Fibre to Fabric — Science STD 6 — Question

Give example of an object which is:

1. Opaque and luminous.
2. Translucent and luminous.

Activity.

1. Make a mixture of dry sand with sawdust or powdered dry leaves. Keep this mixture on a plate or a newspaper. Look at this mixture carefully.

Can the two different components be made out easily? Are the sizes of particles of the two; components similar? Would it be possible to separate the components by handpicking?

2. Now, take your mixture to an open ground and stand on a raised platform. Put the mixture in a plate or sheet of paper. Hold the plate or the sheet of paper containing the mixture, at your shoulder height. Tilt it slightly, so that the mixture slides out slowly.

What happens? Do both the components– sand and sawdust (or powdered leaves) fall at the same place? Is there a component that blows away? Did the wind manage to separate the two components?

The following is an answer given by Boojho to a question asked by his teacher- “Cotton, wool, silk and jute are classified as natural fibres whereas nylon and polyester are classified as synthetic fibres.”
Can you tell what question the teacher has asked?

A toy car has a bar magnet laid hidden inside its body along its length. Using another magnet how will you find out which pole of the magnet is facing the front of the car?

The photograph given as Fig. shows a section of a grille made up of straight and curved iron bars. How would you measure the length of the bars of this section, so that the payment could be made to the contractor?

Is air a good or a bad conductor of electricity?

How does a squid move in water?

A bar magnet has no markings to indicate its poles. How would you find out near which end its North pole is located without using another magnet?

Mixtures of red chilli powder in water, butter in water, petrol in water and honey in water were given to Radha, Sudha, Sofia and Raveena, respectively. Whose mixture is in solution form?

Tara and Vijay set up the experiment’ shown in the picture (Fig. below). What do you think they want to find out? How will they know if they are correct?

Experimental set-up