Assignments - 7th Grade- Science (Archived)
minerals 2018
Due Date: 1/12/2018
Subject: 7th Grade- Science

Mineral Quiz 1 – 2018


1.     Which type of igneous rock usually has relatively larger crystals (grains)?

a.     extrusive

b.     intrusive

c.      obtrusive

d.     paratrusive


2.     Explain why.


3.     Which type of igneous rock usually has relatively smaller crystals (grains)?

a.     extrusive

b.     intrusive

c.      obtrusive

d.     paratrusive


4.     Explain why.


5.     What does Mohs scale measure with respect to minerals?

a.     density

b.     hardness

c.      luster

d.     texture


6.     The color of the residual powder resulting from the scrape (rub) of a mineral on an unglazed tile is called a mineral’s _______________.

a.     cleavage

b.     fracture

c.      luminescence

d.     streak


7.     Talc is (soft/hard) with a Mohs scale number of____________.


8.     Diamonds are (soft/hard) with a Mohs scale number of __________.


9.     Intrusive igneous rock is formed, cooled and solidified, from (lava/magma)

(above ground/under ground).


10. Extrusive igneous rock is formed, cooled and solidified, from (lava/magma)

(above ground/under ground).


11. The main factors in the formation of metamorphic rock are ____________.

a.     melting and cooling

b.     deposition and compaction

c.      heat and pressure

d.     weathering and erosion

12. The primary raw materials from which sedimentary rocks are formed are ____________

a.     lava from volcanic eruptions

b.     weathered remains of other rocks

c.      other rocks subjected to extreme heat and pressure

d.     magma from the mantle


13. Sand on a beach is covered by other layers of sand over time. The extra layers compact the first layer, packing it tighter and tighter. Over time, the bottom layers of sand form into sandstone with colored bands showing the different layers. What kind of rock can this sandstone be classified as?

a.     igneous rock

b.     volcanic rock

c.      sedimentary rock

d.     metamorphic rock


14. Granite is a type of igneous rock. What determines the size of the crystals that form in granite?

a.     how many impurities are in the granite

b.     how large the granite deposit is

c.      Iron Man

d.     how quickly the rock cooled


15. When rocks break down or decompose, they can form __________.

a.     lava

b.     magma

c.      soil

d.     bigger rocks


16. __________________ is the name for the process of recycling materials that make up Earth’s crust (and mantle).

a.     The water cycle

b.     The carbon cycle

c.      The rock cycle

d.     The nitrogen cycle


17. Metamorphic rocks are made from _____________.

a.     sedimentary rocks, igneous rocks, other metamorphic rocks

b.     only other metamorphic rocks

c.      only sedimentary rocks and other metamorphic rocks

d.     only sedimentary and igneous rocks

meiosis video
Due Date: 11/13/2017
Subject: 7th Grade- Science




Due Date: 11/9/2017
Subject: 7th Grade- Science




Photosynthesis in leaves that are not green
Due Date: 9/19/2017
Subject: 7th Grade- Science

Photosynthesis in leaves that aren’t green – 2017 - Michael Ellis

How does photosynthesis occur in plants that are not obviously green, such as ornamental plum trees with deep purple-colored leaves?

Photosynthesis (which literally means “light put together”) is that very elegant chemical process that jump-started life as we know it some 4 billion years ago. So to answer your question, we’ll need a short chemistry lesson. Basically six molecules of water (H2O) plus six molecules of carbon dioxide (CO2) in the presence of light energy produce one molecule of glucose sugar (C6H12O6) and emit six molecules of oxygen (O2) as a by-product. That sugar molecule drives the living world. Animals eat plants, then breathe in oxygen, which is used to metabolize the sugar, releasing the solar energy stored in glucose and giving off carbon dioxide as a by-product. That’s life, in a nutshell.

All photosynthesizing plants have a pigment molecule called chlorophyll. This molecule absorbs most of the energy from the violet-blue and reddish-orange part of the light spectrum. It does not absorb green, so that’s reflected back to our eyes and we see the leaf as green. There are also accessory pigments, called carotenoids, that capture energy not absorbed by chlorophyll. There are at least 600 known carotenoids, divided into yellow xanthophylls and red and orange carotenes. They absorb blue light and appear yellow, red, or orange to our eyes. Anthocyanin is another important pigment that’s not directly involved in photosynthesis, but it gives red stems, leaves, flowers, or even fruits their color.

Many plants are selected as ornamentals because of their red leaves— purple smoke bush and Japanese plums and some Japanese maples, to name just a few. Obviously they manage to survive quite well without green leaves. At low light levels, green leaves are most efficient at photosynthesis. On a sunny day, however, there is essentially no difference between red and green leaves’ ability to trap the sun’s energy. I have noticed the presence of red in the new leaves of many Bay Area plants as well as in numerous tropical species. The red anthocyanins apparently prevent damage to leaves from intense light energy by absorbing ultraviolet light. There is also evidence that unpalatable compounds are often produced along with anthocyanins, which may be the plant’s way of advertising its toxicity to potential herbivores. So red-leaved plants get a little protection from ultraviolet light and send a warning to leaf-eating pests, but they lose a bit of photosynthetic efficiency in dimmer light.