- The mantle of the earth is mainly made of silicate
- The crust of the earth is made of basalt or granite
- So, the mantle of the earth is mainly made of silicate and the crust of the earth is made of basalt or ganite

- Basalt is a kind of material
- Granite is a kind of material
- Silicate is a kind of material
- Therefore, silicate, basalt, and granite are kinds of materials

- The mantle of the earth is mainly made of silicate and the crust of the earth is made of basalt or ganite
- Silicate, basalt, and granite are kinds of materials
- Different media are made of different materials
- Hence, the mantle and the crust are different media

- The mantle and the crust are different media
- Waves travel at different speed in different medium
- Therefore, waves will travel at different speed in the mantle and the crust

- Waves will travel at different speed in the mantle and the crust
- An earthquake wave is a kind of wave
- So, earthquake waves will travel at different speed in the mantle and the crust

Hence, earthquake waves will travel at different speed in the mantle and the crust
[Question]When an earthquake wave passes from the crust to the mantle, the wave
[Context]- Basalt is a kind of material 
- Granite is a kind of material 
- The mantle of the earth is mainly made of silicate 
- Silicate is a kind of material 
- Waves travel at different speed in different medium 
- Different media are made of different materials 
- An earthquake wave is a kind of wave 
- The crust of the earth is made of basalt or granite