Science For 7-8 Year Olds

1. Which of these does not conduct electricity?

Iron

Copper

Wood

Silver

Wood does not conduct electricity because it is an insulator. Unlike metals such as iron, copper, and silver, wood does not have free electrons that can move and carry electric charge. The structure of wood is made up of tightly bound atoms and molecules, which restricts the flow of electric current. Therefore, wood is not a conductor of electricity.

Explanation

Wood does not conduct electricity because it is an insulator. Unlike metals such as iron, copper, and silver, wood does not have free electrons that can move and carry electric charge. The structure of wood is made up of tightly bound atoms and molecules, which restricts the flow of electric current. Therefore, wood is not a conductor of electricity.

2. Which is harder than the other?

Gold is harder than iron

Iron is harder than gold

In terms of hardness, iron is generally considered harder than gold. Hardness is a measure of a material's resistance to scratching or indentation. Iron has a higher hardness rating on the Mohs scale compared to gold. Iron's hardness is attributed to its crystal structure and the presence of carbon impurities, which make it more resistant to deformation. Gold, on the other hand, is a relatively soft metal and can be easily scratched or dented. Therefore, iron is harder than gold.

Explanation

In terms of hardness, iron is generally considered harder than gold. Hardness is a measure of a material's resistance to scratching or indentation. Iron has a higher hardness rating on the Mohs scale compared to gold. Iron's hardness is attributed to its crystal structure and the presence of carbon impurities, which make it more resistant to deformation. Gold, on the other hand, is a relatively soft metal and can be easily scratched or dented. Therefore, iron is harder than gold.

3. What is 0 degrees Centigrade in Fahrenheit?

100 degrees Fahrenheit

32 degrees Fahrenheit

1 degree Fahrenheit

Minus 10 degrees Fahrenheit

0 degrees Centigrade is equivalent to 32 degrees Fahrenheit. This is because the freezing point of water is 0 degrees Centigrade and 32 degrees Fahrenheit. The two temperature scales have different starting points and different intervals, but they intersect at this specific temperature.

Explanation

0 degrees Centigrade is equivalent to 32 degrees Fahrenheit. This is because the freezing point of water is 0 degrees Centigrade and 32 degrees Fahrenheit. The two temperature scales have different starting points and different intervals, but they intersect at this specific temperature.

4. Which is NOT a name of a cloud?

Nimbus

Cumulus

Cirrus

Columbus

The name "Columbus" does not correspond to any type of cloud. Nimbus, Cumulus, and Cirrus are all actual cloud names used to describe different types of clouds. However, "Columbus" does not fit into this category and is not recognized as a cloud name.

Explanation

The name "Columbus" does not correspond to any type of cloud. Nimbus, Cumulus, and Cirrus are all actual cloud names used to describe different types of clouds. However, "Columbus" does not fit into this category and is not recognized as a cloud name.

5. Two magnets that are held close repel each other if the poles facing each other are:

Positive and positive

Negative and negative

Either answer A or B are correct

Negative and positive

None of the above are correct

The explanation for the given answer is that two magnets held close to each other will repel each other if the poles facing each other are either positive and positive or negative and negative. This is because like poles repel each other, while opposite poles attract. Therefore, if the poles facing each other are the same (either positive or negative), the magnets will repel each other.

Explanation

The explanation for the given answer is that two magnets held close to each other will repel each other if the poles facing each other are either positive and positive or negative and negative. This is because like poles repel each other, while opposite poles attract. Therefore, if the poles facing each other are the same (either positive or negative), the magnets will repel each other.