You must have seen an electrician using his screw driver. What kind of handle does it have? Why?

You may have seen in a circus a motorcyclist driving in vertical loops inside a ‘death-well’ (a hollow spherical chamber with holes, so the spectators can watch from outside). Explain clearly why the motorcyclist does not drop down when he is at the uppermost point, with no support from below: What is the minimum speed required at the uppermost position to perform a vertical loop if the radius of the chamber is 25 m?

You have seen that a number 450 is divisible by 10. It is also divisible by 2 and 5 which are factors of 10. Similarly, a number 135 is divisible by 9. It is also divisible by 3 which is a factor of 9. Can you say that if a number is divisible by any number m, then it will also be divisible by each of the factors of m?

Why does the earth have an atmosphere and the moon does not?

Why do you have to use paper or kerosene oil to start fire in wood or coal?

Using Theorem 6.2, prove that the line joining the mid-points of any two sides of a triangle is parallel to the third side. (Recall that you have done it in class IX).