Bimetallic strip,uneven expansion of glass

If boiling water is poured into thick glass, it often cracks. This is because... 

• of the unequal expansion and contraction of the inner and out glass layer.
• the outer glass layer expands more than the inner glass layer when in contact with water.
• the glass is very fragile. 
• the difference in temperature between the inside and outside of glass in very big.

Bimetallic strips are commonly found in all of the following except...

• electric iron.
• rice cooker.
• refrigerator.
• clinic thermometer.

A bimetallic strip is made up of _____________________ welded together.

• two metals of the same kind 
• two different metals that expand and contract unequally
• two different metals that expand and contract equally

The picture shows a bimetallic strip in a fire alarm. When there is a fire outbreak, the bimetallic strip will get hot, ....

• bend downwards, complete the circuit and the alarm rings.
• bend upwards, open the circuit and the alarm will not ring.
• becomes longer, open the circuit and the alarm will not ring.

Which metal, A or B, expands the most upon heating? And what metal is it?

• A; Iron
• A; Brass
• B; Iron
• B; Brass

What is a thermostat?

• It keeps temperature high all the time.
• It keeps temperature low all the time.
• It keeps the temperature constant all the time.

A ____ is used in a thermostat to maintain constant temperature and it ______ when heated, making or breaking the circuit.

• movement joint, rotates

• bimetallic strip, rotates

• movement joint, bends

• bimetallic strip, bends

How are overhead electrical wire lines installed?

• They are installed tightly

• They are installed loosely

• They are installed by magnetic waves

• They are installed wirelessly

Many objects, such as train tracks and road joints, are specifically designed to allow extra space for ...

• thermal energy
• specific heat
• thermal expansion
• conductors

Tags

NGSS.MS-ETS1-1

NGSS.MS-PS3-3