with hot water and the other with cold water. What should Rupak do for a fair investigation?

• add equal amounts of salt to equal amounts of water

• add more salt to the hot water

• stir the cold water more than the hot water

• add salt to a third beaker containing tap water

Shenaz is not sure if the tap water is safe to drink. What can Shenaz do to make the water safe to drink?

• boil the water

• freeze the water

• keep the water at a constant temperature

• store the water for few days and then use it